AVPacket

Types and functions for working with AVPacket. More...

Data Structures
struct	AVPacket
	This structure stores compressed data. More...

Macros
#define	AV_PKT_FLAG_KEY   0x0001
	The packet contains a keyframe.
#define	AV_PKT_FLAG_CORRUPT   0x0002
	The packet content is corrupted.
#define	AV_PKT_FLAG_DISCARD   0x0004
	Flag is used to discard packets which are required to maintain valid decoder state but are not required for output and should be dropped after decoding.
#define	AV_PKT_FLAG_TRUSTED   0x0008
	The packet comes from a trusted source.
#define	AV_PKT_FLAG_DISPOSABLE   0x0010
	Flag is used to indicate packets that contain frames that can be discarded by the decoder.

Enumerations
enum	AVSideDataParamChangeFlags { AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE = 0x0004 , AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS = 0x0008 }

Functions
AVPacket *	av_packet_alloc (void)
	Allocate an AVPacket and set its fields to default values.
AVPacket *	av_packet_clone (const AVPacket *src)
	Create a new packet that references the same data as src.
void	av_packet_free (AVPacket **pkt)
	Free the packet, if the packet is reference counted, it will be unreferenced first.
int	av_new_packet (AVPacket *pkt, int size)
	Allocate the payload of a packet and initialize its fields with default values.
void	av_shrink_packet (AVPacket *pkt, int size)
	Reduce packet size, correctly zeroing padding.
int	av_grow_packet (AVPacket *pkt, int grow_by)
	Increase packet size, correctly zeroing padding.
int	av_packet_from_data (AVPacket *pkt, uint8_t *data, int size)
	Initialize a reference-counted packet from av_malloc()ed data.
uint8_t *	av_packet_new_side_data (AVPacket *pkt, enum AVPacketSideDataType type, size_t size)
	Allocate new information of a packet.
int	av_packet_add_side_data (AVPacket *pkt, enum AVPacketSideDataType type, uint8_t *data, size_t size)
	Wrap an existing array as a packet side data.
int	av_packet_shrink_side_data (AVPacket *pkt, enum AVPacketSideDataType type, size_t size)
	Shrink the already allocated side data buffer.
uint8_t *	av_packet_get_side_data (const AVPacket *pkt, enum AVPacketSideDataType type, size_t *size)
	Get side information from packet.
uint8_t *	av_packet_pack_dictionary (AVDictionary *dict, size_t *size)
	Pack a dictionary for use in side_data.
int	av_packet_unpack_dictionary (const uint8_t *data, size_t size, AVDictionary **dict)
	Unpack a dictionary from side_data.
void	av_packet_free_side_data (AVPacket *pkt)
	Convenience function to free all the side data stored.
int	av_packet_ref (AVPacket *dst, const AVPacket *src)
	Setup a new reference to the data described by a given packet.
void	av_packet_unref (AVPacket *pkt)
	Wipe the packet.
void	av_packet_move_ref (AVPacket *dst, AVPacket *src)
	Move every field in src to dst and reset src.
int	av_packet_copy_props (AVPacket *dst, const AVPacket *src)
	Copy only "properties" fields from src to dst.
int	av_packet_make_refcounted (AVPacket *pkt)
	Ensure the data described by a given packet is reference counted.
int	av_packet_make_writable (AVPacket *pkt)
	Create a writable reference for the data described by a given packet, avoiding data copy if possible.
void	av_packet_rescale_ts (AVPacket *pkt, AVRational tb_src, AVRational tb_dst)
	Convert valid timing fields (timestamps / durations) in a packet from one timebase to another.

Detailed Description

Types and functions for working with AVPacket.

Macro Definition Documentation

AV_PKT_FLAG_KEY

#define AV_PKT_FLAG_KEY   0x0001

The packet contains a keyframe.

Definition at line 594 of file packet.h.

AV_PKT_FLAG_CORRUPT

#define AV_PKT_FLAG_CORRUPT   0x0002

The packet content is corrupted.

Definition at line 595 of file packet.h.

AV_PKT_FLAG_DISCARD

#define AV_PKT_FLAG_DISCARD   0x0004

Flag is used to discard packets which are required to maintain valid decoder state but are not required for output and should be dropped after decoding.

Definition at line 601 of file packet.h.

AV_PKT_FLAG_TRUSTED

#define AV_PKT_FLAG_TRUSTED   0x0008

The packet comes from a trusted source.

Otherwise-unsafe constructs such as arbitrary pointers to data outside the packet may be followed.

Definition at line 608 of file packet.h.

AV_PKT_FLAG_DISPOSABLE

#define AV_PKT_FLAG_DISPOSABLE   0x0010

Flag is used to indicate packets that contain frames that can be discarded by the decoder.

I.e. Non-reference frames.

Definition at line 613 of file packet.h.

Enumeration Type Documentation

AVSideDataParamChangeFlags

enum AVSideDataParamChangeFlags

Enumerator
AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE
AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS

Definition at line 615 of file packet.h.

Function Documentation

av_packet_alloc()

AVPacket * av_packet_alloc

(

void

)

Allocate an AVPacket and set its fields to default values.

The resulting struct must be freed using av_packet_free().

Returns

An AVPacket filled with default values or NULL on failure.

Note

this only allocates the AVPacket itself, not the data buffers. Those must be allocated through other means such as av_new_packet.

See also

av_new_packet

Examples

decode_audio.c, decode_filter_audio.c, decode_filter_video.c, decode_video.c, demux_decode.c, encode_audio.c, encode_video.c, extract_mvs.c, hw_decode.c, mux.c, qsv_decode.c, qsv_transcode.c, remux.c, transcode.c, transcode_aac.c, vaapi_encode.c, and vaapi_transcode.c.

Referenced by add_stream(), encode_write(), init_filters(), init_packet(), main(), and main().

av_packet_clone()

AVPacket * av_packet_clone

(

const AVPacket *

src

)

Create a new packet that references the same data as src.

This is a shortcut for av_packet_alloc()+av_packet_ref().

Returns

newly created AVPacket on success, NULL on error.

See also

av_packet_alloc

av_packet_ref

av_packet_free()

void av_packet_free

(

AVPacket **

pkt

)

Free the packet, if the packet is reference counted, it will be unreferenced first.

Parameters

pkt	packet to be freed. The pointer will be set to NULL.

Note

passing NULL is a no-op.

Examples

decode_audio.c, decode_filter_audio.c, decode_filter_video.c, decode_video.c, demux_decode.c, encode_audio.c, encode_video.c, extract_mvs.c, hw_decode.c, mux.c, qsv_decode.c, qsv_transcode.c, remux.c, transcode.c, transcode_aac.c, vaapi_encode.c, and vaapi_transcode.c.

Referenced by close_stream(), decode_audio_frame(), encode_audio_frame(), encode_write(), main(), and main().

av_new_packet()

int av_new_packet	(	AVPacket *	pkt,
		int	size
	)

Allocate the payload of a packet and initialize its fields with default values.

Parameters

pkt	packet
size	wanted payload size

Returns

0 if OK, AVERROR_xxx otherwise

av_shrink_packet()

void av_shrink_packet	(	AVPacket *	pkt,
		int	size
	)

Reduce packet size, correctly zeroing padding.

Parameters

pkt	packet
size	new size

av_grow_packet()

int av_grow_packet	(	AVPacket *	pkt,
		int	grow_by
	)

Increase packet size, correctly zeroing padding.

Parameters

pkt	packet
grow_by	number of bytes by which to increase the size of the packet

av_packet_from_data()

int av_packet_from_data	(	AVPacket *	pkt,
		uint8_t *	data,
		int	size
	)

Initialize a reference-counted packet from av_malloc()ed data.

Parameters

pkt	packet to be initialized. This function will set the data, size, and buf fields, all others are left untouched.
data	Data allocated by av_malloc() to be used as packet data. If this function returns successfully, the data is owned by the underlying AVBuffer. The caller may not access the data through other means.
size	size of data in bytes, without the padding. I.e. the full buffer size is assumed to be size + AV_INPUT_BUFFER_PADDING_SIZE.

Returns

0 on success, a negative AVERROR on error

av_packet_new_side_data()

uint8_t * av_packet_new_side_data	(	AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		size_t	size
	)

Allocate new information of a packet.

Parameters

pkt	packet
type	side information type
size	side information size

Returns

pointer to fresh allocated data or NULL otherwise

av_packet_add_side_data()

int av_packet_add_side_data	(	AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		uint8_t *	data,
		size_t	size
	)

Wrap an existing array as a packet side data.

Parameters

pkt	packet
type	side information type
data	the side data array. It must be allocated with the av_malloc() family of functions. The ownership of the data is transferred to pkt.
size	side information size

Returns

a non-negative number on success, a negative AVERROR code on failure. On failure, the packet is unchanged and the data remains owned by the caller.

av_packet_shrink_side_data()

int av_packet_shrink_side_data	(	AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		size_t	size
	)

Shrink the already allocated side data buffer.

Parameters

pkt	packet
type	side information type
size	new side information size

Returns

0 on success, < 0 on failure

av_packet_get_side_data()

uint8_t * av_packet_get_side_data	(	const AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		size_t *	size
	)

Get side information from packet.

Parameters

pkt	packet
type	desired side information type
size	If supplied, *size will be set to the size of the side data or to zero if the desired side data is not present.

Returns

pointer to data if present or NULL otherwise

av_packet_pack_dictionary()

uint8_t * av_packet_pack_dictionary	(	AVDictionary *	dict,
		size_t *	size
	)

Pack a dictionary for use in side_data.

Parameters

dict	The dictionary to pack.
size	pointer to store the size of the returned data

Returns

pointer to data if successful, NULL otherwise

av_packet_unpack_dictionary()

int av_packet_unpack_dictionary	(	const uint8_t *	data,
		size_t	size,
		AVDictionary **	dict
	)

Unpack a dictionary from side_data.

Parameters

data	data from side_data
size	size of the data
dict	the metadata storage dictionary

Returns

0 on success, < 0 on failure

av_packet_free_side_data()

void av_packet_free_side_data

(

AVPacket *

pkt

)

Convenience function to free all the side data stored.

All the other fields stay untouched.

Parameters

pkt

packet

av_packet_ref()

int av_packet_ref	(	AVPacket *	dst,
		const AVPacket *	src
	)

Setup a new reference to the data described by a given packet.

If src is reference-counted, setup dst as a new reference to the buffer in src. Otherwise allocate a new buffer in dst and copy the data from src into it.

All the other fields are copied from src.

See also

av_packet_unref

Parameters

dst	Destination packet. Will be completely overwritten.
src	Source packet

Returns

0 on success, a negative AVERROR on error. On error, dst will be blank (as if returned by av_packet_alloc()).

av_packet_unref()

void av_packet_unref

(

AVPacket *

pkt

)

Wipe the packet.

Unreference the buffer referenced by the packet and reset the remaining packet fields to their default values.

Parameters

pkt	The packet to be unreferenced.

Examples

decode_filter_audio.c, decode_filter_video.c, demux_decode.c, encode_audio.c, encode_video.c, extract_mvs.c, hw_decode.c, qsv_decode.c, qsv_transcode.c, remux.c, transcode.c, vaapi_encode.c, and vaapi_transcode.c.

Referenced by encode(), encode(), encode_write(), encode_write(), encode_write(), encode_write_frame(), main(), and main().

av_packet_move_ref()

void av_packet_move_ref	(	AVPacket *	dst,
		AVPacket *	src
	)

Move every field in src to dst and reset src.

See also

av_packet_unref

Parameters

src	Source packet, will be reset
dst	Destination packet

av_packet_copy_props()

int av_packet_copy_props	(	AVPacket *	dst,
		const AVPacket *	src
	)

Copy only "properties" fields from src to dst.

Properties for the purpose of this function are all the fields beside those related to the packet data (buf, data, size)

Parameters

dst	Destination packet
src	Source packet

Returns

0 on success AVERROR on failure.

av_packet_make_refcounted()

int av_packet_make_refcounted

(

AVPacket *

pkt

)

Ensure the data described by a given packet is reference counted.

Note

This function does not ensure that the reference will be writable. Use av_packet_make_writable instead for that purpose.

See also

av_packet_ref

av_packet_make_writable

Parameters

pkt	packet whose data should be made reference counted.

Returns

0 on success, a negative AVERROR on error. On failure, the packet is unchanged.

av_packet_make_writable()

int av_packet_make_writable

(

AVPacket *

pkt

)

Create a writable reference for the data described by a given packet, avoiding data copy if possible.

Parameters

pkt	Packet whose data should be made writable.

Returns

0 on success, a negative AVERROR on failure. On failure, the packet is unchanged.

av_packet_rescale_ts()

void av_packet_rescale_ts	(	AVPacket *	pkt,
		AVRational	tb_src,
		AVRational	tb_dst
	)

Convert valid timing fields (timestamps / durations) in a packet from one timebase to another.

Timestamps with unknown values (AV_NOPTS_VALUE) will be ignored.

Parameters

pkt	packet on which the conversion will be performed
tb_src	source timebase, in which the timing fields in pkt are expressed
tb_dst	destination timebase, to which the timing fields will be converted

Examples

mux.c, qsv_transcode.c, remux.c, transcode.c, and vaapi_transcode.c.

Referenced by encode_write(), encode_write(), encode_write_frame(), main(), and write_frame().