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GstAudioSink — Simple base class for audio sinks

Types and Values

Object Hierarchy

    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstBaseSink
                    ╰── GstAudioBaseSink
                        ╰── GstAudioSink


#include <gst/audio/gstaudiosink.h>


This is the most simple base class for audio sinks that only requires subclasses to implement a set of simple functions:

  • open() :Open the device.

  • prepare() :Configure the device with the specified format.

  • write() :Write samples to the device.

  • reset() :Unblock writes and flush the device.

  • delay() :Get the number of samples written but not yet played by the device.

  • unprepare() :Undo operations done by prepare.

  • close() :Close the device.

All scheduling of samples and timestamps is done in this base class together with GstAudioBaseSink using a default implementation of a GstAudioRingBuffer that uses threads.


Types and Values

struct GstAudioSink

struct GstAudioSink;

Opaque GstAudioSink.

struct GstAudioSinkClass

struct GstAudioSinkClass {
  GstAudioBaseSinkClass parent_class;

  /* vtable */

  /* open the device with given specs */
  gboolean (*open)      (GstAudioSink *sink);
  /* prepare resources and state to operate with the given specs */
  gboolean (*prepare)   (GstAudioSink *sink, GstAudioRingBufferSpec *spec);
  /* undo anything that was done in prepare() */
  gboolean (*unprepare) (GstAudioSink *sink);
  /* close the device */
  gboolean (*close)     (GstAudioSink *sink);
  /* write samples to the device */
  gint     (*write)     (GstAudioSink *sink, gpointer data, guint length);
  /* get number of frames queued in the device */
  guint    (*delay)     (GstAudioSink *sink);
  /* reset the audio device, unblock from a write */
  void     (*reset)     (GstAudioSink *sink);

GstAudioSink class. Override the vmethods to implement functionality.


open ()

Open the device. No configuration needs to be done at this point. This function is also used to check if the device is available.


prepare ()

Prepare the device to operate with the specified parameters.


unprepare ()

Undo operations done in prepare.


close ()

Close the device.


write ()

Write data to the device.


delay ()

Return how many frames are still in the device. This is used to drive the synchronisation.


reset ()

Returns as quickly as possible from a write and flush any pending samples from the device.

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