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| guint64 | alignment-threshold | Read / Write |
| gint64 | buffer-time | Read / Write |
| gboolean | can-activate-pull | Read / Write |
| guint64 | discont-wait | Read / Write |
| gint64 | drift-tolerance | Read / Write |
| gint64 | latency-time | Read / Write |
| gboolean | provide-clock | Read / Write |
| GstAudioBaseSinkSlaveMethod | slave-method | Read / Write |
| struct | GstAudioBaseSink |
| struct | GstAudioBaseSinkClass |
| enum | GstAudioBaseSinkSlaveMethod |
| enum | GstAudioBaseSinkDiscontReason |
GObject ╰── GInitiallyUnowned ╰── GstObject ╰── GstElement ╰── GstBaseSink ╰── GstAudioBaseSink ╰── GstAudioSink
This is the base class for audio sinks. Subclasses need to implement the ::create_ringbuffer vmethod. This base class will then take care of writing samples to the ringbuffer, synchronisation, clipping and flushing.
void (*GstAudioBaseSinkCustomSlavingCallback) (GstAudioBaseSink *sink,GstClockTime etime,GstClockTime itime,GstClockTimeDiff *requested_skew,GstAudioBaseSinkDiscontReason discont_reason,gpointer user_data);
This function is set with gst_audio_base_sink_set_custom_slaving_callback()
and is called during playback. It receives the current time of external and
internal clocks, which the callback can then use to apply any custom
slaving/synchronization schemes.
The external clock is the sink's element clock, the internal one is the internal audio clock. The internal audio clock's calibration is applied to the timestamps before they are passed to the callback. The difference between etime and itime is the skew; how much internal and external clock lie apart from each other. A skew of 0 means both clocks are perfectly in sync. itime > etime means the external clock is going slower, while itime < etime means it is going faster than the internal clock. etime and itime are always valid timestamps, except for when a discontinuity happens.
requested_skew is an output value the callback can write to. It informs the sink of whether or not it should move the playout pointer, and if so, by how much. This pointer is only NULL if a discontinuity occurs; otherwise, it is safe to write to *requested_skew. The default skew is 0.
The sink may experience discontinuities. If one happens, discont is TRUE, itime, etime are set to GST_CLOCK_TIME_NONE, and requested_skew is NULL. This makes it possible to reset custom clock slaving algorithms when a discontinuity happens.
sink |
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etime |
external clock time |
|
itime |
internal clock time |
|
requested_skew |
skew amount requested by the callback |
|
discont_reason |
reason for discontinuity (if any) |
|
user_data |
user data |
Since: 1.6
#define GST_AUDIO_BASE_SINK_CLOCK(obj) (GST_AUDIO_BASE_SINK (obj)->clock)
Get the GstClock of obj
.
#define GST_AUDIO_BASE_SINK_PAD(obj) (GST_BASE_SINK (obj)->sinkpad)
Get the sink GstPad of obj
.
GstAudioRingBuffer *
gst_audio_base_sink_create_ringbuffer (GstAudioBaseSink *sink);
Create and return the GstAudioRingBuffer for sink
. This function will
call the ::create_ringbuffer vmethod and will set sink
as the parent of
the returned buffer (see gst_object_set_parent()).
void gst_audio_base_sink_set_provide_clock (GstAudioBaseSink *sink,gboolean provide);
Controls whether sink
will provide a clock or not. If provide
is TRUE,
gst_element_provide_clock() will return a clock that reflects the datarate
of sink
. If provide
is FALSE, gst_element_provide_clock() will return
NULL.
gboolean
gst_audio_base_sink_get_provide_clock (GstAudioBaseSink *sink);
Queries whether sink
will provide a clock or not. See also
gst_audio_base_sink_set_provide_clock.
void gst_audio_base_sink_set_slave_method (GstAudioBaseSink *sink,GstAudioBaseSinkSlaveMethod method);
Controls how clock slaving will be performed in sink
.
GstAudioBaseSinkSlaveMethod
gst_audio_base_sink_get_slave_method (GstAudioBaseSink *sink);
Get the current slave method used by sink
.
void gst_audio_base_sink_set_drift_tolerance (GstAudioBaseSink *sink,gint64 drift_tolerance);
Controls the sink's drift tolerance.
gint64
gst_audio_base_sink_get_drift_tolerance
(GstAudioBaseSink *sink);
Get the current drift tolerance, in microseconds, used by sink
.
void gst_audio_base_sink_set_alignment_threshold (GstAudioBaseSink *sink,GstClockTime alignment_threshold);
Controls the sink's alignment threshold.
GstClockTime
gst_audio_base_sink_get_alignment_threshold
(GstAudioBaseSink *sink);
Get the current alignment threshold, in nanoseconds, used by sink
.
void gst_audio_base_sink_set_discont_wait (GstAudioBaseSink *sink,GstClockTime discont_wait);
Controls how long the sink will wait before creating a discontinuity.
GstClockTime
gst_audio_base_sink_get_discont_wait (GstAudioBaseSink *sink);
Get the current discont wait, in nanoseconds, used by sink
.
void gst_audio_base_sink_set_custom_slaving_callback (GstAudioBaseSink *sink,GstAudioBaseSinkCustomSlavingCallback callback,gpointer user_data,GDestroyNotify notify);
Sets the custom slaving callback. This callback will be invoked if the slave-method property is set to GST_AUDIO_BASE_SINK_SLAVE_CUSTOM and the audio sink receives and plays samples.
Setting the callback to NULL causes the sink to behave as if the GST_AUDIO_BASE_SINK_SLAVE_NONE method were used.
sink |
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callback |
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user_data |
user data passed to the callback |
|
notify |
called when user_data becomes unused |
Since: 1.6
void
gst_audio_base_sink_report_device_failure
(GstAudioBaseSink *sink);
Informs this base class that the audio output device has failed for some reason, causing a discontinuity (for example, because the device recovered from the error, but lost all contents of its ring buffer). This function is typically called by derived classes, and is useful for the custom slave method.
Since: 1.6
struct GstAudioBaseSinkClass {
GstBaseSinkClass parent_class;
/* subclass ringbuffer allocation */
GstAudioRingBuffer* (*create_ringbuffer) (GstAudioBaseSink *sink);
/* subclass payloader */
GstBuffer* (*payload) (GstAudioBaseSink *sink,
GstBuffer *buffer);
};
GstAudioBaseSink class. Override the vmethod to implement functionality.
create and return a GstAudioRingBuffer to write to. |
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payload data in a format suitable to write to the sink. If no payloading is required, returns a reffed copy of the original buffer, else returns the payloaded buffer with all other metadata copied. |
Different possible clock slaving algorithms used when the internal audio clock is not selected as the pipeline master clock.
Different possible reasons for discontinuities. This enum is useful for the custom slave method.
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No discontinuity occurred |
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New caps are set, causing renegotiotion |
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Samples have been flushed |
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Sink was synchronized to the estimated latency (occurs during initialization) |
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Aligning buffers failed because the timestamps are too discontinuous |
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Audio output device experienced and recovered from an error but introduced latency in the process (see also |
Since: 1.6
“alignment-threshold” property“alignment-threshold” guint64
Timestamp alignment threshold in nanoseconds.
Flags: Read / Write
Allowed values: [1,18446744073709551614]
Default value: 40000000
“buffer-time” property“buffer-time” gint64
Size of audio buffer in microseconds, this is the minimum latency that the sink reports.
Flags: Read / Write
Allowed values: >= 1
Default value: 200000
“can-activate-pull” property“can-activate-pull” gboolean
Allow pull-based scheduling.
Flags: Read / Write
Default value: FALSE
“discont-wait” property“discont-wait” guint64
A window of time in nanoseconds to wait before creating a discontinuity as a result of breaching the drift-tolerance.
Flags: Read / Write
Allowed values: <= 18446744073709551614
Default value: 1000000000
“drift-tolerance” property“drift-tolerance” gint64
Controls the amount of time in microseconds that clocks are allowed to drift before resynchronisation happens.
Flags: Read / Write
Allowed values: >= 1
Default value: 40000
“latency-time” property“latency-time” gint64
The minimum amount of data to write in each iteration in microseconds.
Flags: Read / Write
Allowed values: >= 1
Default value: 10000
“provide-clock” property“provide-clock” gboolean
Provide a clock to be used as the global pipeline clock.
Flags: Read / Write
Default value: TRUE
“slave-method” property“slave-method” GstAudioBaseSinkSlaveMethod
Algorithm used to match the rate of the masterclock.
Flags: Read / Write
Default value: GST_AUDIO_BASE_SINK_SLAVE_SKEW