FFmpeg  4.4.2
Data Fields
AVPacket Struct Reference

This structure stores compressed data. More...

#include <libavcodec/packet.h>

Data Fields

AVBufferRefbuf
 A reference to the reference-counted buffer where the packet data is stored. More...
 
int64_t pts
 Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will be presented to the user. More...
 
int64_t dts
 Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed. More...
 
uint8_t * data
 
int size
 
int stream_index
 
int flags
 A combination of AV_PKT_FLAG values. More...
 
AVPacketSideDataside_data
 Additional packet data that can be provided by the container. More...
 
int side_data_elems
 
int64_t duration
 Duration of this packet in AVStream->time_base units, 0 if unknown. More...
 
int64_t pos
 byte position in stream, -1 if unknown More...
 

Detailed Description

This structure stores compressed data.

It is typically exported by demuxers and then passed as input to decoders, or received as output from encoders and then passed to muxers.

For video, it should typically contain one compressed frame. For audio it may contain several compressed frames. Encoders are allowed to output empty packets, with no compressed data, containing only side data (e.g. to update some stream parameters at the end of encoding).

The semantics of data ownership depends on the buf field. If it is set, the packet data is dynamically allocated and is valid indefinitely until a call to av_packet_unref() reduces the reference count to 0.

If the buf field is not set av_packet_ref() would make a copy instead of increasing the reference count.

The side data is always allocated with av_malloc(), copied by av_packet_ref() and freed by av_packet_unref().

sizeof(AVPacket) being a part of the public ABI is deprecated. once av_init_packet() is removed, new packets will only be able to be allocated with av_packet_alloc(), and new fields may be added to the end of the struct with a minor bump.

See also
av_packet_alloc
av_packet_ref
av_packet_unref
Examples:
decode_audio.c, decode_video.c, demuxing_decoding.c, encode_audio.c, encode_video.c, filtering_audio.c, filtering_video.c, hw_decode.c, muxing.c, qsvdec.c, remuxing.c, transcode_aac.c, transcoding.c, vaapi_encode.c, and vaapi_transcode.c.

Definition at line 346 of file packet.h.

Field Documentation

AVBufferRef* AVPacket::buf

A reference to the reference-counted buffer where the packet data is stored.

May be NULL, then the packet data is not reference-counted.

Definition at line 352 of file packet.h.

int64_t AVPacket::pts

Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will be presented to the user.

Can be AV_NOPTS_VALUE if it is not stored in the file. pts MUST be larger or equal to dts as presentation cannot happen before decompression, unless one wants to view hex dumps. Some formats misuse the terms dts and pts/cts to mean something different. Such timestamps must be converted to true pts/dts before they are stored in AVPacket.

Examples:
encode_video.c, muxing.c, and remuxing.c.

Definition at line 362 of file packet.h.

Referenced by encode(), log_packet(), and main().

int64_t AVPacket::dts

Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.

Can be AV_NOPTS_VALUE if it is not stored in the file.

Examples:
muxing.c, and remuxing.c.

Definition at line 368 of file packet.h.

Referenced by log_packet(), and main().

uint8_t* AVPacket::data
int AVPacket::size
int AVPacket::stream_index
int AVPacket::flags

A combination of AV_PKT_FLAG values.

Definition at line 375 of file packet.h.

AVPacketSideData* AVPacket::side_data

Additional packet data that can be provided by the container.

Packet can contain several types of side information.

Definition at line 380 of file packet.h.

int AVPacket::side_data_elems

Definition at line 381 of file packet.h.

int64_t AVPacket::duration

Duration of this packet in AVStream->time_base units, 0 if unknown.

Equals next_pts - this_pts in presentation order.

Examples:
muxing.c, and remuxing.c.

Definition at line 387 of file packet.h.

Referenced by log_packet(), and main().

int64_t AVPacket::pos

byte position in stream, -1 if unknown

Examples:
remuxing.c.

Definition at line 389 of file packet.h.

Referenced by main().


The documentation for this struct was generated from the following file: