GstCodecs.H264Decoder¶

Subclasses:: None

Methods¶

Inherited:: GstVideo.VideoDecoder (43), Gst.Element (82), Gst.Object (27), GObject.Object (37)
Structs:: Gst.ElementClass (10), GObject.ObjectClass (5)

	`get_picture` (system_frame_number)
	`set_process_ref_pic_lists` (process)

Virtual Methods¶

Inherited:: GstVideo.VideoDecoder (21), Gst.Element (16), Gst.Object (1), GObject.Object (7)

	`do_decode_slice` (picture, slice, ref_pic_list0, ref_pic_list1)
	`do_end_picture` (picture)
	`do_get_preferred_output_delay` (live)
	`do_new_field_picture` (first_field, second_field)
	`do_new_picture` (frame, picture)
	`do_output_picture` (frame, picture)
	`do_start_picture` (picture, slice, dpb)

Properties¶

Inherited:: GstVideo.VideoDecoder (6), Gst.Object (2)

Name	Type	Flags	Short Description
`compliance`	`GstCodecs.H264DecoderCompliance`	r/w/c	The decoder’s behavior in compliance with the h264 spec.

Signals¶

Inherited:: Gst.Element (3), Gst.Object (1), GObject.Object (1)

Fields¶

Inherited:: Gst.Element (3), Gst.Object (1), GObject.Object (1)

Name	Type	Access
input_state	`GstVideo.VideoCodecState`	r
padding	[`object`]	r
parent	`GstVideo.VideoDecoder`	r

Class Details¶

class GstCodecs.H264Decoder(**kwargs)¶

Bases:: GstVideo.VideoDecoder
Abstract:: Yes
Structure:: GstCodecs.H264DecoderClass

The opaque GstCodecs.H264Decoder data structure.

get_picture(system_frame_number)¶

Parameters:: system_frame_number (int) – a target system frame number of GstCodecs.H264Picture
Returns:: a GstCodecs.H264Picture if successful, or None otherwise
Return type:: GstCodecs.H264Picture or None

Retrive DPB and return a GstCodecs.H264Picture corresponding to the system_frame_number

New in version 1.18.

set_process_ref_pic_lists(process)¶

Parameters:: process (bool) – whether subclass is requiring reference picture modification process

Called to en/disable reference picture modification process.

New in version 1.18.

do_decode_slice(picture, slice, ref_pic_list0, ref_pic_list1) virtual¶

Parameters:

picture (GstCodecs.H264Picture) – a GstCodecs.H264Picture
slice (GstCodecs.H264Slice) – a GstCodecs.H264Slice
ref_pic_list0 ([GstCodecs.H264Picture]) – an array of GstCodecs.H264Picture pointers
ref_pic_list1 ([GstCodecs.H264Picture]) – an array of GstCodecs.H264Picture pointers

Return type:

Gst.FlowReturn

Provides per slice data with parsed slice header and required raw bitstream for subclass to decode it. If GstCodecs.H264Decoder.set_process_ref_pic_lists() is called with True by the subclass, ref_pic_list0 and ref_pic_list1 are non-None. In case of interlaced stream, ref_pic_list0 and ref_pic_list1 will contain only the first field of complementary reference field pair if currently being decoded picture is a frame picture. Subclasses might need to retrive the other field (i.e., the second field) of the picture if needed.

do_end_picture(picture) virtual¶

Parameters:: picture (GstCodecs.H264Picture) – a GstCodecs.H264Picture
Return type:: Gst.FlowReturn

Optional. Called per one GstCodecs.H264Picture to notify subclass to finish decoding process for the GstCodecs.H264Picture

do_get_preferred_output_delay(live) virtual¶

Parameters:: live (bool) – whether upstream is live or not
Returns:: the number of perferred delayed output frame
Return type:: int

Optional. Called by baseclass to query whether delaying output is preferred by subclass or not.

New in version 1.20.

do_new_field_picture(first_field, second_field) virtual¶

Parameters:

first_field (GstCodecs.H264Picture) – the first field GstCodecs.H264Picture already decoded
second_field (GstCodecs.H264Picture) – a GstCodecs.H264Picture for the second field

Return type:

Gst.FlowReturn

Called when a new field picture is created for interlaced field picture. Subclass can attach implementation specific user data on second_field via gst_h264_picture_set_user_data

New in version 1.20.

do_new_picture(frame, picture) virtual¶

Parameters:

frame (GstVideo.VideoCodecFrame) – a GstVideo.VideoCodecFrame
picture (GstCodecs.H264Picture) – a GstCodecs.H264Picture

Return type:

Gst.FlowReturn

Optional. Called whenever new GstCodecs.H264Picture is created. Subclass can set implementation specific user data on the GstCodecs.H264Picture via gst_h264_picture_set_user_data

do_output_picture(frame, picture) virtual¶

Parameters:

frame (GstVideo.VideoCodecFrame) – a GstVideo.VideoCodecFrame
picture (GstCodecs.H264Picture) – a GstCodecs.H264Picture

Return type:

Gst.FlowReturn

Called with a GstCodecs.H264Picture which is required to be outputted. The GstVideo.VideoCodecFrame must be consumed by subclass.

do_start_picture(picture, slice, dpb) virtual¶

Parameters:

picture (GstCodecs.H264Picture) – a GstCodecs.H264Picture
slice (GstCodecs.H264Slice) – a GstCodecs.H264Slice
dpb (GstCodecs.H264Dpb) – a GstCodecs.H264Dpb

Return type:

Gst.FlowReturn

Optional. Called per one GstCodecs.H264Picture to notify subclass to prepare decoding process for the GstCodecs.H264Picture

Property Details¶

GstCodecs.H264Decoder.props.compliance¶

Name:: compliance
Type:: GstCodecs.H264DecoderCompliance
Default Value:: GstCodecs.H264DecoderCompliance.AUTO
Flags:: READABLE, WRITABLE, CONSTRUCT

The compliance controls the behavior of the decoder to handle some subtle cases and contexts, such as the low-latency DPB bumping or mapping the baseline profile as the constrained-baseline profile, etc.

New in version 1.20.