Removes next n_bytes of input data and adds it to currently parsed frame.
Helper function that allocates a buffer to hold a video frame for decoder's current #GstVideoCodecState.
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.
Same as #gst_video_decoder_allocate_output_frame except it allows passing #GstBufferPoolAcquireParams to the sub call gst_buffer_pool_acquire_buffer.
Similar to gstvideo.video_decoder.VideoDecoder.finishFrame, 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.
Drops input data. The frame is not considered finished until the whole frame is finished or dropped by the subclass.
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.
Indicate that a subframe has been finished to be decoded by the subclass. This method should be called for all subframes except the last subframe where gst_video_decoder_finish_frame should be called instead.
Lets #GstVideoDecoder sub-classes to know the memory allocator used by the base class and its params.
Get a pending unfinished #GstVideoCodecFrame
Get all pending unfinished #GstVideoCodecFrame
Queries the number of the last subframe received by the decoder baseclass in the frame.
Query the configured decoder latency. Results will be returned via min_latency and max_latency.
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.
Queries decoder required format handling.
Queries if the decoder requires a sync point before it starts outputting data in the beginning.
Get the oldest pending unfinished #GstVideoCodecFrame
Get the #GstVideoCodecState currently describing the output stream.
Queries whether input data is considered packetized or not by the base class.
Returns the number of bytes previously added to the current frame by calling gstvideo.video_decoder.VideoDecoder.addToFrame.
Queries the number of subframes in the frame processed by the decoder baseclass.
Queries whether input data is considered as subframes or not by the base class. If FALSE, each input buffer will be considered as a full frame.
Gathers all data collected for currently parsed frame, gathers corresponding metadata and passes it along for further processing, i.e. handle_frame.
Indicates that the last subframe has been processed by the decoder in frame. This will release the current frame in video decoder allowing to receive new frames from upstream elements. This method must be called in the subclass handle_frame callback.
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 #GstVideoCodecState. 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 resolution/format/... combinations supported by downstream elements.
Similar to gstvideo.video_decoder.VideoDecoder.dropFrame, but simply releases frame without any processing other than removing it from list of pending frames, after which it is considered finished and released.
Allows the #GstVideoDecoder subclass to request from the base class that a new sync should be requested from upstream, and that frame was the frame when the subclass noticed that a new sync point is required. A reason for the subclass to do this could be missing reference frames, for example.
Allows baseclass to perform byte to time estimated conversion.
Same as #gstvideo.video_decoder.VideoDecoder.setOutputState but also allows you to also set the interlacing mode.
Lets #GstVideoDecoder sub-classes tell the baseclass what the decoder latency is. 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_VIDEO_DECODER_MAX_ERRORS.
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.
Configures whether the decoder requires a sync point before it starts outputting data in the beginning. If enabled, the base class will discard all non-sync point frames in the beginning and after a flush and does not pass it to the subclass.
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.
Allows baseclass to consider input data as packetized or not. If the input is packetized, then the parse method will not be called.
If this is set to TRUE, it informs the base class that the subclass can receive the data at a granularity lower than one frame.
Lets #GstVideoDecoder 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 video decoders turning encoded data into raw video frames.
The GstVideoDecoder base class and derived subclasses should cooperate as follows:
Configuration
Data processing
Shutdown phase
Additional Notes
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 output 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: