AVPacket

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

Collaboration diagram for AVPacket:

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

Macros
#define	AV_PKT_FLAG_KEY   0x0001
	The packet contains a keyframe. More...
#define	AV_PKT_FLAG_CORRUPT   0x0002
	The packet content is corrupted. More...

Typedefs
typedef struct AVPacket	AVPacket
	This structure stores compressed data. More...

Enumerations
enum	AVPacketSideDataType {   AV_PKT_DATA_PALETTE, AV_PKT_DATA_NEW_EXTRADATA, AV_PKT_DATA_PARAM_CHANGE, AV_PKT_DATA_H263_MB_INFO,   AV_PKT_DATA_SKIP_SAMPLES =70, AV_PKT_DATA_JP_DUALMONO, AV_PKT_DATA_STRINGS_METADATA, AV_PKT_DATA_SUBTITLE_POSITION,   AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL }
enum	AVSideDataParamChangeFlags { AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT = 0x0001, AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT = 0x0002, AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE = 0x0004, AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS = 0x0008 }

Functions
void	av_init_packet (AVPacket *pkt)
	Initialize optional fields of a packet with default values. More...
int	av_new_packet (AVPacket *pkt, int size)
	Allocate the payload of a packet and initialize its fields with default values. More...
void	av_shrink_packet (AVPacket *pkt, int size)
	Reduce packet size, correctly zeroing padding. More...
int	av_grow_packet (AVPacket *pkt, int grow_by)
	Increase packet size, correctly zeroing padding. More...
int	av_packet_from_data (AVPacket *pkt, uint8_t *data, int size)
	Initialize a reference-counted packet from av_malloc()ed data. More...
int	av_dup_packet (AVPacket *pkt)
int	av_copy_packet (AVPacket *dst, AVPacket *src)
	Copy packet, including contents. More...
void	av_free_packet (AVPacket *pkt)
	Free a packet. More...
uint8_t *	av_packet_new_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int size)
	Allocate new information of a packet. More...
int	av_packet_shrink_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int size)
	Shrink the already allocated side data buffer. More...
uint8_t *	av_packet_get_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int *size)
	Get side information from packet. More...
int	av_packet_merge_side_data (AVPacket *pkt)
int	av_packet_split_side_data (AVPacket *pkt)

Detailed Description

Types and functions for working with AVPacket.

Macro Definition Documentation

#define AV_PKT_FLAG_CORRUPT   0x0002

The packet content is corrupted.

Definition at line 1102 of file libavcodec/avcodec.h.

Referenced by aiff_read_packet(), apc_read_packet(), append_packet_chunked(), ff_pcm_read_packet(), ff_read_packet(), handle_packet(), mp3_read_packet(), new_pes_packet(), read_packet(), sol_read_packet(), vorbis_packet(), and vp8_handle_packet().

#define AV_PKT_FLAG_KEY   0x0001

The packet contains a keyframe.

Definition at line 1101 of file libavcodec/avcodec.h.

Referenced by a64multi_encode_frame(), ape_tag_read_field(), asf_read_picture(), asf_read_pts(), asf_write_packet(), av_read_frame(), avcodec_encode_audio(), avcodec_encode_audio2(), avcodec_encode_video(), avi_read_packet(), avi_write_packet(), avpriv_dv_produce_packet(), avs_read_audio_packet(), avs_read_video_packet(), avui_encode_frame(), bmp_encode_frame(), cdxl_read_packet(), compute_pkt_fields(), dc1394_read_common(), decode_frame(), dirac_gptopts(), dnxhd_encode_picture(), do_streamcopy(), do_video_out(), dv_extract_audio_info(), dv_write_pack(), ea_read_packet(), encode_frame(), encode_picture_lossless(), encode_picture_ls(), ff_asf_parse_packet(), ff_id3v2_parse_apic(), ff_mov_add_hinted_packet(), ff_mov_write_packet(), ff_MPV_encode_picture(), ff_rm_parse_packet(), ff_rm_retrieve_cache(), ff_subtitles_queue_insert(), ffm_read_packet(), ffm_write_packet(), flashsv2_encode_frame(), flashsv_decode_frame(), flashsv_encode_frame(), flv_data_packet(), flv_read_packet(), flv_write_packet(), framecrc_write_packet(), get_attachment(), get_needed_flags(), gif_encode_frame(), gif_read_packet(), h263_handle_packet(), hls_read_packet(), hls_write_packet(), http_prepare_data(), idcin_read_packet(), iff_read_packet(), img_read_packet(), ism_write_packet(), libopenjpeg_encode_frame(), libschroedinger_encode_frame(), lmlm4_read_packet(), lvf_read_packet(), lxf_read_packet(), main(), matroska_parse_block(), mkv_write_packet(), mkv_write_packet_internal(), modplug_read_packet(), mov_create_chapter_track(), mov_create_timecode_track(), mov_parse_vc1_frame(), mov_read_covr(), mov_read_packet(), mov_write_single_packet(), mpeg_mux_write_packet(), mpegts_write_flush(), mpegts_write_packet_internal(), msnwc_tcp_read_packet(), mv_read_packet(), nsv_read_chunk(), nut_read_packet(), nut_write_packet(), nuv_packet(), ogg_read_packet(), ogg_read_timestamp(), ogg_validate_keyframe(), ogg_write_packet(), ogm_packet(), old_dirac_gptopts(), pam_encode_frame(), parse_packet(), parse_picture(), pcx_encode_frame(), pkt_dump_internal(), pnm_encode_frame(), prores_encode_frame(), put_payload_header(), qt_rtp_parse_packet(), qtrle_encode_frame(), raw_encode(), read_frame(), read_frame_internal(), read_packet(), rm_write_audio(), rm_write_video(), roq_encode_frame(), rpl_read_packet(), search_hi_lo_keyframes(), seek_frame_generic(), seg_write_packet(), show_packet(), siff_read_packet(), smush_read_packet(), Stagefright_decode_frame(), storeframe(), sunrast_encode_frame(), svq1_encode_frame(), targa_encode_frame(), theora_gptopts(), tmv_read_packet(), utvideo_encode_frame(), v308_encode_frame(), v408_encode_frame(), v410_encode_frame(), vc1t_read_packet(), vc1test_write_packet(), vid_read_packet(), write_frame(), write_timestamp(), write_video_frame(), X264_frame(), XAVS_frame(), xbm_encode_frame(), xface_encode_frame(), xmv_fetch_video_packet(), xvid_encode_frame(), xwd_encode_frame(), y41p_encode_frame(), yop_read_packet(), yuv4_encode_frame(), and zerocodec_decode_frame().

Typedef Documentation

typedef struct AVPacket AVPacket

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.

AVPacket is one of the few structs in FFmpeg, whose size is a part of public ABI. Thus it may be allocated on stack and no new fields can be added to it without libavcodec and libavformat major bump.

The semantics of data ownership depends on the buf or destruct (deprecated) fields. If either is set, the packet data is dynamically allocated and is valid indefinitely until av_free_packet() is called (which in turn calls av_buffer_unref()/the destruct callback to free the data). If neither is set, the packet data is typically backed by some static buffer somewhere and is only valid for a limited time (e.g. until the next read call when demuxing).

The side data is always allocated with av_malloc() and is freed in av_free_packet().

Enumeration Type Documentation

enum AVPacketSideDataType

Enumerator
AV_PKT_DATA_PALETTE
AV_PKT_DATA_NEW_EXTRADATA
AV_PKT_DATA_PARAM_CHANGE	An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows: u32le param_flags if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT) s32le channel_count if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT) u64le channel_layout if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE) s32le sample_rate if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS) s32le width s32le height
AV_PKT_DATA_H263_MB_INFO	An AV_PKT_DATA_H263_MB_INFO side data packet contains a number of structures with info about macroblocks relevant to splitting the packet into smaller packets on macroblock edges (e.g. as for RFC 2190). That is, it does not necessarily contain info about all macroblocks, as long as the distance between macroblocks in the info is smaller than the target payload size. Each MB info structure is 12 bytes, and is laid out as follows: u32le bit offset from the start of the packet u8 current quantizer at the start of the macroblock u8 GOB number u16le macroblock address within the GOB u8 horizontal MV predictor u8 vertical MV predictor u8 horizontal MV predictor for block number 3 u8 vertical MV predictor for block number 3
AV_PKT_DATA_SKIP_SAMPLES	Recommmends skipping the specified number of samples. u32le number of samples to skip from start of this packet u32le number of samples to skip from end of this packet u8 reason for start skip u8 reason for end skip (0=padding silence, 1=convergence)
AV_PKT_DATA_JP_DUALMONO	An AV_PKT_DATA_JP_DUALMONO side data packet indicates that the packet may contain "dual mono" audio specific to Japanese DTV and if it is true, recommends only the selected channel to be used. u8 selected channels (0=mail/left, 1=sub/right, 2=both)
AV_PKT_DATA_STRINGS_METADATA	A list of zero terminated key/value strings. There is no end marker for the list, so it is required to rely on the side data size to stop.
AV_PKT_DATA_SUBTITLE_POSITION	Subtitle event position. u32le x1 u32le y1 u32le x2 u32le y2
AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL	Data found in BlockAdditional element of matroska container. There is no end marker for the data, so it is required to rely on the side data size to recognize the end. 8 byte id (as found in BlockAddId) followed by data.

Definition at line 917 of file libavcodec/avcodec.h.

enum AVSideDataParamChangeFlags

Enumerator
AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT
AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT
AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE
AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS

Definition at line 1104 of file libavcodec/avcodec.h.

Function Documentation

int av_copy_packet	(	AVPacket *	dst,
		AVPacket *	src
	)

Copy packet, including contents.

Returns

0 on success, negative AVERROR on fail

Definition at line 236 of file avpacket.c.

Referenced by aiff_write_packet(), ff_subtitles_queue_read_packet(), flush_packet(), gif_write_packet(), read_thread(), tee_write_packet(), and write_packet().

int av_dup_packet

(

AVPacket *

pkt

)

Warning

This is a hack - the packet memory allocation stuff is broken. The packet is allocated if it was not really allocated.

Definition at line 221 of file avpacket.c.

Referenced by av_read_frame(), avcodec_encode_audio2(), avcodec_encode_video2(), avformat_find_stream_info(), ff_interleave_add_packet(), input_thread(), packet_queue_put(), parse_packet(), tee_write_packet(), and worker().

void av_free_packet

(

AVPacket *

pkt

)

Free a packet.

Parameters

pkt	packet to free

Definition at line 242 of file avpacket.c.

Referenced by adx_read_packet(), aiff_write_trailer(), amr_read_packet(), append_packet_chunked(), asf_read_header(), asf_read_picture(), asf_read_pts(), asf_reset_header(), asfrtp_parse_packet(), audio_decode_frame(), audio_encode_example(), audio_read_packet(), av_interleaved_write_frame(), av_packet_merge_side_data(), av_write_trailer(), avcodec_decode_subtitle2(), avcodec_encode_audio2(), avcodec_encode_video2(), avi_read_close(), avi_read_packet(), avs_read_video_packet(), cdxl_read_packet(), cin_read_packet(), dfa_read_packet(), do_audio_out(), do_video_out(), dxa_read_packet(), ea_read_packet(), encode_frame(), estimate_timings_from_pts(), extract_mpeg4_header(), ff_asf_parse_packet(), ff_free_stream(), ff_raw_read_partial_packet(), ff_read_packet(), ff_rm_free_rmstream(), ff_spdif_read_packet(), ff_subtitles_queue_clean(), ffm_read_packet(), flic_read_packet(), flush_packet(), fourxm_read_packet(), free_input_threads(), free_packet_buffer(), free_packet_list(), free_pkt_fifo(), free_variant_list(), g723_1_read_packet(), gsm_read_packet(), hls_read_seek(), http_prepare_data(), idcin_read_packet(), ilbc_read_packet(), img_read_packet(), interleave_packet(), load_ipmovie_packet(), lxf_read_packet(), main(), matroska_clear_queue(), matroska_decode_buffer(), matroska_parse_frame(), mkv_write_packet(), mkv_write_trailer(), mmap_read_frame(), modplug_read_packet(), mov_write_subtitle_end_packet(), movie_push_frame(), mp3_queue_flush(), mpc_read_packet(), mpc_read_seek(), mpegts_get_dts(), mpegts_raw_read_packet(), mpegts_read_packet(), mxf_interleave_get_packet(), nc_read_packet(), nsv_read_close(), nuv_packet(), packet_queue_flush(), packet_queue_put(), parse_packet(), process_input(), pulse_read_packet(), qt_rtp_parse_packet(), read_frame_internal(), read_packet(), read_packets(), read_thread(), recode_subtitle(), rl2_read_packet(), rm_assemble_video_frame(), rm_read_packet(), rpl_read_packet(), sap_fetch_packet(), search_hi_lo_keyframes(), seek_frame_generic(), seek_subtitle(), str_read_close(), str_read_packet(), stream_component_close(), subtitle_thread(), thp_read_packet(), video_encode_example(), video_thread(), vivo_read_packet(), vmd_read_packet(), vqf_read_packet(), wc3_read_close(), write_frame(), write_trailer(), wv_read_packet(), wv_read_seek(), xiph_handle_packet(), xvid_encode_frame(), yop_read_close(), yop_read_packet(), and yop_read_seek().

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

Definition at line 105 of file avpacket.c.

Referenced by append_packet_chunked(), ff_subtitles_queue_insert(), and matroska_decode_buffer().

void av_init_packet

(

AVPacket *

pkt

)

Initialize optional fields of a packet with default values.

Note, this does not touch the data and size members, which have to be initialized separately.

Parameters

pkt

packet

Definition at line 56 of file avpacket.c.

Referenced by audio_decode_example(), audio_encode_example(), av_get_packet(), av_new_packet(), avcodec_encode_audio(), avcodec_encode_audio2(), avcodec_encode_video(), avcodec_encode_video2(), avformat_find_stream_info(), avi_write_packet(), avpriv_dv_produce_packet(), dc1394_read_common(), do_audio_out(), do_streamcopy(), do_subtitle_out(), do_video_out(), dv_extract_audio_info(), encode_frame(), ff_alloc_packet2(), ff_id3v2_parse_apic(), ff_interleave_packet_per_dts(), ff_mov_add_hinted_packet(), ff_read_packet(), ff_rtp_finalize_packet(), flush_encoders(), main(), mkv_write_header(), mov_write_subtitle_end_packet(), movie_push_frame(), mpegts_get_dts(), mpegts_write_packet_internal(), mxf_interleave_get_packet(), new_pes_packet(), output_packet(), parse_packet(), parse_picture(), qt_rtp_parse_packet(), read_frame_internal(), read_packets(), read_thread(), reset_packet(), sp5x_decode_frame(), v4l2_read_packet(), video_decode_example(), video_encode_example(), wc3_read_header(), worker(), write_audio_frame(), write_video_frame(), and x11grab_read_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

Definition at line 73 of file avpacket.c.

Referenced by aac_parse_packet(), amr_handle_packet(), amr_read_packet(), ape_read_packet(), audio_read_packet(), av_grow_packet(), avs_read_video_packet(), bmv_read_packet(), callback(), cdxl_read_packet(), cin_read_packet(), decode_frame(), dxa_read_packet(), fbdev_read_packet(), ff_alloc_packet2(), ff_asf_parse_packet(), ff_h263_handle_packet(), ff_interleave_new_audio_packet(), ff_raw_read_partial_packet(), ff_rm_retrieve_cache(), ff_spdif_read_packet(), ff_subtitles_queue_insert(), ffm_read_packet(), film_read_packet(), flic_read_packet(), fourxm_read_packet(), g723_1_read_packet(), grab_read_packet(), h264_handle_packet(), iff_read_packet(), ilbc_read_packet(), img_read_packet(), latm_parse_packet(), lavfi_read_packet(), load_ipmovie_packet(), lxf_read_packet(), matroska_parse_frame(), matroska_parse_rm_audio(), mmap_read_frame(), modplug_read_packet(), mpc_read_packet(), mpeg_parse_packet(), mpegts_raw_read_packet(), nut_read_packet(), nuv_packet(), ogg_read_packet(), pulse_read_packet(), qdm2_restore_block(), qt_rtp_parse_packet(), read_frame(), read_packet(), recode_subtitle(), return_stored_frame(), rm_assemble_video_frame(), rm_read_audio_stream_info(), roq_read_packet(), rtp_parse_packet_internal(), sbg_read_packet(), seq_read_packet(), siff_read_packet(), smacker_read_packet(), store_packet(), str_read_packet(), supply_new_packets(), swf_read_packet(), videostream_cb(), vmd_read_packet(), vqf_read_packet(), wsaud_read_packet(), wv_read_packet(), xiph_handle_packet(), and yop_read_packet().

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, buf and destruct 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 + FF_INPUT_BUFFER_PADDING_SIZE.

Returns

0 on success, a negative AVERROR on error

Definition at line 136 of file avpacket.c.

Referenced by ff_rtp_finalize_packet(), and qt_rtp_parse_packet().

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

Get side information from packet.

Parameters

pkt	packet
type	desired side information type
size	pointer for side information size to store (optional)

Returns

pointer to data if present or NULL otherwise

Definition at line 289 of file avpacket.c.

Referenced by aac_decode_frame(), aac_decode_frame_int(), add_metadata_from_side_data(), apply_param_change(), avcodec_decode_audio4(), cinepak_decode_frame(), decode_frame(), decode_tag(), flush_packet(), idcin_decode_frame(), ipvideo_decode_frame(), msrle_decode_frame(), msvideo1_decode_frame(), qtrle_decode_frame(), raw_decode(), rtp_write_packet(), smc_decode_frame(), srt_decode_frame(), and srt_write_packet().

int av_packet_merge_side_data

(

AVPacket *

pkt

)

Definition at line 306 of file avpacket.c.

Referenced by avcodec_encode_video2(), ff_read_packet(), and split_write_packet().

uint8_t* av_packet_new_side_data	(	AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		int	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

Definition at line 264 of file avpacket.c.

Referenced by av_read_frame(), avi_read_packet(), ff_add_param_change(), ff_asf_parse_packet(), ff_MPV_encode_picture(), flv_read_packet(), gif_encode_frame(), gif_image_write_image(), idcin_read_packet(), lavfi_read_packet(), load_ipmovie_packet(), matroska_parse_frame(), mov_read_packet(), read_frame(), srt_read_header(), and swf_read_packet().

int av_packet_shrink_side_data	(	AVPacket *	pkt,
		enum AVPacketSideDataType	type,
		int	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

Definition at line 386 of file avpacket.c.

Referenced by ff_MPV_encode_picture().

int av_packet_split_side_data

(

AVPacket *

pkt

)

Definition at line 344 of file avpacket.c.

Referenced by avcodec_decode_audio4(), avcodec_decode_subtitle2(), avcodec_decode_video2(), and split_write_packet().

void av_shrink_packet	(	AVPacket *	pkt,
		int	size
	)

Reduce packet size, correctly zeroing padding.

Parameters

pkt	packet
size	new size

Definition at line 97 of file avpacket.c.

Referenced by append_packet_chunked(), cdxl_read_packet(), cin_read_packet(), ff_asf_parse_packet(), ff_raw_read_partial_packet(), libopus_encode(), mxf_decrypt_triplet(), mxf_get_d10_aes3_packet(), nuv_packet(), and yop_read_packet().