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GstVideoScaler

GstVideoScaler — Utility object for rescaling video frames

Types and Values

Includes

#include <gst/video/video-scaler.h>

Description

GstVideoScaler is a utility object for rescaling and resampling video frames using various interpolation / sampling methods.

Functions

gst_video_scaler_2d ()

void
gst_video_scaler_2d (GstVideoScaler *hscale,
                     GstVideoScaler *vscale,
                     GstVideoFormat format,
                     gpointer src,
                     gint src_stride,
                     gpointer dest,
                     gint dest_stride,
                     guint x,
                     guint y,
                     guint width,
                     guint height);

Scale a rectangle of pixels in src with src_stride to dest with dest_stride using the horizontal scaler hscaler and the vertical scaler vscale .

One or both of hscale and vscale can be NULL to only perform scaling in one dimension or do a copy without scaling.

x and y are the coordinates in the destination image to process.

Parameters

hscale

a horzontal GstVideoScaler

 

vscale

a vertical GstVideoScaler

 

format

a GstVideoFormat for srcs and dest

 

src

source pixels

 

src_stride

source pixels stride

 

dest

destination pixels

 

dest_stride

destination pixels stride

 

x

the horizontal destination offset

 

y

the vertical destination offset

 

width

the number of output pixels to scale

 

height

the number of output lines to scale

 

gst_video_scaler_combine_packed_YUV ()

GstVideoScaler *
gst_video_scaler_combine_packed_YUV (GstVideoScaler *y_scale,
                                     GstVideoScaler *uv_scale,
                                     GstVideoFormat in_format,
                                     GstVideoFormat out_format);

Combine a scaler for Y and UV into one scaler for the packed format .

[skip]

Parameters

y_scale

a scaler for the Y component

 

uv_scale

a scaler for the U and V components

 

in_format

the input video format

 

out_format

the output video format

 

Returns

a new horizontal videoscaler for format .

Since: 1.6


gst_video_scaler_free ()

void
gst_video_scaler_free (GstVideoScaler *scale);

Free a previously allocated GstVideoScaler scale .

Parameters

scale

a GstVideoScaler

 

gst_video_scaler_get_coeff ()

const gdouble *
gst_video_scaler_get_coeff (GstVideoScaler *scale,
                            guint out_offset,
                            guint *in_offset,
                            guint *n_taps);

For a given pixel at out_offset , get the first required input pixel at in_offset and the n_taps filter coefficients.

Note that for interlaced content, in_offset needs to be incremented with 2 to get the next input line.

Parameters

scale

a GstVideoScaler

 

out_offset

an output offset

 

in_offset

result input offset

 

n_taps

result n_taps

 

Returns

an array of n_tap gdouble values with filter coefficients.


gst_video_scaler_horizontal ()

void
gst_video_scaler_horizontal (GstVideoScaler *scale,
                             GstVideoFormat format,
                             gpointer src,
                             gpointer dest,
                             guint dest_offset,
                             guint width);

Horizontally scale the pixels in src to dest , starting from dest_offset for width samples.

Parameters

scale

a GstVideoScaler

 

format

a GstVideoFormat for src and dest

 

src

source pixels

 

dest

destination pixels

 

dest_offset

the horizontal destination offset

 

width

the number of pixels to scale

 

gst_video_scaler_new ()

GstVideoScaler *
gst_video_scaler_new (GstVideoResamplerMethod method,
                      GstVideoScalerFlags flags,
                      guint n_taps,
                      guint in_size,
                      guint out_size,
                      GstStructure *options);

Make a new method video scaler. in_size source lines/pixels will be scaled to out_size destination lines/pixels.

n_taps specifies the amount of pixels to use from the source for one output pixel. If n_taps is 0, this function chooses a good value automatically based on the method and in_size /out_size .

[skip]

Parameters

method

a GstVideoResamplerMethod

 

flags

GstVideoScalerFlags

 

n_taps

number of taps to use

 

in_size

number of source elements

 

out_size

number of destination elements

 

options

extra options.

[allow-none]

Returns

a GstVideoResample


gst_video_scaler_vertical ()

void
gst_video_scaler_vertical (GstVideoScaler *scale,
                           GstVideoFormat format,
                           gpointer src_lines[],
                           gpointer dest,
                           guint dest_offset,
                           guint width);

Vertically combine width pixels in the lines in src_lines to dest . dest is the location of the target line at dest_offset and srcs are the input lines for dest_offset , as obtained with gst_video_scaler_get_info().

Parameters

scale

a GstVideoScaler

 

format

a GstVideoFormat for srcs and dest

 

src_lines

source pixels lines

 

dest

destination pixels

 

dest_offset

the vertical destination offset

 

width

the number of pixels to scale

 

gst_video_scaler_get_max_taps ()

guint
gst_video_scaler_get_max_taps (GstVideoScaler *scale);

Get the maximum number of taps for scale .

Parameters

scale

a GstVideoScaler

 

Returns

the maximum number of taps

Types and Values

GstVideoScaler

typedef struct _GstVideoScaler GstVideoScaler;

enum GstVideoScalerFlags

Different scale flags.

Members

GST_VIDEO_SCALER_FLAG_NONE

no flags

 

GST_VIDEO_SCALER_FLAG_INTERLACED

Set up a scaler for interlaced content

 
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