GstVideoDecoder

GstVideoDecoder — Base class for video decoders

Functions

#define GST_VIDEO_DECODER_ERROR()
#define GST_VIDEO_DECODER_SINK_PAD()
#define GST_VIDEO_DECODER_SRC_PAD()
#define GST_VIDEO_DECODER_STREAM_LOCK()
#define GST_VIDEO_DECODER_STREAM_UNLOCK()
#define GST_VIDEO_DECODER_INPUT_SEGMENT()
#define GST_VIDEO_DECODER_OUTPUT_SEGMENT()
void gst_video_decoder_add_to_frame ()
GstBuffer * gst_video_decoder_allocate_output_buffer ()
GstFlowReturn gst_video_decoder_allocate_output_frame ()
void gst_video_decoder_get_allocator ()
GstBufferPool * gst_video_decoder_get_buffer_pool ()
GstFlowReturn gst_video_decoder_drop_frame ()
GstFlowReturn gst_video_decoder_finish_frame ()
void gst_video_decoder_release_frame ()
gboolean gst_video_decoder_negotiate ()
GstVideoCodecFrame * gst_video_decoder_get_frame ()
GList * gst_video_decoder_get_frames ()
GstClockTimeDiff gst_video_decoder_get_max_decode_time ()
gint gst_video_decoder_get_max_errors ()
GstVideoCodecFrame * gst_video_decoder_get_oldest_frame ()
gboolean gst_video_decoder_get_packetized ()
gsize gst_video_decoder_get_pending_frame_size ()
gdouble gst_video_decoder_get_qos_proportion ()
GstFlowReturn gst_video_decoder_have_frame ()
void gst_video_decoder_get_latency ()
void gst_video_decoder_set_latency ()
gint gst_video_decoder_get_estimate_rate ()
GstVideoCodecState * gst_video_decoder_get_output_state ()
void gst_video_decoder_set_estimate_rate ()
GstVideoCodecState * gst_video_decoder_set_output_state ()
void gst_video_decoder_set_max_errors ()
void gst_video_decoder_set_packetized ()
gboolean gst_video_decoder_get_needs_format ()
void gst_video_decoder_set_needs_format ()
void gst_video_decoder_merge_tags ()

Types and Values

Object Hierarchy


Description

This base class is for video decoders turning encoded data into raw video frames.

The GstVideoDecoder base class and derived subclasses should cooperate as follows:

  1. Configuration

    • Initially, GstVideoDecoder calls start when the decoder element is activated, which allows the subclass to perform any global setup.

    • GstVideoDecoder calls set_format to inform the subclass of caps describing input video data that it is about to receive, including possibly configuration data. While unlikely, it might be called more than once, if changing input parameters require reconfiguration.

    • Incoming data buffers are processed as needed, described in Data Processing below.

    • GstVideoDecoder calls stop at end of all processing.

  2. Data processing

    • The base class gathers input data, and optionally allows subclass to parse this into subsequently manageable chunks, typically corresponding to and referred to as 'frames'.

    • Each input frame is provided in turn to the subclass' handle_frame callback. The ownership of the frame is given to the handle_frame callback.

    • If codec processing results in decoded data, the subclass should call gst_video_decoder_finish_frame to have decoded data pushed. downstream. Otherwise, the subclass must call gst_video_decoder_drop_frame, to allow the base class to do timestamp and offset tracking, and possibly to requeue the frame for a later attempt in the case of reverse playback.

  3. Shutdown phase

    • The GstVideoDecoder class calls stop to inform the subclass that data parsing will be stopped.

  4. Additional Notes

    • Seeking/Flushing

      • When the pipeline is seeked or otherwise flushed, the subclass is informed via a call to its reset callback, with the hard parameter set to true. This indicates the subclass should drop any internal data queues and timestamps and prepare for a fresh set of buffers to arrive for parsing and decoding.

    • End Of Stream

      • At end-of-stream, the subclass parse function may be called some final times with the at_eos parameter set to true, indicating that the element should not expect any more data to be arriving, and it should parse and remaining frames and call gst_video_decoder_have_frame() if possible.

The subclass is responsible for providing pad template caps for source and sink pads. The pads need to be named "sink" and "src". It also needs to provide information about the ouptput caps, when they are known. This may be when the base class calls the subclass' set_format function, though it might be during decoding, before calling gst_video_decoder_finish_frame . This is done via gst_video_decoder_set_output_state

The subclass is also responsible for providing (presentation) timestamps (likely based on corresponding input ones). If that is not applicable or possible, the base class provides limited framerate based interpolation.

Similarly, the base class provides some limited (legacy) seeking support if specifically requested by the subclass, as full-fledged support should rather be left to upstream demuxer, parser or alike. This simple approach caters for seeking and duration reporting using estimated input bitrates. To enable it, a subclass should call gst_video_decoder_set_estimate_rate to enable handling of incoming byte-streams.

The base class provides some support for reverse playback, in particular in case incoming data is not packetized or upstream does not provide fragments on keyframe boundaries. However, the subclass should then be prepared for the parsing and frame processing stage to occur separately (in normal forward processing, the latter immediately follows the former), The subclass also needs to ensure the parsing stage properly marks keyframes, unless it knows the upstream elements will do so properly for incoming data.

The bare minimum that a functional subclass needs to implement is:

  • Provide pad templates

  • Inform the base class of output caps via gst_video_decoder_set_output_state

  • Parse input data, if it is not considered packetized from upstream Data will be provided to parse which should invoke gst_video_decoder_add_to_frame and gst_video_decoder_have_frame to separate the data belonging to each video frame.

  • Accept data in handle_frame and provide decoded results to gst_video_decoder_finish_frame, or call gst_video_decoder_drop_frame.

Functions

GST_VIDEO_DECODER_ERROR()

#define             GST_VIDEO_DECODER_ERROR(el, w, domain, code, text, debug, ret)

Utility function that video decoder elements can use in case they encountered a data processing error that may be fatal for the current "data unit" but need not prevent subsequent decoding. Such errors are counted and if there are too many, as configured in the context's max_errors, the pipeline will post an error message and the application will be requested to stop further media processing. Otherwise, it is considered a "glitch" and only a warning is logged. In either case, ret is set to the proper value to return to upstream/caller (indicating either GST_FLOW_ERROR or GST_FLOW_OK).

Parameters

el

the base video decoder element that generates the error

 

w

element defined weight of the error, added to error count

 

domain

like CORE, LIBRARY, RESOURCE or STREAM (see gstreamer-GstGError)

 

code

error code defined for that domain (see gstreamer-GstGError)

 

text

the message to display (format string and args enclosed in parentheses)

 

debug

debugging information for the message (format string and args enclosed in parentheses)

 

ret

variable to receive return value

 

GST_VIDEO_DECODER_SINK_PAD()

#define GST_VIDEO_DECODER_SINK_PAD(obj)        (((GstVideoDecoder *) (obj))->sinkpad)

Gives the pointer to the sink GstPad object of the element.

Parameters

obj

a GstVideoDecoder

 

GST_VIDEO_DECODER_SRC_PAD()

#define GST_VIDEO_DECODER_SRC_PAD(obj)         (((GstVideoDecoder *) (obj))->srcpad)

Gives the pointer to the source GstPad object of the element.

Parameters

obj

a GstVideoDecoder

 

GST_VIDEO_DECODER_STREAM_LOCK()

#define GST_VIDEO_DECODER_STREAM_LOCK(decoder) g_rec_mutex_lock (&GST_VIDEO_DECODER (decoder)->stream_lock)

Obtain a lock to protect the decoder function from concurrent access.

Parameters

decoder

video decoder instance

 

GST_VIDEO_DECODER_STREAM_UNLOCK()

#define GST_VIDEO_DECODER_STREAM_UNLOCK(decoder) g_rec_mutex_unlock (&GST_VIDEO_DECODER (decoder)->stream_lock)

Release the lock that protects the decoder function from concurrent access.

Parameters

decoder

video decoder instance

 

GST_VIDEO_DECODER_INPUT_SEGMENT()

#define GST_VIDEO_DECODER_INPUT_SEGMENT(obj)     (GST_VIDEO_DECODER_CAST (obj)->input_segment)

Gives the segment of the element.

Parameters

obj

base decoder instance

 

GST_VIDEO_DECODER_OUTPUT_SEGMENT()

#define GST_VIDEO_DECODER_OUTPUT_SEGMENT(obj)     (GST_VIDEO_DECODER_CAST (obj)->output_segment)

Gives the segment of the element.

Parameters

obj

base decoder instance

 

gst_video_decoder_add_to_frame ()

void
gst_video_decoder_add_to_frame (GstVideoDecoder *decoder,
                                int n_bytes);

Removes next n_bytes of input data and adds it to currently parsed frame.

Parameters

decoder

a GstVideoDecoder

 

n_bytes

the number of bytes to add

 

gst_video_decoder_allocate_output_buffer ()

GstBuffer *
gst_video_decoder_allocate_output_buffer
                               (GstVideoDecoder *decoder);

Helper function that allocates a buffer to hold a video frame for decoder 's current GstVideoCodecState.

You should use gst_video_decoder_allocate_output_frame() instead of this function, if possible at all.

Parameters

decoder

a GstVideoDecoder

 

Returns

allocated buffer, or NULL if no buffer could be allocated (e.g. when downstream is flushing or shutting down).

[transfer full]


gst_video_decoder_allocate_output_frame ()

GstFlowReturn
gst_video_decoder_allocate_output_frame
                               (GstVideoDecoder *decoder,
                                GstVideoCodecFrame *frame);

Helper function that allocates a buffer to hold a video frame for decoder 's current GstVideoCodecState. Subclass should already have configured video state and set src pad caps.

The buffer allocated here is owned by the frame and you should only keep references to the frame, not the buffer.

Parameters

decoder

a GstVideoDecoder

 

frame

a GstVideoCodecFrame

 

Returns

GST_FLOW_OK if an output buffer could be allocated


gst_video_decoder_get_allocator ()

void
gst_video_decoder_get_allocator (GstVideoDecoder *decoder,
                                 GstAllocator **allocator,
                                 GstAllocationParams *params);

Lets GstVideoDecoder sub-classes to know the memory allocator used by the base class and its params .

Unref the allocator after use it.

Parameters

decoder

a GstVideoDecoder

 

allocator

the GstAllocator used.

[out][allow-none][transfer full]

params

the GstAllocatorParams of allocator .

[out][allow-none][transfer full]

gst_video_decoder_get_buffer_pool ()

GstBufferPool *
gst_video_decoder_get_buffer_pool (GstVideoDecoder *decoder);

Parameters

decoder

a GstVideoDecoder

 

Returns

the instance of the GstBufferPool used by the decoder; free it after use it.

[transfer full]


gst_video_decoder_drop_frame ()

GstFlowReturn
gst_video_decoder_drop_frame (GstVideoDecoder *dec,
                              GstVideoCodecFrame *frame);

Similar to gst_video_decoder_finish_frame(), but drops frame in any case and posts a QoS message with the frame's details on the bus. In any case, the frame is considered finished and released.

Parameters

dec

a GstVideoDecoder

 

frame

the GstVideoCodecFrame to drop.

[transfer full]

Returns

a GstFlowReturn, usually GST_FLOW_OK.


gst_video_decoder_finish_frame ()

GstFlowReturn
gst_video_decoder_finish_frame (GstVideoDecoder *decoder,
                                GstVideoCodecFrame *frame);

frame should have a valid decoded data buffer, whose metadata fields are then appropriately set according to frame data and pushed downstream. If no output data is provided, frame is considered skipped. In any case, the frame is considered finished and released.

After calling this function the output buffer of the frame is to be considered read-only. This function will also change the metadata of the buffer.

Parameters

decoder

a GstVideoDecoder

 

frame

a decoded GstVideoCodecFrame.

[transfer full]

Returns

a GstFlowReturn resulting from sending data downstream


gst_video_decoder_release_frame ()

void
gst_video_decoder_release_frame (GstVideoDecoder *dec,
                                 GstVideoCodecFrame *frame);

Similar to gst_video_decoder_drop_frame(), but simply releases frame without any processing other than removing it from list of pending frames, after which it is considered finished and released.

Parameters

dec

a GstVideoDecoder

 

frame

the GstVideoCodecFrame to release.

[transfer full]

Since 1.2.2


gst_video_decoder_negotiate ()

gboolean
gst_video_decoder_negotiate (GstVideoDecoder *decoder);

Negotiate with downstream elements to currently configured GstVideoCodecState. Unmark GST_PAD_FLAG_NEED_RECONFIGURE in any case. But mark it again if negotiate fails.

Parameters

decoder

a GstVideoDecoder

 

Returns

TRUE if the negotiation succeeded, else FALSE.


gst_video_decoder_get_frame ()

GstVideoCodecFrame *
gst_video_decoder_get_frame (GstVideoDecoder *decoder,
                             int frame_number);

Get a pending unfinished GstVideoCodecFrame

Parameters

decoder

a GstVideoDecoder

 

frame_number

system_frame_number of a frame

 

Returns

pending unfinished GstVideoCodecFrame identified by frame_number .

[transfer full]


gst_video_decoder_get_frames ()

GList *
gst_video_decoder_get_frames (GstVideoDecoder *decoder);

Get all pending unfinished GstVideoCodecFrame

Parameters

decoder

a GstVideoDecoder

 

Returns

pending unfinished GstVideoCodecFrame.

[transfer full][element-type GstVideoCodecFrame]


gst_video_decoder_get_max_decode_time ()

GstClockTimeDiff
gst_video_decoder_get_max_decode_time (GstVideoDecoder *decoder,
                                       GstVideoCodecFrame *frame);

Determines maximum possible decoding time for frame that will allow it to decode and arrive in time (as determined by QoS events). In particular, a negative result means decoding in time is no longer possible and should therefore occur as soon/skippy as possible.

Parameters

decoder

a GstVideoDecoder

 

frame

a GstVideoCodecFrame

 

Returns

max decoding time.


gst_video_decoder_get_max_errors ()

gint
gst_video_decoder_get_max_errors (GstVideoDecoder *dec);

Parameters

dec

a GstVideoDecoder

 

Returns

currently configured decoder tolerated error count.


gst_video_decoder_get_oldest_frame ()

GstVideoCodecFrame *
gst_video_decoder_get_oldest_frame (GstVideoDecoder *decoder);

Get the oldest pending unfinished GstVideoCodecFrame

Parameters

decoder

a GstVideoDecoder

 

Returns

oldest pending unfinished GstVideoCodecFrame.

[transfer full]


gst_video_decoder_get_packetized ()

gboolean
gst_video_decoder_get_packetized (GstVideoDecoder *decoder);

Queries whether input data is considered packetized or not by the base class.

Parameters

decoder

a GstVideoDecoder

 

Returns

TRUE if input data is considered packetized.


gst_video_decoder_get_pending_frame_size ()

gsize
gst_video_decoder_get_pending_frame_size
                               (GstVideoDecoder *decoder);

Returns the number of bytes previously added to the current frame by calling gst_video_decoder_add_to_frame().

Parameters

decoder

a GstVideoDecoder

 

Returns

The number of bytes pending for the current frame

Since 1.4


gst_video_decoder_get_qos_proportion ()

gdouble
gst_video_decoder_get_qos_proportion (GstVideoDecoder *decoder);

Parameters

decoder

a GstVideoDecoder current QoS proportion, or NULL

 

Returns

The current QoS proportion.

Since 1.0.3


gst_video_decoder_have_frame ()

GstFlowReturn
gst_video_decoder_have_frame (GstVideoDecoder *decoder);

Gathers all data collected for currently parsed frame, gathers corresponding metadata and passes it along for further processing, i.e. handle_frame .

Parameters

decoder

a GstVideoDecoder

 

Returns

a GstFlowReturn


gst_video_decoder_get_latency ()

void
gst_video_decoder_get_latency (GstVideoDecoder *decoder,
                               GstClockTime *min_latency,
                               GstClockTime *max_latency);

Query the configured decoder latency. Results will be returned via min_latency and max_latency .

Parameters

decoder

a GstVideoDecoder

 

min_latency

address of variable in which to store the configured minimum latency, or NULL.

[out][allow-none]

max_latency

address of variable in which to store the configured mximum latency, or NULL.

[out][allow-none]

gst_video_decoder_set_latency ()

void
gst_video_decoder_set_latency (GstVideoDecoder *decoder,
                               GstClockTime min_latency,
                               GstClockTime max_latency);

Lets GstVideoDecoder sub-classes tell the baseclass what the decoder latency is. Will also post a LATENCY message on the bus so the pipeline can reconfigure its global latency.

Parameters

decoder

a GstVideoDecoder

 

min_latency

minimum latency

 

max_latency

maximum latency

 

gst_video_decoder_get_estimate_rate ()

gint
gst_video_decoder_get_estimate_rate (GstVideoDecoder *dec);

Parameters

dec

a GstVideoDecoder

 

Returns

currently configured byte to time conversion setting


gst_video_decoder_get_output_state ()

GstVideoCodecState *
gst_video_decoder_get_output_state (GstVideoDecoder *decoder);

Get the GstVideoCodecState currently describing the output stream.

Parameters

decoder

a GstVideoDecoder

 

Returns

GstVideoCodecState describing format of video data.

[transfer full]


gst_video_decoder_set_estimate_rate ()

void
gst_video_decoder_set_estimate_rate (GstVideoDecoder *dec,
                                     gboolean enabled);

Allows baseclass to perform byte to time estimated conversion.

Parameters

dec

a GstVideoDecoder

 

enabled

whether to enable byte to time conversion

 

gst_video_decoder_set_output_state ()

GstVideoCodecState *
gst_video_decoder_set_output_state (GstVideoDecoder *decoder,
                                    GstVideoFormat fmt,
                                    guint width,
                                    guint height,
                                    GstVideoCodecState *reference);

Creates a new GstVideoCodecState with the specified fmt , width and height as the output state for the decoder. Any previously set output state on decoder will be replaced by the newly created one.

If the subclass wishes to copy over existing fields (like pixel aspec ratio, or framerate) from an existing GstVideoCodecState, it can be provided as a reference .

If the subclass wishes to override some fields from the output state (like pixel-aspect-ratio or framerate) it can do so on the returned GstVideoCodecState.

The new output state will only take effect (set on pads and buffers) starting from the next call to gst_video_decoder_finish_frame().

Parameters

decoder

a GstVideoDecoder

 

fmt

a GstVideoFormat

 

width

The width in pixels

 

height

The height in pixels

 

reference

An optional reference GstVideoCodecState.

[allow-none][transfer none]

Returns

the newly configured output state.

[transfer full]


gst_video_decoder_set_max_errors ()

void
gst_video_decoder_set_max_errors (GstVideoDecoder *dec,
                                  gint num);

Sets numbers of tolerated decoder errors, where a tolerated one is then only warned about, but more than tolerated will lead to fatal error. You can set -1 for never returning fatal errors. Default is set to GST_VIDEO_DECODER_MAX_ERRORS.

The '-1' option was added in 1.4

Parameters

dec

a GstVideoDecoder

 

num

max tolerated errors

 

gst_video_decoder_set_packetized ()

void
gst_video_decoder_set_packetized (GstVideoDecoder *decoder,
                                  gboolean packetized);

Allows baseclass to consider input data as packetized or not. If the input is packetized, then the parse method will not be called.

Parameters

decoder

a GstVideoDecoder

 

packetized

whether the input data should be considered as packetized.

 

gst_video_decoder_get_needs_format ()

gboolean
gst_video_decoder_get_needs_format (GstVideoDecoder *dec);

Queries decoder required format handling.

Parameters

dec

a GstVideoDecoder

 

Returns

TRUE if required format handling is enabled.

Since 1.4


gst_video_decoder_set_needs_format ()

void
gst_video_decoder_set_needs_format (GstVideoDecoder *dec,
                                    gboolean enabled);

Configures decoder format needs. If enabled, subclass needs to be negotiated with format caps before it can process any data. It will then never be handed any data before it has been configured. Otherwise, it might be handed data without having been configured and is then expected being able to do so either by default or based on the input data.

Parameters

dec

a GstVideoDecoder

 

enabled

new state

 

Since 1.4


gst_video_decoder_merge_tags ()

void
gst_video_decoder_merge_tags (GstVideoDecoder *decoder,
                              const GstTagList *tags,
                              GstTagMergeMode mode);

Adds tags to so-called pending tags, which will be processed before pushing out data downstream.

Note that this is provided for convenience, and the subclass is not required to use this and can still do tag handling on its own.

MT safe.

Parameters

decoder

a GstVideoDecoder

 

tags

a GstTagList to merge

 

mode

the GstTagMergeMode to use

 

Types and Values

GST_VIDEO_DECODER_FLOW_NEED_DATA

#define GST_VIDEO_DECODER_FLOW_NEED_DATA GST_FLOW_CUSTOM_SUCCESS

Returned while parsing to indicate more data is needed.


GST_VIDEO_DECODER_MAX_ERRORS

#define GST_VIDEO_DECODER_MAX_ERRORS     10

Default maximum number of errors tolerated before signaling error.


GST_VIDEO_DECODER_SINK_NAME

#define GST_VIDEO_DECODER_SINK_NAME    "sink"

The name of the templates for the sink pad.


GST_VIDEO_DECODER_SRC_NAME

#define GST_VIDEO_DECODER_SRC_NAME     "src"

The name of the templates for the source pad.


struct GstVideoDecoder

struct GstVideoDecoder {
};

The opaque GstVideoDecoder data structure.


struct GstVideoDecoderClass

struct GstVideoDecoderClass {
  gboolean      (*open)           (GstVideoDecoder *decoder);

  gboolean      (*close)          (GstVideoDecoder *decoder);

  gboolean      (*start)          (GstVideoDecoder *decoder);

  gboolean      (*stop)           (GstVideoDecoder *decoder);

  GstFlowReturn (*parse)          (GstVideoDecoder *decoder,
				   GstVideoCodecFrame *frame,
				   GstAdapter *adapter,
				   gboolean at_eos);

  gboolean      (*set_format)     (GstVideoDecoder *decoder,
				   GstVideoCodecState * state);

  gboolean      (*reset)          (GstVideoDecoder *decoder,
				   gboolean hard);

  GstFlowReturn (*finish)         (GstVideoDecoder *decoder);

  GstFlowReturn (*handle_frame)   (GstVideoDecoder *decoder,
				   GstVideoCodecFrame *frame);

  gboolean      (*sink_event)     (GstVideoDecoder *decoder,
				   GstEvent *event);

  gboolean      (*src_event)      (GstVideoDecoder *decoder,
				   GstEvent *event);

  gboolean      (*negotiate)      (GstVideoDecoder *decoder);

  gboolean      (*decide_allocation)  (GstVideoDecoder *decoder, GstQuery *query);

  gboolean      (*propose_allocation) (GstVideoDecoder *decoder, GstQuery * query);

  gboolean      (*flush)              (GstVideoDecoder *decoder);

  gboolean      (*sink_query)     (GstVideoDecoder *decoder,
				   GstQuery *query);

  gboolean      (*src_query)      (GstVideoDecoder *decoder,
				   GstQuery *query);
};

Subclasses can override any of the available virtual methods or not, as needed. At minimum handle_frame needs to be overridden, and set_format and likely as well. If non-packetized input is supported or expected, parse needs to be overridden as well.

Members

open ()

Optional. Called when the element changes to GST_STATE_READY. Allows opening external resources.

 

close ()

Optional. Called when the element changes to GST_STATE_NULL. Allows closing external resources.

 

start ()

Optional. Called when the element starts processing. Allows opening external resources.

 

stop ()

Optional. Called when the element stops processing. Allows closing external resources.

 

parse ()

Required for non-packetized input. Allows chopping incoming data into manageable units (frames) for subsequent decoding.

 

set_format ()

Notifies subclass of incoming data format (caps).

 

reset ()

Optional. Allows subclass (decoder) to perform post-seek semantics reset. Deprecated.

 

finish ()

Optional. Called to request subclass to dispatch any pending remaining data (e.g. at EOS).

 

handle_frame ()

Provides input data frame to subclass.

 

sink_event ()

Optional. Event handler on the sink pad. This function should return TRUE if the event was handled and should be discarded (i.e. not unref'ed). Subclasses should chain up to the parent implementation to invoke the default handler.

 

src_event ()

Optional. Event handler on the source pad. This function should return TRUE if the event was handled and should be discarded (i.e. not unref'ed). Subclasses should chain up to the parent implementation to invoke the default handler.

 

negotiate ()

Optional. Negotiate with downstream and configure buffer pools, etc. Subclasses should chain up to the parent implementation to invoke the default handler.

 

decide_allocation ()

Optional. Setup the allocation parameters for allocating output buffers. The passed in query contains the result of the downstream allocation query. Subclasses should chain up to the parent implementation to invoke the default handler.

 

propose_allocation ()

Optional. Propose buffer allocation parameters for upstream elements. Subclasses should chain up to the parent implementation to invoke the default handler.

 

flush ()

Optional. Flush all remaining data from the decoder without pushing it downstream. Since: 1.2

 

sink_query ()

Optional. Query handler on the sink pad. This function should return TRUE if the query could be performed. Subclasses should chain up to the parent implementation to invoke the default handler. Since 1.4

 

src_query ()

Optional. Query handler on the source pad. This function should return TRUE if the query could be performed. Subclasses should chain up to the parent implementation to invoke the default handler. Since 1.4