FFmpeg
Data Structures | Typedefs | Enumerations | Functions | Variables
cbs.h File Reference
#include <stddef.h>
#include <stdint.h>
#include "libavutil/buffer.h"
#include "codec_id.h"
#include "codec_par.h"
#include "defs.h"
#include "packet.h"

Go to the source code of this file.

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...
 

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

int ff_cbs_init (CodedBitstreamContext **ctx, enum AVCodecID codec_id, void *log_ctx)
 Create and initialise a new context for the given codec. More...
 
void ff_cbs_flush (CodedBitstreamContext *ctx)
 Reset all internal state in a context. More...
 
void ff_cbs_close (CodedBitstreamContext **ctx)
 Close a context and free all internal state. More...
 
int ff_cbs_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 ff_cbs_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 ff_cbs_read_packet_side_data (CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, const AVPacket *pkt)
 
int ff_cbs_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 ff_cbs_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 ff_cbs_write_fragment_data (CodedBitstreamContext *ctx, CodedBitstreamFragment *frag)
 Write the content of the fragment to its own internal buffer. More...
 
int ff_cbs_write_extradata (CodedBitstreamContext *ctx, AVCodecParameters *par, CodedBitstreamFragment *frag)
 Write the bitstream of a fragment to the extradata in codec parameters. More...
 
int ff_cbs_write_packet (CodedBitstreamContext *ctx, AVPacket *pkt, CodedBitstreamFragment *frag)
 Write the bitstream of a fragment to a packet. More...
 
void ff_cbs_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 ff_cbs_fragment_free (CodedBitstreamFragment *frag)
 Free the units array of a fragment in addition to what ff_cbs_fragment_reset does. More...
 
int ff_cbs_alloc_unit_content (CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
 Allocate a new internal content buffer matching the type of the unit. More...
 
int ff_cbs_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 ff_cbs_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 ff_cbs_delete_unit (CodedBitstreamFragment *frag, int position)
 Delete a unit from a fragment and free all memory it uses. More...
 
int ff_cbs_make_unit_refcounted (CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
 Make the content of a unit refcounted. More...
 
int ff_cbs_make_unit_writable (CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
 Make the content of a unit writable so that internal fields can be modified. More...
 
void ff_cbs_discard_units (CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, enum AVDiscard skip, int flags)
 Discard units accroding to 'skip'. More...
 
void ff_cbs_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 ff_cbs_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...
 

Variables

enum AVCodecID ff_cbs_all_codec_ids []
 Table of all supported codec IDs. More...
 

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 47 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
ctxUser-set trace context.
gbcA GetBitContext set at the start of the syntax element. This is a copy, the callee does not need to preserve it.
lengthLength in bits of the syntax element.
nameString name of the syntax elements.
subscriptsIf the syntax element is an array, a pointer to an array of subscripts into the array.
valueParsed value of the syntax element.

Definition at line 189 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
ctxUser-set trace context.
pbcA PutBitContext set at the end of the syntax element. The user must not modify this, but may inspect it to determine state.
lengthLength in bits of the syntax element.
nameString name of the syntax elements.
subscriptsIf the syntax element is an array, a pointer to an array of subscripts into the array.
valueWritten value of the syntax element.

Definition at line 209 of file cbs.h.

Enumeration Type Documentation

◆ CbsDiscardFlags

Enumerator
DISCARD_FLAG_NONE 
DISCARD_FLAG_KEEP_NON_VCL 

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

Definition at line 501 of file cbs.h.

Function Documentation

◆ ff_cbs_init()

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

◆ ff_cbs_flush()

void ff_cbs_flush ( CodedBitstreamContext ctx)

Reset all internal state in a context.

Definition at line 135 of file cbs.c.

Referenced by av1_decode_flush(), and dts2pts_flush().

◆ ff_cbs_close()

void ff_cbs_close ( CodedBitstreamContext **  ctx)

◆ ff_cbs_read_extradata()

int ff_cbs_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.

Referenced by av1_frame_split_init(), dts2pts_init(), ff_cbs_bsf_generic_init(), filter_units_init(), and trace_headers_init().

◆ ff_cbs_read_extradata_from_codec()

int ff_cbs_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.

◆ ff_cbs_read_packet_side_data()

int ff_cbs_read_packet_side_data ( CodedBitstreamContext ctx,
CodedBitstreamFragment frag,
const AVPacket pkt 
)

Definition at line 311 of file cbs.c.

Referenced by cbs_bsf_update_side_data(), and trace_headers().

◆ ff_cbs_read_packet()

int ff_cbs_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.

Referenced by av1_frame_merge_filter(), av1_frame_split_filter(), av1_receive_frame(), decode_nal_units(), ff_cbs_bsf_generic_filter(), filter_units_filter(), h264_filter(), and trace_headers().

◆ ff_cbs_read()

int ff_cbs_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.

Referenced by av1_parser_parse(), and parse_nal_units().

◆ ff_cbs_write_fragment_data()

int ff_cbs_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 408 of file cbs.c.

Referenced by cbs_bsf_update_side_data(), ff_cbs_write_extradata(), ff_cbs_write_packet(), vaapi_encode_av1_write_obu(), vaapi_encode_h264_write_access_unit(), vaapi_encode_h265_write_access_unit(), vaapi_encode_mjpeg_write_image_header(), and vaapi_encode_mpeg2_write_fragment().

◆ ff_cbs_write_extradata()

int ff_cbs_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 444 of file cbs.c.

Referenced by ff_cbs_bsf_generic_init(), and filter_units_init().

◆ ff_cbs_write_packet()

int ff_cbs_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 473 of file cbs.c.

Referenced by av1_frame_merge_filter(), ff_cbs_bsf_generic_filter(), and filter_units_filter().

◆ ff_cbs_fragment_reset()

void ff_cbs_fragment_reset ( CodedBitstreamFragment frag)

◆ ff_cbs_fragment_free()

void ff_cbs_fragment_free ( CodedBitstreamFragment frag)

◆ ff_cbs_alloc_unit_content()

int ff_cbs_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 922 of file cbs.c.

Referenced by cbs_av1_read_unit(), cbs_h264_read_nal_unit(), cbs_h265_read_nal_unit(), cbs_h266_read_nal_unit(), cbs_jpeg_read_unit(), cbs_mpeg2_read_unit(), cbs_sei_get_unit(), cbs_vp8_read_unit(), and cbs_vp9_read_unit().

◆ ff_cbs_insert_unit_content()

int ff_cbs_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 782 of file cbs.c.

Referenced by av1_frame_merge_filter(), av1_metadata_update_fragment(), cbs_sei_get_unit(), h264_metadata_insert_aud(), h265_metadata_update_fragment(), h266_metadata_update_fragment(), mpeg2_metadata_update_fragment(), vaapi_encode_av1_add_obu(), vaapi_encode_h264_add_nal(), vaapi_encode_h265_add_nal(), vaapi_encode_mjpeg_write_image_header(), and vaapi_encode_mpeg2_add_header().

◆ ff_cbs_append_unit_data()

int ff_cbs_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 849 of file cbs.c.

Referenced by cbs_av1_split_fragment(), cbs_h2645_fragment_add_nals(), cbs_jpeg_split_fragment(), cbs_mpeg2_split_fragment(), cbs_vp8_split_fragment(), and cbs_vp9_split_fragment().

◆ ff_cbs_delete_unit()

void ff_cbs_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 859 of file cbs.c.

Referenced by av1_metadata_update_fragment(), ff_cbs_discard_units(), filter_units_filter(), h264_metadata_update_fragment(), h265_metadata_update_fragment(), and h266_metadata_update_fragment().

◆ ff_cbs_make_unit_refcounted()

int ff_cbs_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 1034 of file cbs.c.

Referenced by cbs_av1_write_obu(), and cbs_h2645_replace_ps().

◆ ff_cbs_make_unit_writable()

int ff_cbs_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 1043 of file cbs.c.

Referenced by h264_redundant_pps_fixup_pps().

◆ ff_cbs_discard_units()

void ff_cbs_discard_units ( CodedBitstreamContext ctx,
CodedBitstreamFragment frag,
enum AVDiscard  skip,
int  flags 
)

Discard units accroding to 'skip'.

Definition at line 1060 of file cbs.c.

Referenced by filter_units_filter().

◆ ff_cbs_trace_read_log()

void ff_cbs_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 507 of file cbs.c.

Referenced by ff_cbs_trace_write_log(), and trace_headers_init().

◆ ff_cbs_trace_write_log()

void ff_cbs_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 565 of file cbs.c.

Referenced by ff_cbs_bsf_generic_init().

Variable Documentation

◆ ff_cbs_all_codec_ids

enum AVCodecID ff_cbs_all_codec_ids[]

Table of all supported codec IDs.

Terminated by AV_CODEC_ID_NONE.

Definition at line 61 of file cbs.c.