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ffmpeg-codecs(1)                                              ffmpeg-codecs(1)




NAME

       ffmpeg-codecs - FFmpeg codecs


DESCRIPTION

       This document describes the codecs (decoders and encoders) provided by
       the libavcodec library.


CODEC OPTIONS

       libavcodec provides some generic global options, which can be set on
       all the encoders and decoders. In addition each codec may support so-
       called private options, which are specific for a given codec.

       Sometimes, a global option may only affect a specific kind of codec,
       and may be nonsensical or ignored by another, so you need to be aware
       of the meaning of the specified options. Also some options are meant
       only for decoding or encoding.

       Options may be set by specifying -option value in the FFmpeg tools, or
       by setting the value explicitly in the "AVCodecContext" options or
       using the libavutil/opt.h API for programmatic use.

       The list of supported options follow:

       b integer (encoding,audio,video)
           Set bitrate in bits/s. Default value is 200K.

       ab integer (encoding,audio)
           Set audio bitrate (in bits/s). Default value is 128K.

       bt integer (encoding,video)
           Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
           tolerance specifies how far ratecontrol is willing to deviate from
           the target average bitrate value. This is not related to min/max
           bitrate. Lowering tolerance too much has an adverse effect on
           quality.

       flags flags (decoding/encoding,audio,video,subtitles)
           Set generic flags.

           Possible values:

           mv4 Use four motion vector by macroblock (mpeg4).

           qpel
               Use 1/4 pel motion compensation.

           loop
               Use loop filter.

           qscale
               Use fixed qscale.

           pass1
               Use internal 2pass ratecontrol in first pass mode.

           pass2
               Use internal 2pass ratecontrol in second pass mode.

           gray
               Only decode/encode grayscale.

           psnr
               Set error[?] variables during encoding.

           truncated
               Input bitstream might be randomly truncated.

           drop_changed
               Don't output frames whose parameters differ from first decoded
               frame in stream.  Error AVERROR_INPUT_CHANGED is returned when
               a frame is dropped.

           ildct
               Use interlaced DCT.

           low_delay
               Force low delay.

           global_header
               Place global headers in extradata instead of every keyframe.

           bitexact
               Only write platform-, build- and time-independent data. (except
               (I)DCT).  This ensures that file and data checksums are
               reproducible and match between platforms. Its primary use is
               for regression testing.

           aic Apply H263 advanced intra coding / mpeg4 ac prediction.

           ilme
               Apply interlaced motion estimation.

           cgop
               Use closed gop.

           output_corrupt
               Output even potentially corrupted frames.

       time_base rational number
           Set codec time base.

           It is the fundamental unit of time (in seconds) in terms of which
           frame timestamps are represented. For fixed-fps content, timebase
           should be "1 / frame_rate" and timestamp increments should be
           identically 1.

       g integer (encoding,video)
           Set the group of picture (GOP) size. Default value is 12.

       ar integer (decoding/encoding,audio)
           Set audio sampling rate (in Hz).

       ac integer (decoding/encoding,audio)
           Set number of audio channels.

       cutoff integer (encoding,audio)
           Set cutoff bandwidth. (Supported only by selected encoders, see
           their respective documentation sections.)

       frame_size integer (encoding,audio)
           Set audio frame size.

           Each submitted frame except the last must contain exactly
           frame_size samples per channel. May be 0 when the codec has
           CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is
           not restricted. It is set by some decoders to indicate constant
           frame size.

       frame_number integer
           Set the frame number.

       delay integer
       qcomp float (encoding,video)
           Set video quantizer scale compression (VBR). It is used as a
           constant in the ratecontrol equation. Recommended range for default
           rc_eq: 0.0-1.0.

       qblur float (encoding,video)
           Set video quantizer scale blur (VBR).

       qmin integer (encoding,video)
           Set min video quantizer scale (VBR). Must be included between -1
           and 69, default value is 2.

       qmax integer (encoding,video)
           Set max video quantizer scale (VBR). Must be included between -1
           and 1024, default value is 31.

       qdiff integer (encoding,video)
           Set max difference between the quantizer scale (VBR).

       bf integer (encoding,video)
           Set max number of B frames between non-B-frames.

           Must be an integer between -1 and 16. 0 means that B-frames are
           disabled. If a value of -1 is used, it will choose an automatic
           value depending on the encoder.

           Default value is 0.

       b_qfactor float (encoding,video)
           Set qp factor between P and B frames.

       b_strategy integer (encoding,video)
           Set strategy to choose between I/P/B-frames.

       ps integer (encoding,video)
           Set RTP payload size in bytes.

       mv_bits integer
       header_bits integer
       i_tex_bits integer
       p_tex_bits integer
       i_count integer
       p_count integer
       skip_count integer
       misc_bits integer
       frame_bits integer
       codec_tag integer
       bug flags (decoding,video)
           Workaround not auto detected encoder bugs.

           Possible values:

           autodetect
           xvid_ilace
               Xvid interlacing bug (autodetected if fourcc==XVIX)

           ump4
               (autodetected if fourcc==UMP4)

           no_padding
               padding bug (autodetected)

           amv
           qpel_chroma
           std_qpel
               old standard qpel (autodetected per fourcc/version)

           qpel_chroma2
           direct_blocksize
               direct-qpel-blocksize bug (autodetected per fourcc/version)

           edge
               edge padding bug (autodetected per fourcc/version)

           hpel_chroma
           dc_clip
           ms  Workaround various bugs in microsoft broken decoders.

           trunc
               trancated frames

       strict integer (decoding/encoding,audio,video)
           Specify how strictly to follow the standards.

           Possible values:

           very
               strictly conform to an older more strict version of the spec or
               reference software

           strict
               strictly conform to all the things in the spec no matter what
               consequences

           normal
           unofficial
               allow unofficial extensions

           experimental
               allow non standardized experimental things, experimental
               (unfinished/work in progress/not well tested) decoders and
               encoders.  Note: experimental decoders can pose a security
               risk, do not use this for decoding untrusted input.

       b_qoffset float (encoding,video)
           Set QP offset between P and B frames.

       err_detect flags (decoding,audio,video)
           Set error detection flags.

           Possible values:

           crccheck
               verify embedded CRCs

           bitstream
               detect bitstream specification deviations

           buffer
               detect improper bitstream length

           explode
               abort decoding on minor error detection

           ignore_err
               ignore decoding errors, and continue decoding.  This is useful
               if you want to analyze the content of a video and thus want
               everything to be decoded no matter what. This option will not
               result in a video that is pleasing to watch in case of errors.

           careful
               consider things that violate the spec and have not been seen in
               the wild as errors

           compliant
               consider all spec non compliancies as errors

           aggressive
               consider things that a sane encoder should not do as an error

       has_b_frames integer
       block_align integer
       mpeg_quant integer (encoding,video)
           Use MPEG quantizers instead of H.263.

       rc_override_count integer
       maxrate integer (encoding,audio,video)
           Set max bitrate tolerance (in bits/s). Requires bufsize to be set.

       minrate integer (encoding,audio,video)
           Set min bitrate tolerance (in bits/s). Most useful in setting up a
           CBR encode. It is of little use elsewise.

       bufsize integer (encoding,audio,video)
           Set ratecontrol buffer size (in bits).

       i_qfactor float (encoding,video)
           Set QP factor between P and I frames.

       i_qoffset float (encoding,video)
           Set QP offset between P and I frames.

       dct integer (encoding,video)
           Set DCT algorithm.

           Possible values:

           auto
               autoselect a good one (default)

           fastint
               fast integer

           int accurate integer

           mmx
           altivec
           faan
               floating point AAN DCT

       lumi_mask float (encoding,video)
           Compress bright areas stronger than medium ones.

       tcplx_mask float (encoding,video)
           Set temporal complexity masking.

       scplx_mask float (encoding,video)
           Set spatial complexity masking.

       p_mask float (encoding,video)
           Set inter masking.

       dark_mask float (encoding,video)
           Compress dark areas stronger than medium ones.

       idct integer (decoding/encoding,video)
           Select IDCT implementation.

           Possible values:

           auto
           int
           simple
           simplemmx
           simpleauto
               Automatically pick a IDCT compatible with the simple one

           arm
           altivec
           sh4
           simplearm
           simplearmv5te
           simplearmv6
           simpleneon
           xvid
           faani
               floating point AAN IDCT

       slice_count integer
       ec flags (decoding,video)
           Set error concealment strategy.

           Possible values:

           guess_mvs
               iterative motion vector (MV) search (slow)

           deblock
               use strong deblock filter for damaged MBs

           favor_inter
               favor predicting from the previous frame instead of the current

       bits_per_coded_sample integer
       pred integer (encoding,video)
           Set prediction method.

           Possible values:

           left
           plane
           median
       aspect rational number (encoding,video)
           Set sample aspect ratio.

       sar rational number (encoding,video)
           Set sample aspect ratio. Alias to aspect.

       debug flags (decoding/encoding,audio,video,subtitles)
           Print specific debug info.

           Possible values:

           pict
               picture info

           rc  rate control

           bitstream
           mb_type
               macroblock (MB) type

           qp  per-block quantization parameter (QP)

           dct_coeff
           green_metadata
               display complexity metadata for the upcoming frame, GoP or for
               a given duration.

           skip
           startcode
           er  error recognition

           mmco
               memory management control operations (H.264)

           bugs
           buffers
               picture buffer allocations

           thread_ops
               threading operations

           nomc
               skip motion compensation

       cmp integer (encoding,video)
           Set full pel me compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       subcmp integer (encoding,video)
           Set sub pel me compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       mbcmp integer (encoding,video)
           Set macroblock compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       ildctcmp integer (encoding,video)
           Set interlaced dct compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       dia_size integer (encoding,video)
           Set diamond type & size for motion estimation.

           (1024, INT_MAX)
               full motion estimation(slowest)

           (768, 1024]
               umh motion estimation

           (512, 768]
               hex motion estimation

           (256, 512]
               l2s diamond motion estimation

           [2,256]
               var diamond motion estimation

           (-1,  2)
               small diamond motion estimation

           -1  funny diamond motion estimation

           (INT_MIN, -1)
               sab diamond motion estimation

       last_pred integer (encoding,video)
           Set amount of motion predictors from the previous frame.

       preme integer (encoding,video)
           Set pre motion estimation.

       precmp integer (encoding,video)
           Set pre motion estimation compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       pre_dia_size integer (encoding,video)
           Set diamond type & size for motion estimation pre-pass.

       subq integer (encoding,video)
           Set sub pel motion estimation quality.

       me_range integer (encoding,video)
           Set limit motion vectors range (1023 for DivX player).

       global_quality integer (encoding,audio,video)
       coder integer (encoding,video)
           Possible values:

           vlc variable length coder / huffman coder

           ac  arithmetic coder

           raw raw (no encoding)

           rle run-length coder

       context integer (encoding,video)
           Set context model.

       slice_flags integer
       mbd integer (encoding,video)
           Set macroblock decision algorithm (high quality mode).

           Possible values:

           simple
               use mbcmp (default)

           bits
               use fewest bits

           rd  use best rate distortion

       sc_threshold integer (encoding,video)
           Set scene change threshold.

       nr integer (encoding,video)
           Set noise reduction.

       rc_init_occupancy integer (encoding,video)
           Set number of bits which should be loaded into the rc buffer before
           decoding starts.

       flags2 flags (decoding/encoding,audio,video,subtitles)
           Possible values:

           fast
               Allow non spec compliant speedup tricks.

           noout
               Skip bitstream encoding.

           ignorecrop
               Ignore cropping information from sps.

           local_header
               Place global headers at every keyframe instead of in extradata.

           chunks
               Frame data might be split into multiple chunks.

           showall
               Show all frames before the first keyframe.

           export_mvs
               Export motion vectors into frame side-data (see
               "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
               also doc/examples/export_mvs.c.

           skip_manual
               Do not skip samples and export skip information as frame side
               data.

           ass_ro_flush_noop
               Do not reset ASS ReadOrder field on flush.

       export_side_data flags (decoding/encoding,audio,video,subtitles)
           Possible values:

           mvs Export motion vectors into frame side-data (see
               "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
               also doc/examples/export_mvs.c.

           prft
               Export encoder Producer Reference Time into packet side-data
               (see "AV_PKT_DATA_PRFT") for codecs that support it.

           venc_params
               Export video encoding parameters through frame side data (see
               "AV_FRAME_DATA_VIDEO_ENC_PARAMS") for codecs that support it.
               At present, those are H.264 and VP9.

           film_grain
               Export film grain parameters through frame side data (see
               "AV_FRAME_DATA_FILM_GRAIN_PARAMS").  Supported at present by
               AV1 decoders.

       threads integer (decoding/encoding,video)
           Set the number of threads to be used, in case the selected codec
           implementation supports multi-threading.

           Possible values:

           auto, 0
               automatically select the number of threads to set

           Default value is auto.

       dc integer (encoding,video)
           Set intra_dc_precision.

       nssew integer (encoding,video)
           Set nsse weight.

       skip_top integer (decoding,video)
           Set number of macroblock rows at the top which are skipped.

       skip_bottom integer (decoding,video)
           Set number of macroblock rows at the bottom which are skipped.

       profile integer (encoding,audio,video)
           Set encoder codec profile. Default value is unknown. Encoder
           specific profiles are documented in the relevant encoder
           documentation.

       level integer (encoding,audio,video)
           Possible values:

           unknown
       lowres integer (decoding,audio,video)
           Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.

       skip_threshold integer (encoding,video)
           Set frame skip threshold.

       skip_factor integer (encoding,video)
           Set frame skip factor.

       skip_exp integer (encoding,video)
           Set frame skip exponent.  Negative values behave identical to the
           corresponding positive ones, except that the score is normalized.
           Positive values exist primarily for compatibility reasons and are
           not so useful.

       skipcmp integer (encoding,video)
           Set frame skip compare function.

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           w53 5/3 wavelet, only used in snow

           w97 9/7 wavelet, only used in snow

           dctmax
           chroma
       mblmin integer (encoding,video)
           Set min macroblock lagrange factor (VBR).

       mblmax integer (encoding,video)
           Set max macroblock lagrange factor (VBR).

       mepc integer (encoding,video)
           Set motion estimation bitrate penalty compensation (1.0 = 256).

       skip_loop_filter integer (decoding,video)
       skip_idct        integer (decoding,video)
       skip_frame       integer (decoding,video)
           Make decoder discard processing depending on the frame type
           selected by the option value.

           skip_loop_filter skips frame loop filtering, skip_idct skips frame
           IDCT/dequantization, skip_frame skips decoding.

           Possible values:

           none
               Discard no frame.

           default
               Discard useless frames like 0-sized frames.

           noref
               Discard all non-reference frames.

           bidir
               Discard all bidirectional frames.

           nokey
               Discard all frames excepts keyframes.

           nointra
               Discard all frames except I frames.

           all Discard all frames.

           Default value is default.

       bidir_refine integer (encoding,video)
           Refine the two motion vectors used in bidirectional macroblocks.

       brd_scale integer (encoding,video)
           Downscale frames for dynamic B-frame decision.

       keyint_min integer (encoding,video)
           Set minimum interval between IDR-frames.

       refs integer (encoding,video)
           Set reference frames to consider for motion compensation.

       chromaoffset integer (encoding,video)
           Set chroma qp offset from luma.

       trellis integer (encoding,audio,video)
           Set rate-distortion optimal quantization.

       mv0_threshold integer (encoding,video)
       b_sensitivity integer (encoding,video)
           Adjust sensitivity of b_frame_strategy 1.

       compression_level integer (encoding,audio,video)
       min_prediction_order integer (encoding,audio)
       max_prediction_order integer (encoding,audio)
       timecode_frame_start integer (encoding,video)
           Set GOP timecode frame start number, in non drop frame format.

       bits_per_raw_sample integer
       channel_layout integer (decoding/encoding,audio)
           Possible values:

       request_channel_layout integer (decoding,audio)
           Possible values:

       rc_max_vbv_use float (encoding,video)
       rc_min_vbv_use float (encoding,video)
       ticks_per_frame integer (decoding/encoding,audio,video)
       color_primaries integer (decoding/encoding,video)
           Possible values:

           bt709
               BT.709

           bt470m
               BT.470 M

           bt470bg
               BT.470 BG

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           film
               Film

           bt2020
               BT.2020

           smpte428
           smpte428_1
               SMPTE ST 428-1

           smpte431
               SMPTE 431-2

           smpte432
               SMPTE 432-1

           jedec-p22
               JEDEC P22

       color_trc integer (decoding/encoding,video)
           Possible values:

           bt709
               BT.709

           gamma22
               BT.470 M

           gamma28
               BT.470 BG

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           linear
               Linear

           log
           log100
               Log

           log_sqrt
           log316
               Log square root

           iec61966_2_4
           iec61966-2-4
               IEC 61966-2-4

           bt1361
           bt1361e
               BT.1361

           iec61966_2_1
           iec61966-2-1
               IEC 61966-2-1

           bt2020_10
           bt2020_10bit
               BT.2020 - 10 bit

           bt2020_12
           bt2020_12bit
               BT.2020 - 12 bit

           smpte2084
               SMPTE ST 2084

           smpte428
           smpte428_1
               SMPTE ST 428-1

           arib-std-b67
               ARIB STD-B67

       colorspace integer (decoding/encoding,video)
           Possible values:

           rgb RGB

           bt709
               BT.709

           fcc FCC

           bt470bg
               BT.470 BG

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           ycocg
               YCOCG

           bt2020nc
           bt2020_ncl
               BT.2020 NCL

           bt2020c
           bt2020_cl
               BT.2020 CL

           smpte2085
               SMPTE 2085

           chroma-derived-nc
               Chroma-derived NCL

           chroma-derived-c
               Chroma-derived CL

           ictcp
               ICtCp

       color_range integer (decoding/encoding,video)
           If used as input parameter, it serves as a hint to the decoder,
           which color_range the input has.  Possible values:

           tv
           mpeg
               MPEG (219*2^(n-8))

           pc
           jpeg
               JPEG (2^n-1)

       chroma_sample_location integer (decoding/encoding,video)
           Possible values:

           left
           center
           topleft
           top
           bottomleft
           bottom
       log_level_offset integer
           Set the log level offset.

       slices integer (encoding,video)
           Number of slices, used in parallelized encoding.

       thread_type flags (decoding/encoding,video)
           Select which multithreading methods to use.

           Use of frame will increase decoding delay by one frame per thread,
           so clients which cannot provide future frames should not use it.

           Possible values:

           slice
               Decode more than one part of a single frame at once.

               Multithreading using slices works only when the video was
               encoded with slices.

           frame
               Decode more than one frame at once.

           Default value is slice+frame.

       audio_service_type integer (encoding,audio)
           Set audio service type.

           Possible values:

           ma  Main Audio Service

           ef  Effects

           vi  Visually Impaired

           hi  Hearing Impaired

           di  Dialogue

           co  Commentary

           em  Emergency

           vo  Voice Over

           ka  Karaoke

       request_sample_fmt sample_fmt (decoding,audio)
           Set sample format audio decoders should prefer. Default value is
           "none".

       pkt_timebase rational number
       sub_charenc encoding (decoding,subtitles)
           Set the input subtitles character encoding.

       field_order  field_order (video)
           Set/override the field order of the video.  Possible values:

           progressive
               Progressive video

           tt  Interlaced video, top field coded and displayed first

           bb  Interlaced video, bottom field coded and displayed first

           tb  Interlaced video, top coded first, bottom displayed first

           bt  Interlaced video, bottom coded first, top displayed first

       skip_alpha bool (decoding,video)
           Set to 1 to disable processing alpha (transparency). This works
           like the gray flag in the flags option which skips chroma
           information instead of alpha. Default is 0.

       codec_whitelist list (input)
           "," separated list of allowed decoders. By default all are allowed.

       dump_separator string (input)
           Separator used to separate the fields printed on the command line
           about the Stream parameters.  For example, to separate the fields
           with newlines and indentation:

                   ffprobe -dump_separator "
                                             "  -i ~/videos/matrixbench_mpeg2.mpg

       max_pixels integer (decoding/encoding,video)
           Maximum number of pixels per image. This value can be used to avoid
           out of memory failures due to large images.

       apply_cropping bool (decoding,video)
           Enable cropping if cropping parameters are multiples of the
           required alignment for the left and top parameters. If the
           alignment is not met the cropping will be partially applied to
           maintain alignment.  Default is 1 (enabled).  Note: The required
           alignment depends on if "AV_CODEC_FLAG_UNALIGNED" is set and the
           CPU. "AV_CODEC_FLAG_UNALIGNED" cannot be changed from the command
           line. Also hardware decoders will not apply left/top Cropping.


DECODERS

       Decoders are configured elements in FFmpeg which allow the decoding of
       multimedia streams.

       When you configure your FFmpeg build, all the supported native decoders
       are enabled by default. Decoders requiring an external library must be
       enabled manually via the corresponding "--enable-lib" option. You can
       list all available decoders using the configure option
       "--list-decoders".

       You can disable all the decoders with the configure option
       "--disable-decoders" and selectively enable / disable single decoders
       with the options "--enable-decoder=DECODER" /
       "--disable-decoder=DECODER".

       The option "-decoders" of the ff* tools will display the list of
       enabled decoders.


VIDEO DECODERS

       A description of some of the currently available video decoders
       follows.

   av1
       AOMedia Video 1 (AV1) decoder.

       Options

       operating_point
           Select an operating point of a scalable AV1 bitstream (0 - 31).
           Default is 0.

   rawvideo
       Raw video decoder.

       This decoder decodes rawvideo streams.

       Options

       top top_field_first
           Specify the assumed field type of the input video.

           -1  the video is assumed to be progressive (default)

           0   bottom-field-first is assumed

           1   top-field-first is assumed

   libdav1d
       dav1d AV1 decoder.

       libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.
       Requires the presence of the libdav1d headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libdav1d".

       Options

       The following options are supported by the libdav1d wrapper.

       framethreads
           Set amount of frame threads to use during decoding. The default
           value is 0 (autodetect).

       tilethreads
           Set amount of tile threads to use during decoding. The default
           value is 0 (autodetect).

       filmgrain
           Apply film grain to the decoded video if present in the bitstream.
           Defaults to the internal default of the library.

       oppoint
           Select an operating point of a scalable AV1 bitstream (0 - 31).
           Defaults to the internal default of the library.

       alllayers
           Output all spatial layers of a scalable AV1 bitstream. The default
           value is false.

   libdavs2
       AVS2-P2/IEEE1857.4 video decoder wrapper.

       This decoder allows libavcodec to decode AVS2 streams with davs2
       library.

   libuavs3d
       AVS3-P2/IEEE1857.10 video decoder.

       libuavs3d allows libavcodec to decode AVS3 streams.  Requires the
       presence of the libuavs3d headers and library during configuration.
       You need to explicitly configure the build with "--enable-libuavs3d".

       Options

       The following option is supported by the libuavs3d wrapper.

       frame_threads
           Set amount of frame threads to use during decoding. The default
           value is 0 (autodetect).


AUDIO DECODERS

       A description of some of the currently available audio decoders
       follows.

   ac3
       AC-3 audio decoder.

       This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as
       well as the undocumented RealAudio 3 (a.k.a. dnet).

       AC-3 Decoder Options

       -drc_scale value
           Dynamic Range Scale Factor. The factor to apply to dynamic range
           values from the AC-3 stream. This factor is applied exponentially.
           The default value is 1.  There are 3 notable scale factor ranges:

           drc_scale == 0
               DRC disabled. Produces full range audio.

           0 < drc_scale <= 1
               DRC enabled.  Applies a fraction of the stream DRC value.
               Audio reproduction is between full range and full compression.

           drc_scale > 1
               DRC enabled. Applies drc_scale asymmetrically.  Loud sounds are
               fully compressed.  Soft sounds are enhanced.

   flac
       FLAC audio decoder.

       This decoder aims to implement the complete FLAC specification from
       Xiph.

       FLAC Decoder options

       -use_buggy_lpc
           The lavc FLAC encoder used to produce buggy streams with high lpc
           values (like the default value). This option makes it possible to
           decode such streams correctly by using lavc's old buggy lpc logic
           for decoding.

   ffwavesynth
       Internal wave synthesizer.

       This decoder generates wave patterns according to predefined sequences.
       Its use is purely internal and the format of the data it accepts is not
       publicly documented.

   libcelt
       libcelt decoder wrapper.

       libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio
       codec.  Requires the presence of the libcelt headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libcelt".

   libgsm
       libgsm decoder wrapper.

       libgsm allows libavcodec to decode the GSM full rate audio codec.
       Requires the presence of the libgsm headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libgsm".

       This decoder supports both the ordinary GSM and the Microsoft variant.

   libilbc
       libilbc decoder wrapper.

       libilbc allows libavcodec to decode the Internet Low Bitrate Codec
       (iLBC) audio codec. Requires the presence of the libilbc headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libilbc".

       Options

       The following option is supported by the libilbc wrapper.

       enhance
           Enable the enhancement of the decoded audio when set to 1. The
           default value is 0 (disabled).

   libopencore-amrnb
       libopencore-amrnb decoder wrapper.

       libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
       Narrowband audio codec. Using it requires the presence of the
       libopencore-amrnb headers and library during configuration. You need to
       explicitly configure the build with "--enable-libopencore-amrnb".

       An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
       without this library.

   libopencore-amrwb
       libopencore-amrwb decoder wrapper.

       libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
       Wideband audio codec. Using it requires the presence of the
       libopencore-amrwb headers and library during configuration. You need to
       explicitly configure the build with "--enable-libopencore-amrwb".

       An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
       without this library.

   libopus
       libopus decoder wrapper.

       libopus allows libavcodec to decode the Opus Interactive Audio Codec.
       Requires the presence of the libopus headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libopus".

       An FFmpeg native decoder for Opus exists, so users can decode Opus
       without this library.


SUBTITLES DECODERS

   libaribb24
       ARIB STD-B24 caption decoder.

       Implements profiles A and C of the ARIB STD-B24 standard.

       libaribb24 Decoder Options

       -aribb24-base-path path
           Sets the base path for the libaribb24 library. This is utilized for
           reading of configuration files (for custom unicode conversions),
           and for dumping of non-text symbols as images under that location.

           Unset by default.

       -aribb24-skip-ruby-text boolean
           Tells the decoder wrapper to skip text blocks that contain half-
           height ruby text.

           Enabled by default.

   dvbsub
       Options

       compute_clut
           -1  Compute clut if no matching CLUT is in the stream.

           0   Never compute CLUT

           1   Always compute CLUT and override the one provided in the
               stream.

       dvb_substream
           Selects the dvb substream, or all substreams if -1 which is
           default.

   dvdsub
       This codec decodes the bitmap subtitles used in DVDs; the same
       subtitles can also be found in VobSub file pairs and in some Matroska
       files.

       Options

       palette
           Specify the global palette used by the bitmaps. When stored in
           VobSub, the palette is normally specified in the index file; in
           Matroska, the palette is stored in the codec extra-data in the same
           format as in VobSub. In DVDs, the palette is stored in the IFO
           file, and therefore not available when reading from dumped VOB
           files.

           The format for this option is a string containing 16 24-bits
           hexadecimal numbers (without 0x prefix) separated by commas, for
           example "0d00ee, ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b,
           0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c,
           7c127b".

       ifo_palette
           Specify the IFO file from which the global palette is obtained.
           (experimental)

       forced_subs_only
           Only decode subtitle entries marked as forced. Some titles have
           forced and non-forced subtitles in the same track. Setting this
           flag to 1 will only keep the forced subtitles. Default value is 0.

   libzvbi-teletext
       Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
       subtitles. Requires the presence of the libzvbi headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libzvbi".

       Options

       txt_page
           List of teletext page numbers to decode. Pages that do not match
           the specified list are dropped. You may use the special "*" string
           to match all pages, or "subtitle" to match all subtitle pages.
           Default value is *.

       txt_default_region
           Set default character set used for decoding, a value between 0 and
           87 (see ETS 300 706, Section 15, Table 32). Default value is -1,
           which does not override the libzvbi default. This option is needed
           for some legacy level 1.0 transmissions which cannot signal the
           proper charset.

       txt_chop_top
           Discards the top teletext line. Default value is 1.

       txt_format
           Specifies the format of the decoded subtitles.

           bitmap
               The default format, you should use this for teletext pages,
               because certain graphics and colors cannot be expressed in
               simple text or even ASS.

           text
               Simple text based output without formatting.

           ass Formatted ASS output, subtitle pages and teletext pages are
               returned in different styles, subtitle pages are stripped down
               to text, but an effort is made to keep the text alignment and
               the formatting.

       txt_left
           X offset of generated bitmaps, default is 0.

       txt_top
           Y offset of generated bitmaps, default is 0.

       txt_chop_spaces
           Chops leading and trailing spaces and removes empty lines from the
           generated text. This option is useful for teletext based subtitles
           where empty spaces may be present at the start or at the end of the
           lines or empty lines may be present between the subtitle lines
           because of double-sized teletext characters.  Default value is 1.

       txt_duration
           Sets the display duration of the decoded teletext pages or
           subtitles in milliseconds. Default value is -1 which means infinity
           or until the next subtitle event comes.

       txt_transparent
           Force transparent background of the generated teletext bitmaps.
           Default value is 0 which means an opaque background.

       txt_opacity
           Sets the opacity (0-255) of the teletext background. If
           txt_transparent is not set, it only affects characters between a
           start box and an end box, typically subtitles. Default value is 0
           if txt_transparent is set, 255 otherwise.


ENCODERS

       Encoders are configured elements in FFmpeg which allow the encoding of
       multimedia streams.

       When you configure your FFmpeg build, all the supported native encoders
       are enabled by default. Encoders requiring an external library must be
       enabled manually via the corresponding "--enable-lib" option. You can
       list all available encoders using the configure option
       "--list-encoders".

       You can disable all the encoders with the configure option
       "--disable-encoders" and selectively enable / disable single encoders
       with the options "--enable-encoder=ENCODER" /
       "--disable-encoder=ENCODER".

       The option "-encoders" of the ff* tools will display the list of
       enabled encoders.


AUDIO ENCODERS

       A description of some of the currently available audio encoders
       follows.

   aac
       Advanced Audio Coding (AAC) encoder.

       This encoder is the default AAC encoder, natively implemented into
       FFmpeg.

       Options

       b   Set bit rate in bits/s. Setting this automatically activates
           constant bit rate (CBR) mode. If this option is unspecified it is
           set to 128kbps.

       q   Set quality for variable bit rate (VBR) mode. This option is valid
           only using the ffmpeg command-line tool. For library interface
           users, use global_quality.

       cutoff
           Set cutoff frequency. If unspecified will allow the encoder to
           dynamically adjust the cutoff to improve clarity on low bitrates.

       aac_coder
           Set AAC encoder coding method. Possible values:

           twoloop
               Two loop searching (TLS) method.

               This method first sets quantizers depending on band thresholds
               and then tries to find an optimal combination by adding or
               subtracting a specific value from all quantizers and adjusting
               some individual quantizer a little.  Will tune itself based on
               whether aac_is, aac_ms and aac_pns are enabled.

           anmr
               Average noise to mask ratio (ANMR) trellis-based solution.

               This is an experimental coder which currently produces a lower
               quality, is more unstable and is slower than the default
               twoloop coder but has potential.  Currently has no support for
               the aac_is or aac_pns options.  Not currently recommended.

           fast
               Constant quantizer method.

               Uses a cheaper version of twoloop algorithm that doesn't try to
               do as many clever adjustments. Worse with low bitrates (less
               than 64kbps), but is better and much faster at higher bitrates.
               This is the default choice for a coder

       aac_ms
           Sets mid/side coding mode. The default value of "auto" will
           automatically use M/S with bands which will benefit from such
           coding. Can be forced for all bands using the value "enable", which
           is mainly useful for debugging or disabled using "disable".

       aac_is
           Sets intensity stereo coding tool usage. By default, it's enabled
           and will automatically toggle IS for similar pairs of stereo bands
           if it's beneficial.  Can be disabled for debugging by setting the
           value to "disable".

       aac_pns
           Uses perceptual noise substitution to replace low entropy high
           frequency bands with imperceptible white noise during the decoding
           process. By default, it's enabled, but can be disabled for
           debugging purposes by using "disable".

       aac_tns
           Enables the use of a multitap FIR filter which spans through the
           high frequency bands to hide quantization noise during the encoding
           process and is reverted by the decoder. As well as decreasing
           unpleasant artifacts in the high range this also reduces the
           entropy in the high bands and allows for more bits to be used by
           the mid-low bands. By default it's enabled but can be disabled for
           debugging by setting the option to "disable".

       aac_ltp
           Enables the use of the long term prediction extension which
           increases coding efficiency in very low bandwidth situations such
           as encoding of voice or solo piano music by extending constant
           harmonic peaks in bands throughout frames. This option is implied
           by profile:a aac_low and is incompatible with aac_pred. Use in
           conjunction with -ar to decrease the samplerate.

       aac_pred
           Enables the use of a more traditional style of prediction where the
           spectral coefficients transmitted are replaced by the difference of
           the current coefficients minus the previous "predicted"
           coefficients. In theory and sometimes in practice this can improve
           quality for low to mid bitrate audio.  This option implies the
           aac_main profile and is incompatible with aac_ltp.

       profile
           Sets the encoding profile, possible values:

           aac_low
               The default, AAC "Low-complexity" profile. Is the most
               compatible and produces decent quality.

           mpeg2_aac_low
               Equivalent to "-profile:a aac_low -aac_pns 0". PNS was
               introduced with the MPEG4 specifications.

           aac_ltp
               Long term prediction profile, is enabled by and will enable the
               aac_ltp option. Introduced in MPEG4.

           aac_main
               Main-type prediction profile, is enabled by and will enable the
               aac_pred option. Introduced in MPEG2.

           If this option is unspecified it is set to aac_low.

   ac3 and ac3_fixed
       AC-3 audio encoders.

       These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as
       well as the undocumented RealAudio 3 (a.k.a. dnet).

       The ac3 encoder uses floating-point math, while the ac3_fixed encoder
       only uses fixed-point integer math. This does not mean that one is
       always faster, just that one or the other may be better suited to a
       particular system. The ac3_fixed encoder is not the default codec for
       any of the output formats, so it must be specified explicitly using the
       option "-acodec ac3_fixed" in order to use it.

       AC-3 Metadata

       The AC-3 metadata options are used to set parameters that describe the
       audio, but in most cases do not affect the audio encoding itself. Some
       of the options do directly affect or influence the decoding and
       playback of the resulting bitstream, while others are just for
       informational purposes. A few of the options will add bits to the
       output stream that could otherwise be used for audio data, and will
       thus affect the quality of the output. Those will be indicated
       accordingly with a note in the option list below.

       These parameters are described in detail in several publicly-available
       documents.

       *<<http://www.atsc.org/cms/standards/a_52-2010.pdf>>
       *<<http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf>>

       Metadata Control Options

       -per_frame_metadata boolean
           Allow Per-Frame Metadata. Specifies if the encoder should check for
           changing metadata for each frame.

           0   The metadata values set at initialization will be used for
               every frame in the stream. (default)

           1   Metadata values can be changed before encoding each frame.

       Downmix Levels

       -center_mixlev level
           Center Mix Level. The amount of gain the decoder should apply to
           the center channel when downmixing to stereo. This field will only
           be written to the bitstream if a center channel is present. The
           value is specified as a scale factor. There are 3 valid values:

           0.707
               Apply -3dB gain

           0.595
               Apply -4.5dB gain (default)

           0.500
               Apply -6dB gain

       -surround_mixlev level
           Surround Mix Level. The amount of gain the decoder should apply to
           the surround channel(s) when downmixing to stereo. This field will
           only be written to the bitstream if one or more surround channels
           are present. The value is specified as a scale factor.  There are 3
           valid values:

           0.707
               Apply -3dB gain

           0.500
               Apply -6dB gain (default)

           0.000
               Silence Surround Channel(s)

       Audio Production Information

       Audio Production Information is optional information describing the
       mixing environment.  Either none or both of the fields are written to
       the bitstream.

       -mixing_level number
           Mixing Level. Specifies peak sound pressure level (SPL) in the
           production environment when the mix was mastered. Valid values are
           80 to 111, or -1 for unknown or not indicated. The default value is
           -1, but that value cannot be used if the Audio Production
           Information is written to the bitstream. Therefore, if the
           "room_type" option is not the default value, the "mixing_level"
           option must not be -1.

       -room_type type
           Room Type. Describes the equalization used during the final mixing
           session at the studio or on the dubbing stage. A large room is a
           dubbing stage with the industry standard X-curve equalization; a
           small room has flat equalization.  This field will not be written
           to the bitstream if both the "mixing_level" option and the
           "room_type" option have the default values.

           0
           notindicated
               Not Indicated (default)

           1
           large
               Large Room

           2
           small
               Small Room

       Other Metadata Options

       -copyright boolean
           Copyright Indicator. Specifies whether a copyright exists for this
           audio.

           0
           off No Copyright Exists (default)

           1
           on  Copyright Exists

       -dialnorm value
           Dialogue Normalization. Indicates how far the average dialogue
           level of the program is below digital 100% full scale (0 dBFS).
           This parameter determines a level shift during audio reproduction
           that sets the average volume of the dialogue to a preset level. The
           goal is to match volume level between program sources. A value of
           -31dB will result in no volume level change, relative to the source
           volume, during audio reproduction. Valid values are whole numbers
           in the range -31 to -1, with -31 being the default.

       -dsur_mode mode
           Dolby Surround Mode. Specifies whether the stereo signal uses Dolby
           Surround (Pro Logic). This field will only be written to the
           bitstream if the audio stream is stereo. Using this option does NOT
           mean the encoder will actually apply Dolby Surround processing.

           0
           notindicated
               Not Indicated (default)

           1
           off Not Dolby Surround Encoded

           2
           on  Dolby Surround Encoded

       -original boolean
           Original Bit Stream Indicator. Specifies whether this audio is from
           the original source and not a copy.

           0
           off Not Original Source

           1
           on  Original Source (default)

       Extended Bitstream Information

       The extended bitstream options are part of the Alternate Bit Stream
       Syntax as specified in Annex D of the A/52:2010 standard. It is grouped
       into 2 parts.  If any one parameter in a group is specified, all values
       in that group will be written to the bitstream.  Default values are
       used for those that are written but have not been specified.  If the
       mixing levels are written, the decoder will use these values instead of
       the ones specified in the "center_mixlev" and "surround_mixlev" options
       if it supports the Alternate Bit Stream Syntax.

       Extended Bitstream Information - Part 1

       -dmix_mode mode
           Preferred Stereo Downmix Mode. Allows the user to select either
           Lt/Rt (Dolby Surround) or Lo/Ro (normal stereo) as the preferred
           stereo downmix mode.

           0
           notindicated
               Not Indicated (default)

           1
           ltrt
               Lt/Rt Downmix Preferred

           2
           loro
               Lo/Ro Downmix Preferred

       -ltrt_cmixlev level
           Lt/Rt Center Mix Level. The amount of gain the decoder should apply
           to the center channel when downmixing to stereo in Lt/Rt mode.

           1.414
               Apply +3dB gain

           1.189
               Apply +1.5dB gain

           1.000
               Apply 0dB gain

           0.841
               Apply -1.5dB gain

           0.707
               Apply -3.0dB gain

           0.595
               Apply -4.5dB gain (default)

           0.500
               Apply -6.0dB gain

           0.000
               Silence Center Channel

       -ltrt_surmixlev level
           Lt/Rt Surround Mix Level. The amount of gain the decoder should
           apply to the surround channel(s) when downmixing to stereo in Lt/Rt
           mode.

           0.841
               Apply -1.5dB gain

           0.707
               Apply -3.0dB gain

           0.595
               Apply -4.5dB gain

           0.500
               Apply -6.0dB gain (default)

           0.000
               Silence Surround Channel(s)

       -loro_cmixlev level
           Lo/Ro Center Mix Level. The amount of gain the decoder should apply
           to the center channel when downmixing to stereo in Lo/Ro mode.

           1.414
               Apply +3dB gain

           1.189
               Apply +1.5dB gain

           1.000
               Apply 0dB gain

           0.841
               Apply -1.5dB gain

           0.707
               Apply -3.0dB gain

           0.595
               Apply -4.5dB gain (default)

           0.500
               Apply -6.0dB gain

           0.000
               Silence Center Channel

       -loro_surmixlev level
           Lo/Ro Surround Mix Level. The amount of gain the decoder should
           apply to the surround channel(s) when downmixing to stereo in Lo/Ro
           mode.

           0.841
               Apply -1.5dB gain

           0.707
               Apply -3.0dB gain

           0.595
               Apply -4.5dB gain

           0.500
               Apply -6.0dB gain (default)

           0.000
               Silence Surround Channel(s)

       Extended Bitstream Information - Part 2

       -dsurex_mode mode
           Dolby Surround EX Mode. Indicates whether the stream uses Dolby
           Surround EX (7.1 matrixed to 5.1). Using this option does NOT mean
           the encoder will actually apply Dolby Surround EX processing.

           0
           notindicated
               Not Indicated (default)

           1
           on  Dolby Surround EX Off

           2
           off Dolby Surround EX On

       -dheadphone_mode mode
           Dolby Headphone Mode. Indicates whether the stream uses Dolby
           Headphone encoding (multi-channel matrixed to 2.0 for use with
           headphones). Using this option does NOT mean the encoder will
           actually apply Dolby Headphone processing.

           0
           notindicated
               Not Indicated (default)

           1
           on  Dolby Headphone Off

           2
           off Dolby Headphone On

       -ad_conv_type type
           A/D Converter Type. Indicates whether the audio has passed through
           HDCD A/D conversion.

           0
           standard
               Standard A/D Converter (default)

           1
           hdcd
               HDCD A/D Converter

       Other AC-3 Encoding Options

       -stereo_rematrixing boolean
           Stereo Rematrixing. Enables/Disables use of rematrixing for stereo
           input. This is an optional AC-3 feature that increases quality by
           selectively encoding the left/right channels as mid/side. This
           option is enabled by default, and it is highly recommended that it
           be left as enabled except for testing purposes.

       cutoff frequency
           Set lowpass cutoff frequency. If unspecified, the encoder selects a
           default determined by various other encoding parameters.

       Floating-Point-Only AC-3 Encoding Options

       These options are only valid for the floating-point encoder and do not
       exist for the fixed-point encoder due to the corresponding features not
       being implemented in fixed-point.

       -channel_coupling boolean
           Enables/Disables use of channel coupling, which is an optional AC-3
           feature that increases quality by combining high frequency
           information from multiple channels into a single channel. The per-
           channel high frequency information is sent with less accuracy in
           both the frequency and time domains. This allows more bits to be
           used for lower frequencies while preserving enough information to
           reconstruct the high frequencies. This option is enabled by default
           for the floating-point encoder and should generally be left as
           enabled except for testing purposes or to increase encoding speed.

           -1
           auto
               Selected by Encoder (default)

           0
           off Disable Channel Coupling

           1
           on  Enable Channel Coupling

       -cpl_start_band number
           Coupling Start Band. Sets the channel coupling start band, from 1
           to 15. If a value higher than the bandwidth is used, it will be
           reduced to 1 less than the coupling end band. If auto is used, the
           start band will be determined by the encoder based on the bit rate,
           sample rate, and channel layout. This option has no effect if
           channel coupling is disabled.

           -1
           auto
               Selected by Encoder (default)

   flac
       FLAC (Free Lossless Audio Codec) Encoder

       Options

       The following options are supported by FFmpeg's flac encoder.

       compression_level
           Sets the compression level, which chooses defaults for many other
           options if they are not set explicitly. Valid values are from 0 to
           12, 5 is the default.

       frame_size
           Sets the size of the frames in samples per channel.

       lpc_coeff_precision
           Sets the LPC coefficient precision, valid values are from 1 to 15,
           15 is the default.

       lpc_type
           Sets the first stage LPC algorithm

           none
               LPC is not used

           fixed
               fixed LPC coefficients

           levinson
           cholesky
       lpc_passes
           Number of passes to use for Cholesky factorization during LPC
           analysis

       min_partition_order
           The minimum partition order

       max_partition_order
           The maximum partition order

       prediction_order_method
           estimation
           2level
           4level
           8level
           search
               Bruteforce search

           log
       ch_mode
           Channel mode

           auto
               The mode is chosen automatically for each frame

           indep
               Channels are independently coded

           left_side
           right_side
           mid_side
       exact_rice_parameters
           Chooses if rice parameters are calculated exactly or approximately.
           if set to 1 then they are chosen exactly, which slows the code down
           slightly and improves compression slightly.

       multi_dim_quant
           Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC
           algorithm is applied after the first stage to finetune the
           coefficients. This is quite slow and slightly improves compression.

   opus
       Opus encoder.

       This is a native FFmpeg encoder for the Opus format. Currently its in
       development and only implements the CELT part of the codec. Its quality
       is usually worse and at best is equal to the libopus encoder.

       Options

       b   Set bit rate in bits/s. If unspecified it uses the number of
           channels and the layout to make a good guess.

       opus_delay
           Sets the maximum delay in milliseconds. Lower delays than 20ms will
           very quickly decrease quality.

   libfdk_aac
       libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.

       The libfdk-aac library is based on the Fraunhofer FDK AAC code from the
       Android project.

       Requires the presence of the libfdk-aac headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libfdk-aac". The library is also incompatible with GPL, so if
       you allow the use of GPL, you should configure with "--enable-gpl
       --enable-nonfree --enable-libfdk-aac".

       This encoder has support for the AAC-HE profiles.

       VBR encoding, enabled through the vbr or flags +qscale options, is
       experimental and only works with some combinations of parameters.

       Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3
       or higher.

       For more information see the fdk-aac project at
       <http://sourceforge.net/p/opencore-amr/fdk-aac/>.

       Options

       The following options are mapped on the shared FFmpeg codec options.

       b   Set bit rate in bits/s. If the bitrate is not explicitly specified,
           it is automatically set to a suitable value depending on the
           selected profile.

           In case VBR mode is enabled the option is ignored.

       ar  Set audio sampling rate (in Hz).

       channels
           Set the number of audio channels.

       flags +qscale
           Enable fixed quality, VBR (Variable Bit Rate) mode.  Note that VBR
           is implicitly enabled when the vbr value is positive.

       cutoff
           Set cutoff frequency. If not specified (or explicitly set to 0) it
           will use a value automatically computed by the library. Default
           value is 0.

       profile
           Set audio profile.

           The following profiles are recognized:

           aac_low
               Low Complexity AAC (LC)

           aac_he
               High Efficiency AAC (HE-AAC)

           aac_he_v2
               High Efficiency AAC version 2 (HE-AACv2)

           aac_ld
               Low Delay AAC (LD)

           aac_eld
               Enhanced Low Delay AAC (ELD)

           If not specified it is set to aac_low.

       The following are private options of the libfdk_aac encoder.

       afterburner
           Enable afterburner feature if set to 1, disabled if set to 0. This
           improves the quality but also the required processing power.

           Default value is 1.

       eld_sbr
           Enable SBR (Spectral Band Replication) for ELD if set to 1,
           disabled if set to 0.

           Default value is 0.

       eld_v2
           Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if
           set to 1, disabled if set to 0.

           Note that option is available when fdk-aac version
           (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) >
           (4.0.0).

           Default value is 0.

       signaling
           Set SBR/PS signaling style.

           It can assume one of the following values:

           default
               choose signaling implicitly (explicit hierarchical by default,
               implicit if global header is disabled)

           implicit
               implicit backwards compatible signaling

           explicit_sbr
               explicit SBR, implicit PS signaling

           explicit_hierarchical
               explicit hierarchical signaling

           Default value is default.

       latm
           Output LATM/LOAS encapsulated data if set to 1, disabled if set to
           0.

           Default value is 0.

       header_period
           Set StreamMuxConfig and PCE repetition period (in frames) for
           sending in-band configuration buffers within LATM/LOAS transport
           layer.

           Must be a 16-bits non-negative integer.

           Default value is 0.

       vbr Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
           good) and 5 is highest quality. A value of 0 will disable VBR, and
           CBR (Constant Bit Rate) is enabled.

           Currently only the aac_low profile supports VBR encoding.

           VBR modes 1-5 correspond to roughly the following average bit
           rates:

           1   32 kbps/channel

           2   40 kbps/channel

           3   48-56 kbps/channel

           4   64 kbps/channel

           5   about 80-96 kbps/channel

           Default value is 0.

       Examples

       o   Use ffmpeg to convert an audio file to VBR AAC in an M4A (MP4)
           container:

                   ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a

       o   Use ffmpeg to convert an audio file to CBR 64k kbps AAC, using the
           High-Efficiency AAC profile:

                   ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a

   libmp3lame
       LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.

       Requires the presence of the libmp3lame headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libmp3lame".

       See libshine for a fixed-point MP3 encoder, although with a lower
       quality.

       Options

       The following options are supported by the libmp3lame wrapper. The
       lame-equivalent of the options are listed in parentheses.

       b (-b)
           Set bitrate expressed in bits/s for CBR or ABR. LAME "bitrate" is
           expressed in kilobits/s.

       q (-V)
           Set constant quality setting for VBR. This option is valid only
           using the ffmpeg command-line tool. For library interface users,
           use global_quality.

       compression_level (-q)
           Set algorithm quality. Valid arguments are integers in the 0-9
           range, with 0 meaning highest quality but slowest, and 9 meaning
           fastest while producing the worst quality.

       cutoff (--lowpass)
           Set lowpass cutoff frequency. If unspecified, the encoder
           dynamically adjusts the cutoff.

       reservoir
           Enable use of bit reservoir when set to 1. Default value is 1. LAME
           has this enabled by default, but can be overridden by use --nores
           option.

       joint_stereo (-m j)
           Enable the encoder to use (on a frame by frame basis) either L/R
           stereo or mid/side stereo. Default value is 1.

       abr (--abr)
           Enable the encoder to use ABR when set to 1. The lame --abr sets
           the target bitrate, while this options only tells FFmpeg to use ABR
           still relies on b to set bitrate.

   libopencore-amrnb
       OpenCORE Adaptive Multi-Rate Narrowband encoder.

       Requires the presence of the libopencore-amrnb headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libopencore-amrnb --enable-version3".

       This is a mono-only encoder. Officially it only supports 8000Hz sample
       rate, but you can override it by setting strict to unofficial or lower.

       Options

       b   Set bitrate in bits per second. Only the following bitrates are
           supported, otherwise libavcodec will round to the nearest valid
           bitrate.

           4750
           5150
           5900
           6700
           7400
           7950
           10200
           12200
       dtx Allow discontinuous transmission (generate comfort noise) when set
           to 1. The default value is 0 (disabled).

   libopus
       libopus Opus Interactive Audio Codec encoder wrapper.

       Requires the presence of the libopus headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libopus".

       Option Mapping

       Most libopus options are modelled after the opusenc utility from opus-
       tools. The following is an option mapping chart describing options
       supported by the libopus wrapper, and their opusenc-equivalent in
       parentheses.

       b (bitrate)
           Set the bit rate in bits/s.  FFmpeg's b option is expressed in
           bits/s, while opusenc's bitrate in kilobits/s.

       vbr (vbr, hard-cbr, and cvbr)
           Set VBR mode. The FFmpeg vbr option has the following valid
           arguments, with the opusenc equivalent options in parentheses:

           off (hard-cbr)
               Use constant bit rate encoding.

           on (vbr)
               Use variable bit rate encoding (the default).

           constrained (cvbr)
               Use constrained variable bit rate encoding.

       compression_level (comp)
           Set encoding algorithm complexity. Valid options are integers in
           the 0-10 range. 0 gives the fastest encodes but lower quality,
           while 10 gives the highest quality but slowest encoding. The
           default is 10.

       frame_duration (framesize)
           Set maximum frame size, or duration of a frame in milliseconds. The
           argument must be exactly the following: 2.5, 5, 10, 20, 40, 60.
           Smaller frame sizes achieve lower latency but less quality at a
           given bitrate.  Sizes greater than 20ms are only interesting at
           fairly low bitrates.  The default is 20ms.

       packet_loss (expect-loss)
           Set expected packet loss percentage. The default is 0.

       fec (n/a)
           Enable inband forward error correction. packet_loss must be non-
           zero to take advantage - frequency of FEC 'side-data' is
           proportional to expected packet loss.  Default is disabled.

       application (N.A.)
           Set intended application type. Valid options are listed below:

           voip
               Favor improved speech intelligibility.

           audio
               Favor faithfulness to the input (the default).

           lowdelay
               Restrict to only the lowest delay modes.

       cutoff (N.A.)
           Set cutoff bandwidth in Hz. The argument must be exactly one of the
           following: 4000, 6000, 8000, 12000, or 20000, corresponding to
           narrowband, mediumband, wideband, super wideband, and fullband
           respectively. The default is 0 (cutoff disabled).

       mapping_family (mapping_family)
           Set channel mapping family to be used by the encoder. The default
           value of -1 uses mapping family 0 for mono and stereo inputs, and
           mapping family 1 otherwise. The default also disables the surround
           masking and LFE bandwidth optimzations in libopus, and requires
           that the input contains 8 channels or fewer.

           Other values include 0 for mono and stereo, 1 for surround sound
           with masking and LFE bandwidth optimizations, and 255 for
           independent streams with an unspecified channel layout.

       apply_phase_inv (N.A.) (requires libopus >= 1.2)
           If set to 0, disables the use of phase inversion for intensity
           stereo, improving the quality of mono downmixes, but slightly
           reducing normal stereo quality. The default is 1 (phase inversion
           enabled).

   libshine
       Shine Fixed-Point MP3 encoder wrapper.

       Shine is a fixed-point MP3 encoder. It has a far better performance on
       platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
       However, as it is more targeted on performance than quality, it is not
       on par with LAME and other production-grade encoders quality-wise.
       Also, according to the project's homepage, this encoder may not be free
       of bugs as the code was written a long time ago and the project was
       dead for at least 5 years.

       This encoder only supports stereo and mono input. This is also CBR-
       only.

       The original project (last updated in early 2007) is at
       <http://sourceforge.net/projects/libshine-fxp/>. We only support the
       updated fork by the Savonet/Liquidsoap project at
       <https://github.com/savonet/shine>.

       Requires the presence of the libshine headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libshine".

       See also libmp3lame.

       Options

       The following options are supported by the libshine wrapper. The
       shineenc-equivalent of the options are listed in parentheses.

       b (-b)
           Set bitrate expressed in bits/s for CBR. shineenc -b option is
           expressed in kilobits/s.

   libtwolame
       TwoLAME MP2 encoder wrapper.

       Requires the presence of the libtwolame headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libtwolame".

       Options

       The following options are supported by the libtwolame wrapper. The
       twolame-equivalent options follow the FFmpeg ones and are in
       parentheses.

       b (-b)
           Set bitrate expressed in bits/s for CBR. twolame b option is
           expressed in kilobits/s. Default value is 128k.

       q (-V)
           Set quality for experimental VBR support. Maximum value range is
           from -50 to 50, useful range is from -10 to 10. The higher the
           value, the better the quality. This option is valid only using the
           ffmpeg command-line tool. For library interface users, use
           global_quality.

       mode (--mode)
           Set the mode of the resulting audio. Possible values:

           auto
               Choose mode automatically based on the input. This is the
               default.

           stereo
               Stereo

           joint_stereo
               Joint stereo

           dual_channel
               Dual channel

           mono
               Mono

       psymodel (--psyc-mode)
           Set psychoacoustic model to use in encoding. The argument must be
           an integer between -1 and 4, inclusive. The higher the value, the
           better the quality. The default value is 3.

       energy_levels (--energy)
           Enable energy levels extensions when set to 1. The default value is
           0 (disabled).

       error_protection (--protect)
           Enable CRC error protection when set to 1. The default value is 0
           (disabled).

       copyright (--copyright)
           Set MPEG audio copyright flag when set to 1. The default value is 0
           (disabled).

       original (--original)
           Set MPEG audio original flag when set to 1. The default value is 0
           (disabled).

   libvo-amrwbenc
       VisualOn Adaptive Multi-Rate Wideband encoder.

       Requires the presence of the libvo-amrwbenc headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libvo-amrwbenc --enable-version3".

       This is a mono-only encoder. Officially it only supports 16000Hz sample
       rate, but you can override it by setting strict to unofficial or lower.

       Options

       b   Set bitrate in bits/s. Only the following bitrates are supported,
           otherwise libavcodec will round to the nearest valid bitrate.

           6600
           8850
           12650
           14250
           15850
           18250
           19850
           23050
           23850
       dtx Allow discontinuous transmission (generate comfort noise) when set
           to 1. The default value is 0 (disabled).

   libvorbis
       libvorbis encoder wrapper.

       Requires the presence of the libvorbisenc headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libvorbis".

       Options

       The following options are supported by the libvorbis wrapper. The
       oggenc-equivalent of the options are listed in parentheses.

       To get a more accurate and extensive documentation of the libvorbis
       options, consult the libvorbisenc's and oggenc's documentations.  See
       <http://xiph.org/vorbis/>, <http://wiki.xiph.org/Vorbis-tools>, and
       oggenc(1).

       b (-b)
           Set bitrate expressed in bits/s for ABR. oggenc -b is expressed in
           kilobits/s.

       q (-q)
           Set constant quality setting for VBR. The value should be a float
           number in the range of -1.0 to 10.0. The higher the value, the
           better the quality. The default value is 3.0.

           This option is valid only using the ffmpeg command-line tool.  For
           library interface users, use global_quality.

       cutoff (--advanced-encode-option lowpass_frequency=N)
           Set cutoff bandwidth in Hz, a value of 0 disables cutoff. oggenc's
           related option is expressed in kHz. The default value is 0 (cutoff
           disabled).

       minrate (-m)
           Set minimum bitrate expressed in bits/s. oggenc -m is expressed in
           kilobits/s.

       maxrate (-M)
           Set maximum bitrate expressed in bits/s. oggenc -M is expressed in
           kilobits/s. This only has effect on ABR mode.

       iblock (--advanced-encode-option impulse_noisetune=N)
           Set noise floor bias for impulse blocks. The value is a float
           number from -15.0 to 0.0. A negative bias instructs the encoder to
           pay special attention to the crispness of transients in the encoded
           audio. The tradeoff for better transient response is a higher
           bitrate.

   mjpeg
       Motion JPEG encoder.

       Options

       huffman
           Set the huffman encoding strategy. Possible values:

           default
               Use the default huffman tables. This is the default strategy.

           optimal
               Compute and use optimal huffman tables.

   wavpack
       WavPack lossless audio encoder.

       Options

       The equivalent options for wavpack command line utility are listed in
       parentheses.

       Shared options

       The following shared options are effective for this encoder. Only
       special notes about this particular encoder will be documented here.
       For the general meaning of the options, see the Codec Options chapter.

       frame_size (--blocksize)
           For this encoder, the range for this option is between 128 and
           131072. Default is automatically decided based on sample rate and
           number of channel.

           For the complete formula of calculating default, see
           libavcodec/wavpackenc.c.

       compression_level (-f, -h, -hh, and -x)

       Private options

       joint_stereo (-j)
           Set whether to enable joint stereo. Valid values are:

           on (1)
               Force mid/side audio encoding.

           off (0)
               Force left/right audio encoding.

           auto
               Let the encoder decide automatically.

       optimize_mono
           Set whether to enable optimization for mono. This option is only
           effective for non-mono streams. Available values:

           on  enabled

           off disabled


VIDEO ENCODERS

       A description of some of the currently available video encoders
       follows.

   GIF
       GIF image/animation encoder.

       Options

       gifflags integer
           Sets the flags used for GIF encoding.

           offsetting
               Enables picture offsetting.

               Default is enabled.

           transdiff
               Enables transparency detection between frames.

               Default is enabled.

       gifimage integer
           Enables encoding one full GIF image per frame, rather than an
           animated GIF.

           Default value is 0.

       global_palette integer
           Writes a palette to the global GIF header where feasible.

           If disabled, every frame will always have a palette written, even
           if there is a global palette supplied.

           Default value is 1.

   Hap
       Vidvox Hap video encoder.

       Options

       format integer
           Specifies the Hap format to encode.

           hap
           hap_alpha
           hap_q

           Default value is hap.

       chunks integer
           Specifies the number of chunks to split frames into, between 1 and
           64. This permits multithreaded decoding of large frames,
           potentially at the cost of data-rate. The encoder may modify this
           value to divide frames evenly.

           Default value is 1.

       compressor integer
           Specifies the second-stage compressor to use. If set to none,
           chunks will be limited to 1, as chunked uncompressed frames offer
           no benefit.

           none
           snappy

           Default value is snappy.

   jpeg2000
       The native jpeg 2000 encoder is lossy by default, the "-q:v" option can
       be used to set the encoding quality. Lossless encoding can be selected
       with "-pred 1".

       Options

       format integer
           Can be set to either "j2k" or "jp2" (the default) that makes it
           possible to store non-rgb pix_fmts.

       tile_width integer
           Sets tile width. Range is 1 to 1073741824. Default is 256.

       tile_height integer
           Sets tile height. Range is 1 to 1073741824. Default is 256.

       pred integer
           Allows setting the discrete wavelet transform (DWT) type

           dwt97int (Lossy)
           dwt53 (Lossless)

           Default is "dwt97int"

       sop boolean
           Enable this to add SOP marker at the start of each packet. Disabled
           by default.

       eph boolean
           Enable this to add EPH marker at the end of each packet header.
           Disabled by default.

       prog integer
           Sets the progression order to be used by the encoder.  Possible
           values are:

           lrcp
           rlcp
           rpcl
           pcrl
           cprl

           Set to "lrcp" by default.

       layer_rates string
           By default, when this option is not used, compression is done using
           the quality metric.  This option allows for compression using
           compression ratio. The compression ratio for each level could be
           specified. The compression ratio of a layer "l" species the what
           ratio of total file size is contained in the first "l" layers.

           Example usage:

                   ffmpeg -i input.bmp -c:v jpeg2000 -layer_rates "100,10,1" output.j2k

           This would compress the image to contain 3 layers, where the data
           contained in the first layer would be compressed by 1000 times,
           compressed by 100 in the first two layers, and shall contain all
           data while using all 3 layers.

   librav1e
       rav1e AV1 encoder wrapper.

       Requires the presence of the rav1e headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-librav1e".

       Options

       qmax
           Sets the maximum quantizer to use when using bitrate mode.

       qmin
           Sets the minimum quantizer to use when using bitrate mode.

       qp  Uses quantizer mode to encode at the given quantizer (0-255).

       speed
           Selects the speed preset (0-10) to encode with.

       tiles
           Selects how many tiles to encode with.

       tile-rows
           Selects how many rows of tiles to encode with.

       tile-columns
           Selects how many columns of tiles to encode with.

       rav1e-params
           Set rav1e options using a list of key=value pairs separated by ":".
           See rav1e --help for a list of options.

           For example to specify librav1e encoding options with
           -rav1e-params:

                   ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4

   libaom-av1
       libaom AV1 encoder wrapper.

       Requires the presence of the libaom headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libaom".

       Options

       The wrapper supports the following standard libavcodec options:

       b   Set bitrate target in bits/second.  By default this will use
           variable-bitrate mode.  If maxrate and minrate are also set to the
           same value then it will use constant-bitrate mode, otherwise if crf
           is set as well then it will use constrained-quality mode.

       g keyint_min
           Set key frame placement.  The GOP size sets the maximum distance
           between key frames; if zero the output stream will be intra-only.
           The minimum distance is ignored unless it is the same as the GOP
           size, in which case key frames will always appear at a fixed
           interval.  Not set by default, so without this option the library
           has completely free choice about where to place key frames.

       qmin qmax
           Set minimum/maximum quantisation values.  Valid range is from 0 to
           63 (warning: this does not match the quantiser values actually used
           by AV1 - divide by four to map real quantiser values to this
           range).  Defaults to min/max (no constraint).

       minrate maxrate bufsize rc_init_occupancy
           Set rate control buffering parameters.  Not used if not set -
           defaults to unconstrained variable bitrate.

       threads
           Set the number of threads to use while encoding.  This may require
           the tiles or row-mt options to also be set to actually use the
           specified number of threads fully. Defaults to the number of
           hardware threads supported by the host machine.

       profile
           Set the encoding profile.  Defaults to using the profile which
           matches the bit depth and chroma subsampling of the input.

       The wrapper also has some specific options:

       cpu-used
           Set the quality/encoding speed tradeoff.  Valid range is from 0 to
           8, higher numbers indicating greater speed and lower quality.  The
           default value is 1, which will be slow and high quality.

       auto-alt-ref
           Enable use of alternate reference frames.  Defaults to the internal
           default of the library.

       arnr-max-frames (frames)
           Set altref noise reduction max frame count. Default is -1.

       arnr-strength (strength)
           Set altref noise reduction filter strength. Range is -1 to 6.
           Default is -1.

       aq-mode (aq-mode)
           Set adaptive quantization mode. Possible values:

           none (0)
               Disabled.

           variance (1)
               Variance-based.

           complexity (2)
               Complexity-based.

           cyclic (3)
               Cyclic refresh.

       tune (tune)
           Set the distortion metric the encoder is tuned with. Default is
           "psnr".

           psnr (0)
           ssim (1)
       lag-in-frames
           Set the maximum number of frames which the encoder may keep in
           flight at any one time for lookahead purposes.  Defaults to the
           internal default of the library.

       error-resilience
           Enable error resilience features:

           default
               Improve resilience against losses of whole frames.

           Not enabled by default.

       crf Set the quality/size tradeoff for constant-quality (no bitrate
           target) and constrained-quality (with maximum bitrate target)
           modes. Valid range is 0 to 63, higher numbers indicating lower
           quality and smaller output size.  Only used if set; by default only
           the bitrate target is used.

       static-thresh
           Set a change threshold on blocks below which they will be skipped
           by the encoder.  Defined in arbitrary units as a nonnegative
           integer, defaulting to zero (no blocks are skipped).

       drop-threshold
           Set a threshold for dropping frames when close to rate control
           bounds.  Defined as a percentage of the target buffer - when the
           rate control buffer falls below this percentage, frames will be
           dropped until it has refilled above the threshold.  Defaults to
           zero (no frames are dropped).

       denoise-noise-level (level)
           Amount of noise to be removed for grain synthesis. Grain synthesis
           is disabled if this option is not set or set to 0.

       denoise-block-size (pixels)
           Block size used for denoising for grain synthesis. If not set, AV1
           codec uses the default value of 32.

       undershoot-pct (pct)
           Set datarate undershoot (min) percentage of the target bitrate.
           Range is -1 to 100.  Default is -1.

       overshoot-pct (pct)
           Set datarate overshoot (max) percentage of the target bitrate.
           Range is -1 to 1000.  Default is -1.

       minsection-pct (pct)
           Minimum percentage variation of the GOP bitrate from the target
           bitrate. If minsection-pct is not set, the libaomenc wrapper
           computes it as follows: "(minrate * 100 / bitrate)".  Range is -1
           to 100. Default is -1 (unset).

       maxsection-pct (pct)
           Maximum percentage variation of the GOP bitrate from the target
           bitrate. If maxsection-pct is not set, the libaomenc wrapper
           computes it as follows: "(maxrate * 100 / bitrate)".  Range is -1
           to 5000. Default is -1 (unset).

       frame-parallel (boolean)
           Enable frame parallel decodability features. Default is true.

       tiles
           Set the number of tiles to encode the input video with, as columns
           x rows.  Larger numbers allow greater parallelism in both encoding
           and decoding, but may decrease coding efficiency.  Defaults to the
           minimum number of tiles required by the size of the input video
           (this is 1x1 (that is, a single tile) for sizes up to and including
           4K).

       tile-columns tile-rows
           Set the number of tiles as log2 of the number of tile rows and
           columns.  Provided for compatibility with libvpx/VP9.

       row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
           Enable row based multi-threading. Disabled by default.

       enable-cdef (boolean)
           Enable Constrained Directional Enhancement Filter. The libaom-av1
           encoder enables CDEF by default.

       enable-restoration (boolean)
           Enable Loop Restoration Filter. Default is true for libaom-av1.

       enable-global-motion (boolean)
           Enable the use of global motion for block prediction. Default is
           true.

       enable-intrabc (boolean)
           Enable block copy mode for intra block prediction. This mode is
           useful for screen content. Default is true.

       enable-rect-partitions (boolean) (Requires libaom >= v2.0.0)
           Enable rectangular partitions. Default is true.

       enable-1to4-partitions (boolean) (Requires libaom >= v2.0.0)
           Enable 1:4/4:1 partitions. Default is true.

       enable-ab-partitions (boolean) (Requires libaom >= v2.0.0)
           Enable AB shape partitions. Default is true.

       enable-angle-delta (boolean) (Requires libaom >= v2.0.0)
           Enable angle delta intra prediction. Default is true.

       enable-cfl-intra (boolean) (Requires libaom >= v2.0.0)
           Enable chroma predicted from luma intra prediction. Default is
           true.

       enable-filter-intra (boolean) (Requires libaom >= v2.0.0)
           Enable filter intra predictor. Default is true.

       enable-intra-edge-filter (boolean) (Requires libaom >= v2.0.0)
           Enable intra edge filter. Default is true.

       enable-smooth-intra (boolean) (Requires libaom >= v2.0.0)
           Enable smooth intra prediction mode. Default is true.

       enable-paeth-intra (boolean) (Requires libaom >= v2.0.0)
           Enable paeth predictor in intra prediction. Default is true.

       enable-palette (boolean) (Requires libaom >= v2.0.0)
           Enable palette prediction mode. Default is true.

       enable-flip-idtx (boolean) (Requires libaom >= v2.0.0)
           Enable extended transform type, including FLIPADST_DCT,
           DCT_FLIPADST, FLIPADST_FLIPADST, ADST_FLIPADST, FLIPADST_ADST,
           IDTX, V_DCT, H_DCT, V_ADST, H_ADST, V_FLIPADST, H_FLIPADST. Default
           is true.

       enable-tx64 (boolean) (Requires libaom >= v2.0.0)
           Enable 64-pt transform. Default is true.

       reduced-tx-type-set (boolean) (Requires libaom >= v2.0.0)
           Use reduced set of transform types. Default is false.

       use-intra-dct-only (boolean) (Requires libaom >= v2.0.0)
           Use DCT only for INTRA modes. Default is false.

       use-inter-dct-only (boolean) (Requires libaom >= v2.0.0)
           Use DCT only for INTER modes. Default is false.

       use-intra-default-tx-only (boolean) (Requires libaom >= v2.0.0)
           Use Default-transform only for INTRA modes. Default is false.

       enable-ref-frame-mvs (boolean) (Requires libaom >= v2.0.0)
           Enable temporal mv prediction. Default is true.

       enable-reduced-reference-set (boolean) (Requires libaom >= v2.0.0)
           Use reduced set of single and compound references. Default is
           false.

       enable-obmc (boolean) (Requires libaom >= v2.0.0)
           Enable obmc. Default is true.

       enable-dual-filter (boolean) (Requires libaom >= v2.0.0)
           Enable dual filter. Default is true.

       enable-diff-wtd-comp (boolean) (Requires libaom >= v2.0.0)
           Enable difference-weighted compound. Default is true.

       enable-dist-wtd-comp (boolean) (Requires libaom >= v2.0.0)
           Enable distance-weighted compound. Default is true.

       enable-onesided-comp (boolean) (Requires libaom >= v2.0.0)
           Enable one sided compound. Default is true.

       enable-interinter-wedge (boolean) (Requires libaom >= v2.0.0)
           Enable interinter wedge compound. Default is true.

       enable-interintra-wedge (boolean) (Requires libaom >= v2.0.0)
           Enable interintra wedge compound. Default is true.

       enable-masked-comp (boolean) (Requires libaom >= v2.0.0)
           Enable masked compound. Default is true.

       enable-interintra-comp (boolean) (Requires libaom >= v2.0.0)
           Enable interintra compound. Default is true.

       enable-smooth-interintra (boolean) (Requires libaom >= v2.0.0)
           Enable smooth interintra mode. Default is true.

       aom-params
           Set libaom options using a list of key=value pairs separated by
           ":". For a list of supported options, see aomenc --help under the
           section "AV1 Specific Options".

           For example to specify libaom encoding options with -aom-params:

                   ffmpeg -i input -c:v libaom-av1 -b:v 500K -aom-params tune=psnr:enable-tpl-model=1 output.mp4

   libsvtav1
       SVT-AV1 encoder wrapper.

       Requires the presence of the SVT-AV1 headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libsvtav1".

       Options

       profile
           Set the encoding profile.

       level
           Set the operating point level.

       tier
           Set the operating point tier.

       rc  Set the rate control mode to use.

           Possible modes:

           cqp Constant quantizer: use fixed values of qindex (dependent on
               the frame type) throughout the stream.  This mode is the
               default.

           vbr Variable bitrate: use a target bitrate for the whole stream.

           cvbr
               Constrained variable bitrate: use a target bitrate for each
               GOP.

       qmax
           Set the maximum quantizer to use when using a bitrate mode.

       qmin
           Set the minimum quantizer to use when using a bitrate mode.

       qp  Set the quantizer used in cqp rate control mode (0-63).

       sc_detection
           Enable scene change detection.

       la_depth
           Set number of frames to look ahead (0-120).

       preset
           Set the quality-speed tradeoff, in the range 0 to 8.  Higher values
           are faster but lower quality.  Defaults to 8 (highest speed).

       tile_rows
           Set log2 of the number of rows of tiles to use (0-6).

       tile_columns
           Set log2 of the number of columns of tiles to use (0-4).

   libkvazaar
       Kvazaar H.265/HEVC encoder.

       Requires the presence of the libkvazaar headers and library during
       configuration. You need to explicitly configure the build with
       --enable-libkvazaar.

       Options

       b   Set target video bitrate in bit/s and enable rate control.

       kvazaar-params
           Set kvazaar parameters as a list of name=value pairs separated by
           commas (,). See kvazaar documentation for a list of options.

   libopenh264
       Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.

       This encoder requires the presence of the libopenh264 headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libopenh264". The library is detected using pkg-
       config.

       For more information about the library see <http://www.openh264.org>.

       Options

       The following FFmpeg global options affect the configurations of the
       libopenh264 encoder.

       b   Set the bitrate (as a number of bits per second).

       g   Set the GOP size.

       maxrate
           Set the max bitrate (as a number of bits per second).

       flags +global_header
           Set global header in the bitstream.

       slices
           Set the number of slices, used in parallelized encoding. Default
           value is 0. This is only used when slice_mode is set to fixed.

       slice_mode
           Set slice mode. Can assume one of the following possible values:

           fixed
               a fixed number of slices

           rowmb
               one slice per row of macroblocks

           auto
               automatic number of slices according to number of threads

           dyn dynamic slicing

           Default value is auto.

       loopfilter
           Enable loop filter, if set to 1 (automatically enabled). To disable
           set a value of 0.

       profile
           Set profile restrictions. If set to the value of main enable CABAC
           (set the "SEncParamExt.iEntropyCodingModeFlag" flag to 1).

       max_nal_size
           Set maximum NAL size in bytes.

       allow_skip_frames
           Allow skipping frames to hit the target bitrate if set to 1.

   libtheora
       libtheora Theora encoder wrapper.

       Requires the presence of the libtheora headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libtheora".

       For more information about the libtheora project see
       <http://www.theora.org/>.

       Options

       The following global options are mapped to internal libtheora options
       which affect the quality and the bitrate of the encoded stream.

       b   Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode.
           In case VBR (Variable Bit Rate) mode is enabled this option is
           ignored.

       flags
           Used to enable constant quality mode (VBR) encoding through the
           qscale flag, and to enable the "pass1" and "pass2" modes.

       g   Set the GOP size.

       global_quality
           Set the global quality as an integer in lambda units.

           Only relevant when VBR mode is enabled with "flags +qscale". The
           value is converted to QP units by dividing it by "FF_QP2LAMBDA",
           clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
           value in the native libtheora range [0-63]. A higher value
           corresponds to a higher quality.

       q   Enable VBR mode when set to a non-negative value, and set constant
           quality value as a double floating point value in QP units.

           The value is clipped in the [0-10] range, and then multiplied by
           6.3 to get a value in the native libtheora range [0-63].

           This option is valid only using the ffmpeg command-line tool. For
           library interface users, use global_quality.

       Examples

       o   Set maximum constant quality (VBR) encoding with ffmpeg:

                   ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg

       o   Use ffmpeg to convert a CBR 1000 kbps Theora video stream:

                   ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg

   libvpx
       VP8/VP9 format supported through libvpx.

       Requires the presence of the libvpx headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libvpx".

       Options

       The following options are supported by the libvpx wrapper. The
       vpxenc-equivalent options or values are listed in parentheses for easy
       migration.

       To reduce the duplication of documentation, only the private options
       and some others requiring special attention are documented here. For
       the documentation of the undocumented generic options, see the Codec
       Options chapter.

       To get more documentation of the libvpx options, invoke the command
       ffmpeg -h encoder=libvpx, ffmpeg -h encoder=libvpx-vp9 or vpxenc
       --help. Further information is available in the libvpx API
       documentation.

       b (target-bitrate)
           Set bitrate in bits/s. Note that FFmpeg's b option is expressed in
           bits/s, while vpxenc's target-bitrate is in kilobits/s.

       g (kf-max-dist)
       keyint_min (kf-min-dist)
       qmin (min-q)
       qmax (max-q)
       bufsize (buf-sz, buf-optimal-sz)
           Set ratecontrol buffer size (in bits). Note vpxenc's options are
           specified in milliseconds, the libvpx wrapper converts this value
           as follows: "buf-sz = bufsize * 1000 / bitrate", "buf-optimal-sz =
           bufsize * 1000 / bitrate * 5 / 6".

       rc_init_occupancy (buf-initial-sz)
           Set number of bits which should be loaded into the rc buffer before
           decoding starts. Note vpxenc's option is specified in milliseconds,
           the libvpx wrapper converts this value as follows:
           "rc_init_occupancy * 1000 / bitrate".

       undershoot-pct
           Set datarate undershoot (min) percentage of the target bitrate.

       overshoot-pct
           Set datarate overshoot (max) percentage of the target bitrate.

       skip_threshold (drop-frame)
       qcomp (bias-pct)
       maxrate (maxsection-pct)
           Set GOP max bitrate in bits/s. Note vpxenc's option is specified as
           a percentage of the target bitrate, the libvpx wrapper converts
           this value as follows: "(maxrate * 100 / bitrate)".

       minrate (minsection-pct)
           Set GOP min bitrate in bits/s. Note vpxenc's option is specified as
           a percentage of the target bitrate, the libvpx wrapper converts
           this value as follows: "(minrate * 100 / bitrate)".

       minrate, maxrate, b end-usage=cbr
           "(minrate == maxrate == bitrate)".

       crf (end-usage=cq, cq-level)
       tune (tune)
           psnr (psnr)
           ssim (ssim)
       quality, deadline (deadline)
           best
               Use best quality deadline. Poorly named and quite slow, this
               option should be avoided as it may give worse quality output
               than good.

           good
               Use good quality deadline. This is a good trade-off between
               speed and quality when used with the cpu-used option.

           realtime
               Use realtime quality deadline.

       speed, cpu-used (cpu-used)
           Set quality/speed ratio modifier. Higher values speed up the encode
           at the cost of quality.

       nr (noise-sensitivity)
       static-thresh
           Set a change threshold on blocks below which they will be skipped
           by the encoder.

       slices (token-parts)
           Note that FFmpeg's slices option gives the total number of
           partitions, while vpxenc's token-parts is given as
           "log2(partitions)".

       max-intra-rate
           Set maximum I-frame bitrate as a percentage of the target bitrate.
           A value of 0 means unlimited.

       force_key_frames
           "VPX_EFLAG_FORCE_KF"

       Alternate reference frame related
           auto-alt-ref
               Enable use of alternate reference frames (2-pass only).  Values
               greater than 1 enable multi-layer alternate reference frames
               (VP9 only).

           arnr-maxframes
               Set altref noise reduction max frame count.

           arnr-type
               Set altref noise reduction filter type: backward, forward,
               centered.

           arnr-strength
               Set altref noise reduction filter strength.

           rc-lookahead, lag-in-frames (lag-in-frames)
               Set number of frames to look ahead for frametype and
               ratecontrol.

       error-resilient
           Enable error resiliency features.

       sharpness integer
           Increase sharpness at the expense of lower PSNR.  The valid range
           is [0, 7].

       ts-parameters
           Sets the temporal scalability configuration using a :-separated
           list of key=value pairs. For example, to specify temporal
           scalability parameters with "ffmpeg":

                   ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
                   ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
                   ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT

           Below is a brief explanation of each of the parameters, please
           refer to "struct vpx_codec_enc_cfg" in "vpx/vpx_encoder.h" for more
           details.

           ts_number_layers
               Number of temporal coding layers.

           ts_target_bitrate
               Target bitrate for each temporal layer (in kbps).  (bitrate
               should be inclusive of the lower temporal layer).

           ts_rate_decimator
               Frame rate decimation factor for each temporal layer.

           ts_periodicity
               Length of the sequence defining frame temporal layer
               membership.

           ts_layer_id
               Template defining the membership of frames to temporal layers.

           ts_layering_mode
               (optional) Selecting the temporal structure from a set of pre-
               defined temporal layering modes.  Currently supports the
               following options.

               0   No temporal layering flags are provided internally, relies
                   on flags being passed in using "metadata" field in
                   "AVFrame" with following keys.

                   vp8-flags
                       Sets the flags passed into the encoder to indicate the
                       referencing scheme for the current frame.  Refer to
                       function "vpx_codec_encode" in "vpx/vpx_encoder.h" for
                       more details.

                   temporal_id
                       Explicitly sets the temporal id of the current frame to
                       encode.

               2   Two temporal layers. 0-1...

               3   Three temporal layers. 0-2-1-2...; with single reference
                   frame.

               4   Same as option "3", except there is a dependency between
                   the two temporal layer 2 frames within the temporal period.

       VP9-specific options
           lossless
               Enable lossless mode.

           tile-columns
               Set number of tile columns to use. Note this is given as
               "log2(tile_columns)". For example, 8 tile columns would be
               requested by setting the tile-columns option to 3.

           tile-rows
               Set number of tile rows to use. Note this is given as
               "log2(tile_rows)".  For example, 4 tile rows would be requested
               by setting the tile-rows option to 2.

           frame-parallel
               Enable frame parallel decodability features.

           aq-mode
               Set adaptive quantization mode (0: off (default), 1: variance
               2: complexity, 3: cyclic refresh, 4: equator360).

           colorspace color-space
               Set input color space. The VP9 bitstream supports signaling the
               following colorspaces:

               rgb sRGB
               bt709 bt709
               unspecified unknown
               bt470bg bt601
               smpte170m smpte170
               smpte240m smpte240
               bt2020_ncl bt2020
           row-mt boolean
               Enable row based multi-threading.

           tune-content
               Set content type: default (0), screen (1), film (2).

           corpus-complexity
               Corpus VBR mode is a variant of standard VBR where the
               complexity distribution midpoint is passed in rather than
               calculated for a specific clip or chunk.

               The valid range is [0, 10000]. 0 (default) uses standard VBR.

           enable-tpl boolean
               Enable temporal dependency model.

           ref-frame-config
               Using per-frame metadata, set members of the structure
               "vpx_svc_ref_frame_config_t" in "vpx/vp8cx.h" to fine-control
               referencing schemes and frame buffer management.  Use a
               :-separated list of key=value pairs.  For example,

                       av_dict_set(&av_frame->metadata, "ref-frame-config", \
                       "rfc_update_buffer_slot=7:rfc_lst_fb_idx=0:rfc_gld_fb_idx=1:rfc_alt_fb_idx=2:rfc_reference_last=0:rfc_reference_golden=0:rfc_reference_alt_ref=0");

               rfc_update_buffer_slot
                   Indicates the buffer slot number to update

               rfc_update_last
                   Indicates whether to update the LAST frame

               rfc_update_golden
                   Indicates whether to update GOLDEN frame

               rfc_update_alt_ref
                   Indicates whether to update ALT_REF frame

               rfc_lst_fb_idx
                   LAST frame buffer index

               rfc_gld_fb_idx
                   GOLDEN frame buffer index

               rfc_alt_fb_idx
                   ALT_REF frame buffer index

               rfc_reference_last
                   Indicates whether to reference LAST frame

               rfc_reference_golden
                   Indicates whether to reference GOLDEN frame

               rfc_reference_alt_ref
                   Indicates whether to reference ALT_REF frame

               rfc_reference_duration
                   Indicates frame duration

       For more information about libvpx see: <http://www.webmproject.org/>

   libwebp
       libwebp WebP Image encoder wrapper

       libwebp is Google's official encoder for WebP images. It can encode in
       either lossy or lossless mode. Lossy images are essentially a wrapper
       around a VP8 frame. Lossless images are a separate codec developed by
       Google.

       Pixel Format

       Currently, libwebp only supports YUV420 for lossy and RGB for lossless
       due to limitations of the format and libwebp. Alpha is supported for
       either mode.  Because of API limitations, if RGB is passed in when
       encoding lossy or YUV is passed in for encoding lossless, the pixel
       format will automatically be converted using functions from libwebp.
       This is not ideal and is done only for convenience.

       Options

       -lossless boolean
           Enables/Disables use of lossless mode. Default is 0.

       -compression_level integer
           For lossy, this is a quality/speed tradeoff. Higher values give
           better quality for a given size at the cost of increased encoding
           time. For lossless, this is a size/speed tradeoff. Higher values
           give smaller size at the cost of increased encoding time. More
           specifically, it controls the number of extra algorithms and
           compression tools used, and varies the combination of these tools.
           This maps to the method option in libwebp. The valid range is 0 to
           6.  Default is 4.

       -qscale float
           For lossy encoding, this controls image quality, 0 to 100. For
           lossless encoding, this controls the effort and time spent at
           compressing more. The default value is 75. Note that for usage via
           libavcodec, this option is called global_quality and must be
           multiplied by FF_QP2LAMBDA.

       -preset type
           Configuration preset. This does some automatic settings based on
           the general type of the image.

           none
               Do not use a preset.

           default
               Use the encoder default.

           picture
               Digital picture, like portrait, inner shot

           photo
               Outdoor photograph, with natural lighting

           drawing
               Hand or line drawing, with high-contrast details

           icon
               Small-sized colorful images

           text
               Text-like

   libx264, libx264rgb
       x264 H.264/MPEG-4 AVC encoder wrapper.

       This encoder requires the presence of the libx264 headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libx264".

       libx264 supports an impressive number of features, including 8x8 and
       4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
       entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
       for detail retention (adaptive quantization, psy-RD, psy-trellis).

       Many libx264 encoder options are mapped to FFmpeg global codec options,
       while unique encoder options are provided through private options.
       Additionally the x264opts and x264-params private options allows one to
       pass a list of key=value tuples as accepted by the libx264
       "x264_param_parse" function.

       The x264 project website is at
       <http://www.videolan.org/developers/x264.html>.

       The libx264rgb encoder is the same as libx264, except it accepts packed
       RGB pixel formats as input instead of YUV.

       Supported Pixel Formats

       x264 supports 8- to 10-bit color spaces. The exact bit depth is
       controlled at x264's configure time.

       Options

       The following options are supported by the libx264 wrapper. The
       x264-equivalent options or values are listed in parentheses for easy
       migration.

       To reduce the duplication of documentation, only the private options
       and some others requiring special attention are documented here. For
       the documentation of the undocumented generic options, see the Codec
       Options chapter.

       To get a more accurate and extensive documentation of the libx264
       options, invoke the command x264 --fullhelp or consult the libx264
       documentation.

       b (bitrate)
           Set bitrate in bits/s. Note that FFmpeg's b option is expressed in
           bits/s, while x264's bitrate is in kilobits/s.

       bf (bframes)
       g (keyint)
       qmin (qpmin)
           Minimum quantizer scale.

       qmax (qpmax)
           Maximum quantizer scale.

       qdiff (qpstep)
           Maximum difference between quantizer scales.

       qblur (qblur)
           Quantizer curve blur

       qcomp (qcomp)
           Quantizer curve compression factor

       refs (ref)
           Number of reference frames each P-frame can use. The range is from
           0-16.

       sc_threshold (scenecut)
           Sets the threshold for the scene change detection.

       trellis (trellis)
           Performs Trellis quantization to increase efficiency. Enabled by
           default.

       nr  (nr)
       me_range (merange)
           Maximum range of the motion search in pixels.

       me_method (me)
           Set motion estimation method. Possible values in the decreasing
           order of speed:

           dia (dia)
           epzs (dia)
               Diamond search with radius 1 (fastest). epzs is an alias for
               dia.

           hex (hex)
               Hexagonal search with radius 2.

           umh (umh)
               Uneven multi-hexagon search.

           esa (esa)
               Exhaustive search.

           tesa (tesa)
               Hadamard exhaustive search (slowest).

       forced-idr
           Normally, when forcing a I-frame type, the encoder can select any
           type of I-frame. This option forces it to choose an IDR-frame.

       subq (subme)
           Sub-pixel motion estimation method.

       b_strategy (b-adapt)
           Adaptive B-frame placement decision algorithm. Use only on first-
           pass.

       keyint_min (min-keyint)
           Minimum GOP size.

       coder
           Set entropy encoder. Possible values:

           ac  Enable CABAC.

           vlc Enable CAVLC and disable CABAC. It generates the same effect as
               x264's --no-cabac option.

       cmp Set full pixel motion estimation comparison algorithm. Possible
           values:

           chroma
               Enable chroma in motion estimation.

           sad Ignore chroma in motion estimation. It generates the same
               effect as x264's --no-chroma-me option.

       threads (threads)
           Number of encoding threads.

       thread_type
           Set multithreading technique. Possible values:

           slice
               Slice-based multithreading. It generates the same effect as
               x264's --sliced-threads option.

           frame
               Frame-based multithreading.

       flags
           Set encoding flags. It can be used to disable closed GOP and enable
           open GOP by setting it to "-cgop". The result is similar to the
           behavior of x264's --open-gop option.

       rc_init_occupancy (vbv-init)
       preset (preset)
           Set the encoding preset.

       tune (tune)
           Set tuning of the encoding params.

       profile (profile)
           Set profile restrictions.

       fastfirstpass
           Enable fast settings when encoding first pass, when set to 1. When
           set to 0, it has the same effect of x264's --slow-firstpass option.

       crf (crf)
           Set the quality for constant quality mode.

       crf_max (crf-max)
           In CRF mode, prevents VBV from lowering quality beyond this point.

       qp (qp)
           Set constant quantization rate control method parameter.

       aq-mode (aq-mode)
           Set AQ method. Possible values:

           none (0)
               Disabled.

           variance (1)
               Variance AQ (complexity mask).

           autovariance (2)
               Auto-variance AQ (experimental).

       aq-strength (aq-strength)
           Set AQ strength, reduce blocking and blurring in flat and textured
           areas.

       psy Use psychovisual optimizations when set to 1. When set to 0, it has
           the same effect as x264's --no-psy option.

       psy-rd  (psy-rd)
           Set strength of psychovisual optimization, in psy-rd:psy-trellis
           format.

       rc-lookahead (rc-lookahead)
           Set number of frames to look ahead for frametype and ratecontrol.

       weightb
           Enable weighted prediction for B-frames when set to 1. When set to
           0, it has the same effect as x264's --no-weightb option.

       weightp (weightp)
           Set weighted prediction method for P-frames. Possible values:

           none (0)
               Disabled

           simple (1)
               Enable only weighted refs

           smart (2)
               Enable both weighted refs and duplicates

       ssim (ssim)
           Enable calculation and printing SSIM stats after the encoding.

       intra-refresh (intra-refresh)
           Enable the use of Periodic Intra Refresh instead of IDR frames when
           set to 1.

       avcintra-class (class)
           Configure the encoder to generate AVC-Intra.  Valid values are
           50,100 and 200

       bluray-compat (bluray-compat)
           Configure the encoder to be compatible with the bluray standard.
           It is a shorthand for setting "bluray-compat=1 force-cfr=1".

       b-bias (b-bias)
           Set the influence on how often B-frames are used.

       b-pyramid (b-pyramid)
           Set method for keeping of some B-frames as references. Possible
           values:

           none (none)
               Disabled.

           strict (strict)
               Strictly hierarchical pyramid.

           normal (normal)
               Non-strict (not Blu-ray compatible).

       mixed-refs
           Enable the use of one reference per partition, as opposed to one
           reference per macroblock when set to 1. When set to 0, it has the
           same effect as x264's --no-mixed-refs option.

       8x8dct
           Enable adaptive spatial transform (high profile 8x8 transform) when
           set to 1. When set to 0, it has the same effect as x264's
           --no-8x8dct option.

       fast-pskip
           Enable early SKIP detection on P-frames when set to 1. When set to
           0, it has the same effect as x264's --no-fast-pskip option.

       aud (aud)
           Enable use of access unit delimiters when set to 1.

       mbtree
           Enable use macroblock tree ratecontrol when set to 1. When set to
           0, it has the same effect as x264's --no-mbtree option.

       deblock (deblock)
           Set loop filter parameters, in alpha:beta form.

       cplxblur (cplxblur)
           Set fluctuations reduction in QP (before curve compression).

       partitions (partitions)
           Set partitions to consider as a comma-separated list of. Possible
           values in the list:

           p8x8
               8x8 P-frame partition.

           p4x4
               4x4 P-frame partition.

           b8x8
               4x4 B-frame partition.

           i8x8
               8x8 I-frame partition.

           i4x4
               4x4 I-frame partition.  (Enabling p4x4 requires p8x8 to be
               enabled. Enabling i8x8 requires adaptive spatial transform
               (8x8dct option) to be enabled.)

           none (none)
               Do not consider any partitions.

           all (all)
               Consider every partition.

       direct-pred (direct)
           Set direct MV prediction mode. Possible values:

           none (none)
               Disable MV prediction.

           spatial (spatial)
               Enable spatial predicting.

           temporal (temporal)
               Enable temporal predicting.

           auto (auto)
               Automatically decided.

       slice-max-size (slice-max-size)
           Set the limit of the size of each slice in bytes. If not specified
           but RTP payload size (ps) is specified, that is used.

       stats (stats)
           Set the file name for multi-pass stats.

       nal-hrd (nal-hrd)
           Set signal HRD information (requires vbv-bufsize to be set).
           Possible values:

           none (none)
               Disable HRD information signaling.

           vbr (vbr)
               Variable bit rate.

           cbr (cbr)
               Constant bit rate (not allowed in MP4 container).

       x264opts (N.A.)
           Set any x264 option, see x264 --fullhelp for a list.

           Argument is a list of key=value couples separated by ":". In filter
           and psy-rd options that use ":" as a separator themselves, use ","
           instead. They accept it as well since long ago but this is kept
           undocumented for some reason.

           For example to specify libx264 encoding options with ffmpeg:

                   ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

       a53cc boolean
           Import closed captions (which must be ATSC compatible format) into
           output.  Only the mpeg2 and h264 decoders provide these. Default is
           1 (on).

       x264-params (N.A.)
           Override the x264 configuration using a :-separated list of
           key=value parameters.

           This option is functionally the same as the x264opts, but is
           duplicated for compatibility with the Libav fork.

           For example to specify libx264 encoding options with ffmpeg:

                   ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
                   cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
                   no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT

       Encoding ffpresets for common usages are provided so they can be used
       with the general presets system (e.g. passing the pre option).

   libx265
       x265 H.265/HEVC encoder wrapper.

       This encoder requires the presence of the libx265 headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libx265.

       Options

       b   Sets target video bitrate.

       bf
       g   Set the GOP size.

       keyint_min
           Minimum GOP size.

       refs
           Number of reference frames each P-frame can use. The range is from
           1-16.

       preset
           Set the x265 preset.

       tune
           Set the x265 tune parameter.

       profile
           Set profile restrictions.

       crf Set the quality for constant quality mode.

       qp  Set constant quantization rate control method parameter.

       qmin
           Minimum quantizer scale.

       qmax
           Maximum quantizer scale.

       qdiff
           Maximum difference between quantizer scales.

       qblur
           Quantizer curve blur

       qcomp
           Quantizer curve compression factor

       i_qfactor
       b_qfactor
       forced-idr
           Normally, when forcing a I-frame type, the encoder can select any
           type of I-frame. This option forces it to choose an IDR-frame.

       x265-params
           Set x265 options using a list of key=value couples separated by
           ":". See x265 --help for a list of options.

           For example to specify libx265 encoding options with -x265-params:

                   ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4

   libxavs2
       xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.

       This encoder requires the presence of the libxavs2 headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libxavs2.

       The following standard libavcodec options are used:

       o   b / bit_rate

       o   g / gop_size

       o   bf / max_b_frames

       The encoder also has its own specific options:

       Options

       lcu_row_threads
           Set the number of parallel threads for rows from 1 to 8 (default
           5).

       initial_qp
           Set the xavs2 quantization parameter from 1 to 63 (default 34).
           This is used to set the initial qp for the first frame.

       qp  Set the xavs2 quantization parameter from 1 to 63 (default 34).
           This is used to set the qp value under constant-QP mode.

       max_qp
           Set the max qp for rate control from 1 to 63 (default 55).

       min_qp
           Set the min qp for rate control from 1 to 63 (default 20).

       speed_level
           Set the Speed level from 0 to 9 (default 0). Higher is better but
           slower.

       log_level
           Set the log level from -1 to 3 (default 0). -1: none, 0: error, 1:
           warning, 2: info, 3: debug.

       xavs2-params
           Set xavs2 options using a list of key=value couples separated by
           ":".

           For example to specify libxavs2 encoding options with
           -xavs2-params:

                   ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2

   libxvid
       Xvid MPEG-4 Part 2 encoder wrapper.

       This encoder requires the presence of the libxvidcore headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libxvid --enable-gpl".

       The native "mpeg4" encoder supports the MPEG-4 Part 2 format, so users
       can encode to this format without this library.

       Options

       The following options are supported by the libxvid wrapper. Some of the
       following options are listed but are not documented, and correspond to
       shared codec options. See the Codec Options chapter for their
       documentation. The other shared options which are not listed have no
       effect for the libxvid encoder.

       b
       g
       qmin
       qmax
       mpeg_quant
       threads
       bf
       b_qfactor
       b_qoffset
       flags
           Set specific encoding flags. Possible values:

           mv4 Use four motion vector by macroblock.

           aic Enable high quality AC prediction.

           gray
               Only encode grayscale.

           gmc Enable the use of global motion compensation (GMC).

           qpel
               Enable quarter-pixel motion compensation.

           cgop
               Enable closed GOP.

           global_header
               Place global headers in extradata instead of every keyframe.

       trellis
       me_method
           Set motion estimation method. Possible values in decreasing order
           of speed and increasing order of quality:

           zero
               Use no motion estimation (default).

           phods
           x1
           log Enable advanced diamond zonal search for 16x16 blocks and half-
               pixel refinement for 16x16 blocks. x1 and log are aliases for
               phods.

           epzs
               Enable all of the things described above, plus advanced diamond
               zonal search for 8x8 blocks, half-pixel refinement for 8x8
               blocks, and motion estimation on chroma planes.

           full
               Enable all of the things described above, plus extended 16x16
               and 8x8 blocks search.

       mbd Set macroblock decision algorithm. Possible values in the
           increasing order of quality:

           simple
               Use macroblock comparing function algorithm (default).

           bits
               Enable rate distortion-based half pixel and quarter pixel
               refinement for 16x16 blocks.

           rd  Enable all of the things described above, plus rate distortion-
               based half pixel and quarter pixel refinement for 8x8 blocks,
               and rate distortion-based search using square pattern.

       lumi_aq
           Enable lumi masking adaptive quantization when set to 1. Default is
           0 (disabled).

       variance_aq
           Enable variance adaptive quantization when set to 1. Default is 0
           (disabled).

           When combined with lumi_aq, the resulting quality will not be
           better than any of the two specified individually. In other words,
           the resulting quality will be the worse one of the two effects.

       ssim
           Set structural similarity (SSIM) displaying method. Possible
           values:

           off Disable displaying of SSIM information.

           avg Output average SSIM at the end of encoding to stdout. The
               format of showing the average SSIM is:

                       Average SSIM: %f

               For users who are not familiar with C, %f means a float number,
               or a decimal (e.g. 0.939232).

           frame
               Output both per-frame SSIM data during encoding and average
               SSIM at the end of encoding to stdout. The format of per-frame
               information is:

                              SSIM: avg: %1.3f min: %1.3f max: %1.3f

               For users who are not familiar with C, %1.3f means a float
               number rounded to 3 digits after the dot (e.g. 0.932).

       ssim_acc
           Set SSIM accuracy. Valid options are integers within the range of
           0-4, while 0 gives the most accurate result and 4 computes the
           fastest.

   MediaFoundation
       This provides wrappers to encoders (both audio and video) in the
       MediaFoundation framework. It can access both SW and HW encoders.
       Video encoders can take input in either of nv12 or yuv420p form (some
       encoders support both, some support only either - in practice, nv12 is
       the safer choice, especially among HW encoders).

   mpeg2
       MPEG-2 video encoder.

       Options

       profile
           Select the mpeg2 profile to encode:

           422
           high
           ss  Spatially Scalable

           snr SNR Scalable

           main
           simple
       level
           Select the mpeg2 level to encode:

           high
           high1440
           main
           low
       seq_disp_ext integer
           Specifies if the encoder should write a sequence_display_extension
           to the output.

           -1
           auto
               Decide automatically to write it or not (this is the default)
               by checking if the data to be written is different from the
               default or unspecified values.

           0
           never
               Never write it.

           1
           always
               Always write it.

       video_format integer
           Specifies the video_format written into the sequence display
           extension indicating the source of the video pictures. The default
           is unspecified, can be component, pal, ntsc, secam or mac.  For
           maximum compatibility, use component.

       a53cc boolean
           Import closed captions (which must be ATSC compatible format) into
           output.  Default is 1 (on).

   png
       PNG image encoder.

       Private options

       dpi integer
           Set physical density of pixels, in dots per inch, unset by default

       dpm integer
           Set physical density of pixels, in dots per meter, unset by default

   ProRes
       Apple ProRes encoder.

       FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
       The used encoder can be chosen with the "-vcodec" option.

       Private Options for prores-ks

       profile integer
           Select the ProRes profile to encode

           proxy
           lt
           standard
           hq
           4444
           4444xq
       quant_mat integer
           Select quantization matrix.

           auto
           default
           proxy
           lt
           standard
           hq

           If set to auto, the matrix matching the profile will be picked.  If
           not set, the matrix providing the highest quality, default, will be
           picked.

       bits_per_mb integer
           How many bits to allot for coding one macroblock. Different
           profiles use between 200 and 2400 bits per macroblock, the maximum
           is 8000.

       mbs_per_slice integer
           Number of macroblocks in each slice (1-8); the default value (8)
           should be good in almost all situations.

       vendor string
           Override the 4-byte vendor ID.  A custom vendor ID like apl0 would
           claim the stream was produced by the Apple encoder.

       alpha_bits integer
           Specify number of bits for alpha component.  Possible values are 0,
           8 and 16.  Use 0 to disable alpha plane coding.

       Speed considerations

       In the default mode of operation the encoder has to honor frame
       constraints (i.e. not produce frames with size bigger than requested)
       while still making output picture as good as possible.  A frame
       containing a lot of small details is harder to compress and the encoder
       would spend more time searching for appropriate quantizers for each
       slice.

       Setting a higher bits_per_mb limit will improve the speed.

       For the fastest encoding speed set the qscale parameter (4 is the
       recommended value) and do not set a size constraint.

   QSV encoders
       The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC,
       JPEG/MJPEG and VP9)

       The ratecontrol method is selected as follows:

       o   When global_quality is specified, a quality-based mode is used.
           Specifically this means either

           -   CQP - constant quantizer scale, when the qscale codec flag is
               also set (the -qscale ffmpeg option).

           -   LA_ICQ - intelligent constant quality with lookahead, when the
               look_ahead option is also set.

           -   ICQ -- intelligent constant quality otherwise.

       o   Otherwise, a bitrate-based mode is used. For all of those, you
           should specify at least the desired average bitrate with the b
           option.

           -   LA - VBR with lookahead, when the look_ahead option is
               specified.

           -   VCM - video conferencing mode, when the vcm option is set.

           -   CBR - constant bitrate, when maxrate is specified and equal to
               the average bitrate.

           -   VBR - variable bitrate, when maxrate is specified, but is
               higher than the average bitrate.

           -   AVBR - average VBR mode, when maxrate is not specified. This
               mode is further configured by the avbr_accuracy and
               avbr_convergence options.

       Note that depending on your system, a different mode than the one you
       specified may be selected by the encoder. Set the verbosity level to
       verbose or higher to see the actual settings used by the QSV runtime.

       Additional libavcodec global options are mapped to MSDK options as
       follows:

       o   g/gop_size -> GopPicSize

       o   bf/max_b_frames+1 -> GopRefDist

       o   rc_init_occupancy/rc_initial_buffer_occupancy -> InitialDelayInKB

       o   slices -> NumSlice

       o   refs -> NumRefFrame

       o   b_strategy/b_frame_strategy -> BRefType

       o   cgop/CLOSED_GOP codec flag -> GopOptFlag

       o   For the CQP mode, the i_qfactor/i_qoffset and b_qfactor/b_qoffset
           set the difference between QPP and QPI, and QPP and QPB
           respectively.

       o   Setting the coder option to the value vlc will make the H.264
           encoder use CAVLC instead of CABAC.

   snow
       Options

       iterative_dia_size
           dia size for the iterative motion estimation

   VAAPI encoders
       Wrappers for hardware encoders accessible via VAAPI.

       These encoders only accept input in VAAPI hardware surfaces.  If you
       have input in software frames, use the hwupload filter to upload them
       to the GPU.

       The following standard libavcodec options are used:

       o   g / gop_size

       o   bf / max_b_frames

       o   profile

           If not set, this will be determined automatically from the format
           of the input frames and the profiles supported by the driver.

       o   level

       o   b / bit_rate

       o   maxrate / rc_max_rate

       o   bufsize / rc_buffer_size

       o   rc_init_occupancy / rc_initial_buffer_occupancy

       o   compression_level

           Speed / quality tradeoff: higher values are faster / worse quality.

       o   q / global_quality

           Size / quality tradeoff: higher values are smaller / worse quality.

       o   qmin

       o   qmax

       o   i_qfactor / i_quant_factor

       o   i_qoffset / i_quant_offset

       o   b_qfactor / b_quant_factor

       o   b_qoffset / b_quant_offset

       o   slices

       All encoders support the following options:

       low_power
           Some drivers/platforms offer a second encoder for some codecs
           intended to use less power than the default encoder; setting this
           option will attempt to use that encoder.  Note that it may support
           a reduced feature set, so some other options may not be available
           in this mode.

       idr_interval
           Set the number of normal intra frames between full-refresh (IDR)
           frames in open-GOP mode.  The intra frames are still IRAPs, but
           will not include global headers and may have non-decodable leading
           pictures.

       b_depth
           Set the B-frame reference depth.  When set to one (the default),
           all B-frames will refer only to P- or I-frames.  When set to
           greater values multiple layers of B-frames will be present, frames
           in each layer only referring to frames in higher layers.

       rc_mode
           Set the rate control mode to use.  A given driver may only support
           a subset of modes.

           Possible modes:

           auto
               Choose the mode automatically based on driver support and the
               other options.  This is the default.

           CQP Constant-quality.

           CBR Constant-bitrate.

           VBR Variable-bitrate.

           ICQ Intelligent constant-quality.

           QVBR
               Quality-defined variable-bitrate.

           AVBR
               Average variable bitrate.

       Each encoder also has its own specific options:

       h264_vaapi
           profile sets the value of profile_idc and the
           constraint_set*_flags.  level sets the value of level_idc.

           coder
               Set entropy encoder (default is cabac).  Possible values:

               ac
               cabac
                   Use CABAC.

               vlc
               cavlc
                   Use CAVLC.

           aud Include access unit delimiters in the stream (not included by
               default).

           sei Set SEI message types to include.  Some combination of the
               following values:

               identifier
                   Include a user_data_unregistered message containing
                   information about the encoder.

               timing
                   Include picture timing parameters (buffering_period and
                   pic_timing messages).

               recovery_point
                   Include recovery points where appropriate (recovery_point
                   messages).

       hevc_vaapi
           profile and level set the values of general_profile_idc and
           general_level_idc respectively.

           aud Include access unit delimiters in the stream (not included by
               default).

           tier
               Set general_tier_flag.  This may affect the level chosen for
               the stream if it is not explicitly specified.

           sei Set SEI message types to include.  Some combination of the
               following values:

               hdr Include HDR metadata if the input frames have it
                   (mastering_display_colour_volume and content_light_level
                   messages).

           tiles
               Set the number of tiles to encode the input video with, as
               columns x rows.  Larger numbers allow greater parallelism in
               both encoding and decoding, but may decrease coding efficiency.

       mjpeg_vaapi
           Only baseline DCT encoding is supported.  The encoder always uses
           the standard quantisation and huffman tables - global_quality
           scales the standard quantisation table (range 1-100).

           For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported.
           RGB is also supported, and will create an RGB JPEG.

           jfif
               Include JFIF header in each frame (not included by default).

           huffman
               Include standard huffman tables (on by default).  Turning this
               off will save a few hundred bytes in each output frame, but may
               lose compatibility with some JPEG decoders which don't fully
               handle MJPEG.

       mpeg2_vaapi
           profile and level set the value of profile_and_level_indication.

       vp8_vaapi
           B-frames are not supported.

           global_quality sets the q_idx used for non-key frames (range
           0-127).

           loop_filter_level
           loop_filter_sharpness
               Manually set the loop filter parameters.

       vp9_vaapi
           global_quality sets the q_idx used for P-frames (range 0-255).

           loop_filter_level
           loop_filter_sharpness
               Manually set the loop filter parameters.

           B-frames are supported, but the output stream is always in encode
           order rather than display order.  If B-frames are enabled, it may
           be necessary to use the vp9_raw_reorder bitstream filter to modify
           the output stream to display frames in the correct order.

           Only normal frames are produced - the vp9_superframe bitstream
           filter may be required to produce a stream usable with all
           decoders.

   vc2
       SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed
       at professional broadcasting but since it supports yuv420, yuv422 and
       yuv444 at 8 (limited range or full range), 10 or 12 bits, this makes it
       suitable for other tasks which require low overhead and low compression
       (like screen recording).

       Options

       b   Sets target video bitrate. Usually that's around 1:6 of the
           uncompressed video bitrate (e.g. for 1920x1080 50fps yuv422p10
           that's around 400Mbps). Higher values (close to the uncompressed
           bitrate) turn on lossless compression mode.

       field_order
           Enables field coding when set (e.g. to tt - top field first) for
           interlaced inputs. Should increase compression with interlaced
           content as it splits the fields and encodes each separately.

       wavelet_depth
           Sets the total amount of wavelet transforms to apply, between 1 and
           5 (default).  Lower values reduce compression and quality. Less
           capable decoders may not be able to handle values of wavelet_depth
           over 3.

       wavelet_type
           Sets the transform type. Currently only 5_3 (LeGall) and 9_7
           (Deslauriers-Dubuc) are implemented, with 9_7 being the one with
           better compression and thus is the default.

       slice_width
       slice_height
           Sets the slice size for each slice. Larger values result in better
           compression.  For compatibility with other more limited decoders
           use slice_width of 32 and slice_height of 8.

       tolerance
           Sets the undershoot tolerance of the rate control system in
           percent. This is to prevent an expensive search from being run.

       qm  Sets the quantization matrix preset to use by default or when
           wavelet_depth is set to 5

           -   default Uses the default quantization matrix from the
               specifications, extended with values for the fifth level. This
               provides a good balance between keeping detail and omitting
               artifacts.

           -   flat Use a completely zeroed out quantization matrix. This
               increases PSNR but might reduce perception. Use in bogus
               benchmarks.

           -   color Reduces detail but attempts to preserve color at
               extremely low bitrates.


SUBTITLES ENCODERS

   dvdsub
       This codec encodes the bitmap subtitle format that is used in DVDs.
       Typically they are stored in VOBSUB file pairs (*.idx + *.sub), and
       they can also be used in Matroska files.

       Options

       palette
           Specify the global palette used by the bitmaps.

           The format for this option is a string containing 16 24-bits
           hexadecimal numbers (without 0x prefix) separated by commas, for
           example "0d00ee, ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b,
           0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c,
           7c127b".

       even_rows_fix
           When set to 1, enable a work-around that makes the number of pixel
           rows even in all subtitles.  This fixes a problem with some players
           that cut off the bottom row if the number is odd.  The work-around
           just adds a fully transparent row if needed.  The overhead is low,
           typically one byte per subtitle on average.

           By default, this work-around is disabled.


SEE ALSO

       ffmpeg(1), ffplay(1), ffprobe(1), libavcodec(3)


AUTHORS

       The FFmpeg developers.

       For details about the authorship, see the Git history of the project
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
       the FFmpeg source directory, or browsing the online repository at
       <http://source.ffmpeg.org>.

       Maintainers for the specific components are listed in the file
       MAINTAINERS in the source code tree.



                                                              ffmpeg-codecs(1)

ffmpeg 4.4 - Generated Fri Apr 23 14:49:27 CDT 2021
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