Helper function that allocates a buffer to hold an audio frame for dec's current output format.
Collects decoded data and pushes it downstream.
Collects decoded data and pushes it downstream. This function may be called multiple times for a given input frame.
Lets #GstAudioDecoder sub-classes to know the memory allocator used by the base class and its params.
Queries decoder drain handling.
Sets the variables pointed to by min and max to the currently configured latency.
Queries decoder's latency aggregation.
Queries decoder required format handling.
Return current parsing (sync and eos) state.
Queries decoder packet loss concealment handling.
Queries current audio jitter tolerance threshold.
Sets the audio decoder tags and how they should be merged with any upstream stream tags. This will override any tags previously-set with gstaudio.audio_decoder.AudioDecoder.mergeTags.
Negotiate with downstream elements to currently configured #GstAudioInfo. Unmark GST_PAD_FLAG_NEED_RECONFIGURE in any case. But mark it again if negotiate fails.
Returns caps that express caps (or sink template caps if caps == NULL) restricted to rate/channels/... combinations supported by downstream elements.
Sets a caps in allocation query which are different from the set pad's caps. Use this function before calling gstaudio.audio_decoder.AudioDecoder.negotiate. Setting to null the allocation query will use the caps from the pad.
Configures decoder drain handling. If drainable, subclass might be handed a NULL buffer to have it return any leftover decoded data. Otherwise, it is not considered so capable and will only ever be passed real data.
Allows baseclass to perform byte to time estimated conversion.
Sets decoder latency. If the provided values changed from previously provided ones, this will also post a LATENCY message on the bus so the pipeline can reconfigure its global latency.
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_AUDIO_DECODER_MAX_ERRORS.
Sets decoder minimum aggregation latency.
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.
Configure output caps on the srcpad of dec. Similar to gstaudio.audio_decoder.AudioDecoder.setOutputFormat, but allows subclasses to specify output caps that can't be expressed via #GstAudioInfo e.g. caps that have caps features.
Configure output info on the srcpad of dec.
Enable or disable decoder packet loss concealment, provided subclass and codec are capable and allow handling plc.
Indicates whether or not subclass handles packet loss concealment (plc).
Configures decoder audio jitter tolerance threshold.
Lets #GstAudioDecoder sub-classes decide if they want the sink pad to use the default pad query handler to reply to accept-caps queries.
Creates an element for handling the given URI.
Create a new elementfactory capable of instantiating objects of the type and add the factory to plugin.
Gets a string representing the given state change result.
Gets a string representing the given state.
Marks type as "documentation should be skipped". Can be useful for dynamically registered element to be excluded from plugin documentation system.
Abort the state change of the element. This function is used by elements that do asynchronous state changes and find out something is wrong.
Adds a pad (link point) to element. pad's parent will be set to element; see gst.object.ObjectGst.setParent for refcounting information.
Calls func from another thread and passes user_data to it. This is to be used for cases when a state change has to be performed from a streaming thread, directly via gst.element.Element.setState or indirectly e.g. via SEEK events.
Perform transition on element.
Commit the state change of the element and proceed to the next pending state if any. This function is used by elements that do asynchronous state changes. The core will normally call this method automatically when an element returned gst.types.StateChangeReturn.Success from the state change function.
Creates a pad for each pad template that is always available. This function is only useful during object initialization of subclasses of #GstElement.
Creates a stream-id for element by combining the upstream information with the stream_id.
Call func with user_data for each of element's pads. func will be called exactly once for each pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new pads are added or pads are removed while pads are being iterated, this will not be taken into account until next time this function is used.
Call func with user_data for each of element's sink pads. func will be called exactly once for each sink pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new sink pads are added or sink pads are removed while the sink pads are being iterated, this will not be taken into account until next time this function is used.
Call func with user_data for each of element's source pads. func will be called exactly once for each source pad that exists at the time of this call, unless one of the calls to func returns false in which case we will stop iterating pads and return early. If new source pads are added or source pads are removed while the source pads are being iterated, this will not be taken into account until next time this function is used.
Returns the base time of the element. The base time is the absolute time of the clock when this element was last put to PLAYING. Subtracting the base time from the clock time gives the running time of the element.
Returns the bus of the element. Note that only a #GstPipeline will provide a bus for the application.
Gets the currently configured clock of the element. This is the clock as was last set with gst.element.Element.setClock.
Looks for an unlinked pad to which the given pad can link. It is not guaranteed that linking the pads will work, though it should work in most cases.
Retrieves a pad template from element that is compatible with compattempl. Pads from compatible templates can be linked together.
Gets the context with context_type set on the element or NULL.
Gets the context with context_type set on the element or NULL.
Gets the contexts set on the element.
Returns the current clock time of the element, as in, the time of the element's clock, or GST_CLOCK_TIME_NONE if there is no clock.
Returns the running time of the element. The running time is the element's clock time minus its base time. Will return GST_CLOCK_TIME_NONE if the element has no clock, or if its base time has not been set.
Retrieves the factory that was used to create this element.
Get metadata with key in klass.
Retrieves a padtemplate from element with the given name.
Retrieves a list of the pad templates associated with element. The list must not be modified by the calling code.
The name of this function is confusing to people learning GStreamer. gst.element.Element.requestPadSimple aims at making it more explicit it is a simplified gst.element.Element.requestPad.
Returns the start time of the element. The start time is the running time of the clock when this element was last put to PAUSED.
Gets the state of the element.
Retrieves a pad from element by name. This version only retrieves already-existing (i.e. 'static') pads.
Checks if the state of an element is locked. If the state of an element is locked, state changes of the parent don't affect the element. This way you can leave currently unused elements inside bins. Just lock their state before changing the state from #GST_STATE_NULL.
Retrieves an iterator of element's pads. The iterator should be freed after usage. Also more specialized iterators exists such as gst.element.Element.iterateSrcPads or gst.element.Element.iterateSinkPads.
Retrieves an iterator of element's sink pads.
Retrieves an iterator of element's source pads.
Links src to dest. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. Such pads need to be released manually when unlinking. If multiple links are possible, only one is established.
Links src to dest using the given caps as filtercaps. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. If multiple links are possible, only one is established.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails. If caps is not null, makes sure that the caps of the link is a subset of caps.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails.
Brings the element to the lost state. The current state of the element is copied to the pending state so that any call to gst.element.Element.getState will return gst.types.StateChangeReturn.Async.
Post an error, warning or info message on the bus from inside an element.
Post an error, warning or info message on the bus from inside an element.
Use this function to signal that the element does not expect any more pads to show up in the current pipeline. This function should be called whenever pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES pad templates use this in combination with autopluggers to figure out that the element is done initializing its pads.
Post a message on the element's #GstBus. This function takes ownership of the message; if you want to access the message after this call, you should add an additional reference before calling.
Get the clock provided by the given element. > An element is only required to provide a clock in the PAUSED > state. Some elements can provide a clock in other states.
Performs a query on the given element.
Queries an element to convert src_val in src_format to dest_format.
Queries an element (usually top-level pipeline or playbin element) for the total stream duration in nanoseconds. This query will only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case.
Queries an element (usually top-level pipeline or playbin element) for the stream position in nanoseconds. This will be a value between 0 and the stream duration (if the stream duration is known). This query will usually only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case.
Makes the element free the previously requested pad as obtained with gst.element.Element.requestPad.
Removes pad from element. pad will be destroyed if it has not been referenced elsewhere using gst.object.ObjectGst.unparent.
Retrieves a request pad from the element according to the provided template. Pad templates can be looked up using gst.element_factory.ElementFactory.getStaticPadTemplates.
Retrieves a pad from the element by name (e.g. "src_\d"). This version only retrieves request pads. The pad should be released with gst.element.Element.releaseRequestPad.
Sends a seek event to an element. See gst.event.Event.newSeek for the details of the parameters. The seek event is sent to the element using gst.element.Element.sendEvent.
Simple API to perform a seek on the given element, meaning it just seeks to the given position relative to the start of the stream. For more complex operations like segment seeks (e.g. for looping) or changing the playback rate or seeking relative to the last configured playback segment you should use gst.element.Element.seek.
Sends an event to an element. If the element doesn't implement an event handler, the event will be pushed on a random linked sink pad for downstream events or a random linked source pad for upstream events.
Set the base time of an element. See gst.element.Element.getBaseTime.
Sets the bus of the element. Increases the refcount on the bus. For internal use only, unless you're testing elements.
Sets the clock for the element. This function increases the refcount on the clock. Any previously set clock on the object is unreffed.
Sets the context of the element. Increases the refcount of the context.
Locks the state of an element, so state changes of the parent don't affect this element anymore.
Set the start time of an element. The start time of the element is the running time of the element when it last went to the PAUSED state. In READY or after a flushing seek, it is set to 0.
Sets the state of the element. This function will try to set the requested state by going through all the intermediary states and calling the class's state change function for each.
Tries to change the state of the element to the same as its parent. If this function returns false, the state of element is undefined.
Unlinks all source pads of the source element with all sink pads of the sink element to which they are linked.
Unlinks the two named pads of the source and destination elements.
Connect to NoMorePads signal.
Connect to PadAdded signal.
Connect to PadRemoved signal.
This base class is for audio decoders turning encoded data into raw audio samples.
GstAudioDecoder and subclass should cooperate as follows.
Configuration
As of configuration stage, and throughout processing, GstAudioDecoder provides various (context) parameters, e.g. describing the format of output audio data (valid when output caps have been set) or current parsing state. Conversely, subclass can and should configure context to inform base class of its expectation w.r.t. buffer handling.
Data processing
Shutdown phase
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 set the fixed caps on srcpad, when the format is ensured. This is typically when base class calls subclass' @set_format function, though it might be delayed until calling @gst_audio_decoder_finish_frame.
In summary, above process should have subclass concentrating on codec data processing while leaving other matters to base class, such as most notably timestamp handling. While it may exert more control in this area (see e.g. @pre_push), it is very much not recommended.
In particular, base class will try to arrange for perfect output timestamps as much as possible while tracking upstream timestamps. To this end, if deviation between the next ideal expected perfect timestamp and upstream exceeds #GstAudioDecoder:tolerance, then resync to upstream occurs (which would happen always if the tolerance mechanism is disabled).
In non-live pipelines, baseclass can also (configurably) arrange for output buffer aggregation which may help to redue large(r) numbers of small(er) buffers being pushed and processed downstream. Note that this feature is only available if the buffer layout is interleaved. For planar buffers, the decoder implementation is fully responsible for the output buffer size.
On the other hand, it should be noted that baseclass only provides limited seeking support (upon explicit subclass request), 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.
Things that subclass need to take care of: