#include <stddef.h>
#include <stdint.h>
#include "libavutil/buffer.h"
#include "codec_id.h"
#include "codec_par.h"
#include "defs.h"
#include "packet.h"

Data Structures
struct	CodedBitstreamUnit
	Coded bitstream unit structure. More...

struct	CodedBitstreamFragment
	Coded bitstream fragment structure, combining one or more units. More...

struct	CodedBitstreamContext
	Context structure for coded bitstream operations. More...

Macros
#define	CBS_PREFIX cbs

#define	CBS_FUNC_PREFIX_NAME(prefix, name) ff_ ## prefix ## _ ## name

#define	CBS_FUNC_NAME(prefix, name) CBS_FUNC_PREFIX_NAME(prefix, name)

#define	CBS_FUNC(name) CBS_FUNC_NAME(CBS_PREFIX, name)

Typedefs
typedef uint32_t	CodedBitstreamUnitType
	The codec-specific type of a bitstream unit. More...

typedef void(*	CBSTraceReadCallback) (void trace_context, struct GetBitContext gbc, int start_position, const char name, const int subscripts, int64_t value)
	Callback type for read tracing. More...

typedef void(*	CBSTraceWriteCallback) (void trace_context, struct PutBitContext pbc, int start_position, const char name, const int subscripts, int64_t value)
	Callback type for write tracing. More...

Enumerations
enum	CbsDiscardFlags { DISCARD_FLAG_NONE = 0, DISCARD_FLAG_KEEP_NON_VCL = 0x01 }

Functions
enum AVCodecID	CBS_FUNC (all_codec_ids)[]
	Table of all supported codec IDs. More...

int CBS_FUNC()	init (CodedBitstreamContext *ctx, enum AVCodecID codec_id, void log_ctx)
	Create and initialise a new context for the given codec. More...

void CBS_FUNC()	flush (CodedBitstreamContext *ctx)
	Reset all internal state in a context. More...

void CBS_FUNC()	close (CodedBitstreamContext **ctx)
	Close a context and free all internal state. More...

int CBS_FUNC()	read_extradata (CodedBitstreamContext ctx, CodedBitstreamFragment frag, const AVCodecParameters *par)
	Read the extradata bitstream found in codec parameters into a fragment, then split into units and decompose. More...

int CBS_FUNC()	read_extradata_from_codec (CodedBitstreamContext ctx, CodedBitstreamFragment frag, const struct AVCodecContext *avctx)
	Read the extradata bitstream found in a codec context into a fragment, then split into units and decompose. More...

int CBS_FUNC()	read_packet_side_data (CodedBitstreamContext ctx, CodedBitstreamFragment frag, const AVPacket *pkt)

int CBS_FUNC()	read_packet (CodedBitstreamContext ctx, CodedBitstreamFragment frag, const AVPacket *pkt)
	Read the data bitstream from a packet into a fragment, then split into units and decompose. More...

int CBS_FUNC()	read (CodedBitstreamContext ctx, CodedBitstreamFragment frag, const uint8_t *data, size_t size)
	Read a bitstream from a memory region into a fragment, then split into units and decompose. More...

int CBS_FUNC()	write_fragment_data (CodedBitstreamContext ctx, CodedBitstreamFragment frag)
	Write the content of the fragment to its own internal buffer. More...

int CBS_FUNC()	write_extradata (CodedBitstreamContext ctx, AVCodecParameters par, CodedBitstreamFragment *frag)
	Write the bitstream of a fragment to the extradata in codec parameters. More...

int CBS_FUNC()	write_packet (CodedBitstreamContext ctx, AVPacket pkt, CodedBitstreamFragment *frag)
	Write the bitstream of a fragment to a packet. More...

void CBS_FUNC()	fragment_reset (CodedBitstreamFragment *frag)
	Free the units contained in a fragment as well as the fragment's own data buffer, but not the units array itself. More...

void CBS_FUNC()	fragment_free (CodedBitstreamFragment *frag)
	Free the units array of a fragment in addition to what ff_cbs_fragment_reset does. More...

int CBS_FUNC()	alloc_unit_content (CodedBitstreamContext ctx, CodedBitstreamUnit unit)
	Allocate a new internal content buffer matching the type of the unit. More...

int CBS_FUNC()	insert_unit_content (CodedBitstreamFragment frag, int position, CodedBitstreamUnitType type, void content, void *content_ref)
	Insert a new unit into a fragment with the given content. More...

int CBS_FUNC()	append_unit_data (CodedBitstreamFragment frag, CodedBitstreamUnitType type, uint8_t data, size_t data_size, AVBufferRef *data_buf)
	Add a new unit to a fragment with the given data bitstream. More...

void CBS_FUNC()	delete_unit (CodedBitstreamFragment *frag, int position)
	Delete a unit from a fragment and free all memory it uses. More...

int CBS_FUNC()	make_unit_refcounted (CodedBitstreamContext ctx, CodedBitstreamUnit unit)
	Make the content of a unit refcounted. More...

int CBS_FUNC()	make_unit_writable (CodedBitstreamContext ctx, CodedBitstreamUnit unit)
	Make the content of a unit writable so that internal fields can be modified. More...

void CBS_FUNC()	discard_units (CodedBitstreamContext ctx, CodedBitstreamFragment frag, enum AVDiscard skip, int flags)
	Discard units accroding to 'skip'. More...

void CBS_FUNC()	trace_read_log (void trace_context, struct GetBitContext gbc, int length, const char str, const int subscripts, int64_t value)
	Helper function for read tracing which formats the syntax element and logs the result. More...

void CBS_FUNC()	trace_write_log (void trace_context, struct PutBitContext pbc, int length, const char str, const int subscripts, int64_t value)
	Helper function for write tracing which formats the syntax element and logs the result. More...

Macro Definition Documentation

◆ CBS_PREFIX

#define CBS_PREFIX cbs

Definition at line 33 of file cbs.h.

◆ CBS_FUNC_PREFIX_NAME

#define CBS_FUNC_PREFIX_NAME	(	prefix,
		name
	)	ff_ ## prefix ## _ ## name

Definition at line 36 of file cbs.h.

◆ CBS_FUNC_NAME

#define CBS_FUNC_NAME	(	prefix,
		name
	)	CBS_FUNC_PREFIX_NAME(prefix, name)

Definition at line 37 of file cbs.h.

◆ CBS_FUNC

#define CBS_FUNC ( name ) CBS_FUNC_NAME(CBS_PREFIX, name)

Definition at line 38 of file cbs.h.

Typedef Documentation

◆ CodedBitstreamUnitType

typedef uint32_t CodedBitstreamUnitType

The codec-specific type of a bitstream unit.

AV1: obu_type H.264 / AVC: nal_unit_type H.265 / HEVC: nal_unit_type JPEG: marker value (without 0xff prefix) MPEG-2: start code value (without prefix) VP9: unused, set to zero (every unit is a frame)

Definition at line 54 of file cbs.h.

◆ CBSTraceReadCallback

typedef void(* CBSTraceReadCallback) (void *trace_context, struct GetBitContext *gbc, int start_position, const char *name, const int *subscripts, int64_t value)

Callback type for read tracing.

Parameters

ctx	User-set trace context.
gbc	A GetBitContext set at the start of the syntax element. This is a copy, the callee does not need to preserve it.
length	Length in bits of the syntax element.
name	String name of the syntax elements.
subscripts	If the syntax element is an array, a pointer to an array of subscripts into the array.
value	Parsed value of the syntax element.

Definition at line 196 of file cbs.h.

◆ CBSTraceWriteCallback

typedef void(* CBSTraceWriteCallback) (void *trace_context, struct PutBitContext *pbc, int start_position, const char *name, const int *subscripts, int64_t value)

Callback type for write tracing.

Parameters

ctx	User-set trace context.
pbc	A PutBitContext set at the end of the syntax element. The user must not modify this, but may inspect it to determine state.
length	Length in bits of the syntax element.
name	String name of the syntax elements.
subscripts	If the syntax element is an array, a pointer to an array of subscripts into the array.
value	Written value of the syntax element.

Definition at line 216 of file cbs.h.

Enumeration Type Documentation

◆ CbsDiscardFlags

enum CbsDiscardFlags

Enumerator
DISCARD_FLAG_NONE
DISCARD_FLAG_KEEP_NON_VCL	keep non-vcl units even if the picture has been dropped.

Definition at line 508 of file cbs.h.

Function Documentation

◆ CBS_FUNC()

enum AVCodecID CBS_FUNC ( all_codec_ids )

Table of all supported codec IDs.

Terminated by AV_CODEC_ID_NONE.

◆ init()

int CBS_FUNC() init	(	CodedBitstreamContext **	ctx,
		enum AVCodecID	codec_id,
		void *	log_ctx
	)

Create and initialise a new context for the given codec.

Definition at line 88 of file cbs.c.

◆ flush()

void CBS_FUNC() flush ( CodedBitstreamContext * ctx )

Reset all internal state in a context.

Definition at line 134 of file cbs.c.

Referenced by trace_write_log().

◆ close()

void CBS_FUNC() close ( CodedBitstreamContext ** ctx )

Close a context and free all internal state.

Definition at line 140 of file cbs.c.

Referenced by av_file_map(), avformat_open_input(), bench_uninit(), cache_close(), check(), drm_device_create(), drm_device_free(), fbdev_read_close(), fbdev_read_header(), fbdev_write_header(), fbdev_write_trailer(), ff_ass_split_override_codes(), ff_fbdev_get_device_list(), ff_get_cpu_flags_ppc(), ff_oss_audio_close(), ff_oss_audio_open(), file_close(), kmsgrab_free_desc(), main(), mov_text_style_cb(), srt_stack_push_pop(), srt_style_cb(), v4l2_configure_contexts(), v4l2_m2m_destroy_context(), v4l2_probe_driver(), vaapi_device_create(), vaapi_device_derive(), vaapi_device_free(), webvtt_stack_push_pop(), webvtt_style_cb(), write_trailer(), and xvid_encode_close().

◆ read_extradata()

int CBS_FUNC() read_extradata	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		const AVCodecParameters *	par
	)

Read the extradata bitstream found in codec parameters into a fragment, then split into units and decompose.

This also updates the internal state, so will need to be called for codecs with extradata to read parameter sets necessary for further parsing even if the fragment itself is not desired.

The fragment must have been zeroed or reset via ff_cbs_fragment_reset before use.

Definition at line 285 of file cbs.c.

◆ read_extradata_from_codec()

int CBS_FUNC() read_extradata_from_codec	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		const struct AVCodecContext *	avctx
	)

Read the extradata bitstream found in a codec context into a fragment, then split into units and decompose.

This acts identical to ff_cbs_read_extradata() for the case where you already have a codec context.

◆ read_packet_side_data()

int CBS_FUNC() read_packet_side_data	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		const AVPacket *	pkt
	)

Definition at line 311 of file cbs.c.

◆ read_packet()

int CBS_FUNC() read_packet	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		const AVPacket *	pkt
	)

Read the data bitstream from a packet into a fragment, then split into units and decompose.

This also updates the internal state of the coded bitstream context with any persistent data from the fragment which may be required to read following fragments (e.g. parameter sets).

The fragment must have been zeroed or reset via ff_cbs_fragment_reset before use.

Definition at line 303 of file cbs.c.

◆ read()

int CBS_FUNC() read	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		const uint8_t *	data,
		size_t	size
	)

Read a bitstream from a memory region into a fragment, then split into units and decompose.

This also updates the internal state of the coded bitstream context with any persistent data from the fragment which may be required to read following fragments (e.g. parameter sets).

The fragment must have been zeroed or reset via ff_cbs_fragment_reset before use.

Definition at line 324 of file cbs.c.

◆ write_fragment_data()

int CBS_FUNC() write_fragment_data	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag
	)

Write the content of the fragment to its own internal buffer.

Writes the content of all units and then assembles them into a new data buffer. When modifying the content of decomposed units, this can be used to regenerate the bitstream form of units or the whole fragment so that it can be extracted for other use.

This also updates the internal state of the coded bitstream context with any persistent data from the fragment which may be required to write following fragments (e.g. parameter sets).

Definition at line 410 of file cbs.c.

Referenced by write_extradata(), and write_packet().

◆ write_extradata()

int CBS_FUNC() write_extradata	(	CodedBitstreamContext *	ctx,
		AVCodecParameters *	par,
		CodedBitstreamFragment *	frag
	)

Write the bitstream of a fragment to the extradata in codec parameters.

Modifies context and fragment as ff_cbs_write_fragment_data does and replaces any existing extradata in the structure.

Definition at line 446 of file cbs.c.

◆ write_packet()

int CBS_FUNC() write_packet	(	CodedBitstreamContext *	ctx,
		AVPacket *	pkt,
		CodedBitstreamFragment *	frag
	)

Write the bitstream of a fragment to a packet.

Modifies context and fragment as ff_cbs_write_fragment_data does.

On success, the packet's buf is unreferenced and its buf, data and size fields are set to the corresponding values from the newly updated fragment; other fields are not touched. On failure, the packet is not touched at all.

Definition at line 475 of file cbs.c.

◆ fragment_reset()

void CBS_FUNC() fragment_reset ( CodedBitstreamFragment * frag )

Free the units contained in a fragment as well as the fragment's own data buffer, but not the units array itself.

Definition at line 170 of file cbs.c.

Referenced by fragment_free().

◆ fragment_free()

void CBS_FUNC() fragment_free ( CodedBitstreamFragment * frag )

Free the units array of a fragment in addition to what ff_cbs_fragment_reset does.

Definition at line 184 of file cbs.c.

Referenced by discard_units().

◆ alloc_unit_content()

int CBS_FUNC() alloc_unit_content	(	CodedBitstreamContext *	ctx,
		CodedBitstreamUnit *	unit
	)

Allocate a new internal content buffer matching the type of the unit.

The content will be zeroed.

Definition at line 939 of file cbs.c.

Referenced by cbs_av1_read_unit().

◆ insert_unit_content()

int CBS_FUNC() insert_unit_content	(	CodedBitstreamFragment *	frag,
		int	position,
		CodedBitstreamUnitType	type,
		void *	content,
		void *	content_ref
	)

Insert a new unit into a fragment with the given content.

If content_ref is supplied, it has to be a RefStruct reference backing content; the user keeps ownership of the supplied reference. The content structure continues to be owned by the caller if content_ref is not supplied.

Definition at line 799 of file cbs.c.

◆ append_unit_data()

int CBS_FUNC() append_unit_data	(	CodedBitstreamFragment *	frag,
		CodedBitstreamUnitType	type,
		uint8_t *	data,
		size_t	data_size,
		AVBufferRef *	data_buf
	)

Add a new unit to a fragment with the given data bitstream.

If data_buf is not supplied then data must have been allocated with av_malloc() and will on success become owned by the unit after this call or freed on error.

Definition at line 866 of file cbs.c.

Referenced by cbs_av1_split_fragment().

◆ delete_unit()

void CBS_FUNC() delete_unit	(	CodedBitstreamFragment *	frag,
		int	position
	)

Delete a unit from a fragment and free all memory it uses.

Requires position to be >= 0 and < frag->nb_units.

Definition at line 876 of file cbs.c.

Referenced by discard_units().

◆ make_unit_refcounted()

int CBS_FUNC() make_unit_refcounted	(	CodedBitstreamContext *	ctx,
		CodedBitstreamUnit *	unit
	)

Make the content of a unit refcounted.

If the unit is not refcounted, this will do a deep copy of the unit content to new refcounted buffers.

It is not valid to call this function on a unit which does not have decomposed content.

Definition at line 1051 of file cbs.c.

Referenced by cbs_av1_write_obu().

◆ make_unit_writable()

int CBS_FUNC() make_unit_writable	(	CodedBitstreamContext *	ctx,
		CodedBitstreamUnit *	unit
	)

Make the content of a unit writable so that internal fields can be modified.

If it is known that there are no other references to the content of the unit, does nothing and returns success. Otherwise (including the case where the unit content is not refcounted), it does a full clone of the content (including any internal buffers) to make a new copy, and replaces the existing references inside the unit with that.

It is not valid to call this function on a unit which does not have decomposed content.

Definition at line 1060 of file cbs.c.

◆ discard_units()

void CBS_FUNC() discard_units	(	CodedBitstreamContext *	ctx,
		CodedBitstreamFragment *	frag,
		enum AVDiscard	skip,
		int	flags
	)

Discard units accroding to 'skip'.

Definition at line 1077 of file cbs.c.

◆ trace_read_log()

void CBS_FUNC() trace_read_log	(	void *	trace_context,
		struct GetBitContext *	gbc,
		int	length,
		const char *	str,
		const int *	subscripts,
		int64_t	value
	)

Helper function for read tracing which formats the syntax element and logs the result.

Trace context should be set to the CodedBitstreamContext.

Definition at line 512 of file cbs.c.

Referenced by trace_write_log().

◆ trace_write_log()

void CBS_FUNC() trace_write_log	(	void *	trace_context,
		struct PutBitContext *	pbc,
		int	length,
		const char *	str,
		const int *	subscripts,
		int64_t	value
	)

Helper function for write tracing which formats the syntax element and logs the result.

Trace context should be set to the CodedBitstreamContext.

Definition at line 572 of file cbs.c.

Data Structures

Macros

Typedefs

Enumerations

Functions

Macro Definition Documentation

◆ CBS_PREFIX

◆ CBS_FUNC_PREFIX_NAME

◆ CBS_FUNC_NAME

◆ CBS_FUNC

Typedef Documentation

◆ CodedBitstreamUnitType

◆ CBSTraceReadCallback

◆ CBSTraceWriteCallback

Enumeration Type Documentation

◆ CbsDiscardFlags

Function Documentation

◆ CBS_FUNC()

◆ init()

◆ flush()

◆ close()

◆ read_extradata()

◆ read_extradata_from_codec()

◆ read_packet_side_data()

◆ read_packet()

◆ read()

◆ write_fragment_data()

◆ write_extradata()

◆ write_packet()

◆ fragment_reset()

◆ fragment_free()

◆ alloc_unit_content()

◆ insert_unit_content()

◆ append_unit_data()

◆ delete_unit()

◆ make_unit_refcounted()

◆ make_unit_writable()

◆ discard_units()

◆ trace_read_log()

◆ trace_write_log()