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Core functions/structures.

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

Data Structures

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


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


enum  AVPacketSideDataType {


void av_init_packet (AVPacket *pkt)
 Initialize optional fields of a packet with default values.
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.
int av_dup_packet (AVPacket *pkt)
int av_copy_packet (AVPacket *dst, AVPacket *src)
 Copy packet, including contents.
int av_copy_packet_side_data (AVPacket *dst, AVPacket *src)
 Copy packet side data.
void av_free_packet (AVPacket *pkt)
 Free a packet.
uint8_tav_packet_new_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int size)
 Allocate new information of a packet.
int av_packet_shrink_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int size)
 Shrink the already allocated side data buffer.
uint8_tav_packet_get_side_data (AVPacket *pkt, enum AVPacketSideDataType type, int *size)
 Get side information from packet.
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_KEY   0x0001

The packet contains a keyframe.


Definition at line 1119 of file avcodec.h.

Referenced by a64multi_encode_frame(), ape_tag_read_field(), asf_parse_packet(), asf_read_picture(), asf_read_pts(), asf_write_packet(), av_read_frame(), avcodec_encode_audio2(), 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(), ea_read_packet(), encode_frame(), encode_picture_lossless(), encode_picture_ls(), ff_flac_parse_picture(), 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(), 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().

#define AV_PKT_FLAG_CORRUPT   0x0002

Enumeration Type Documentation


An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:

u32le param_flags
s32le channel_count
u64le channel_layout
s32le width
s32le height

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

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)

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)

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.


Subtitle event position.

u32le x1
u32le y1
u32le x2
u32le y2

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.


The optional first identifier line of a WebVTT cue.


The optional settings (rendering instructions) that immediately follow the timestamp specifier of a WebVTT cue.

Definition at line 924 of file avcodec.h.


Definition at line 1122 of file avcodec.h.

Function Documentation

void av_init_packet ( AVPacket pkt)
int av_new_packet ( AVPacket pkt,
int  size 

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

sizewanted payload size
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(), asf_parse_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_h263_handle_packet(), ff_raw_read_partial_packet(), ff_rm_retrieve_cache(), ff_spdif_read_packet(), ff_subtitles_queue_insert(), ffm_read_packet(), film_read_packet(), fourxm_read_packet(), g723_1_read_packet(), grab_read_packet(), h264_handle_packet(), iff_read_packet(), ilbc_read_packet(), img_read_packet(), interleave_new_audio_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(), read_packet_gme(), 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().

void av_shrink_packet ( AVPacket pkt,
int  size 
int av_grow_packet ( AVPacket pkt,
int  grow_by 

Increase packet size, correctly zeroing padding.

grow_bynumber of bytes by which to increase the size of the packet

Definition at line 105 of file avpacket.c.

Referenced by append_packet_chunked(), encode_callback(), ff_subtitles_queue_insert(), and wv_read_packet().

int av_packet_from_data ( AVPacket pkt,
uint8_t data,
int  size 

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

pktpacket to be initialized. This function will set the data, size, buf and destruct fields, all others are left untouched.
dataData 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.
sizesize of data in bytes, without the padding. I.e. the full buffer size is assumed to be size + FF_INPUT_BUFFER_PADDING_SIZE.
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().

int av_dup_packet ( AVPacket pkt)
This is a hack - the packet memory allocation stuff is broken. The packet is allocated if it was not really allocated.

Definition at line 233 of file avpacket.c.

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

int av_copy_packet ( AVPacket dst,
AVPacket src 

Copy packet, including contents.

0 on success, negative AVERROR on fail

Definition at line 248 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_copy_packet_side_data ( AVPacket dst,
AVPacket src 

Copy packet side data.

0 on success, negative AVERROR on fail

Definition at line 211 of file avpacket.c.

Referenced by copy_packet_data(), and ff_interleave_add_packet().

void av_free_packet ( AVPacket pkt)

Free a packet.

pktpacket to free
doc/examples/decoding_encoding.c, doc/examples/demuxing.c, doc/examples/filtering_audio.c, and doc/examples/filtering_video.c.

Definition at line 254 of file avpacket.c.

Referenced by adp_read_packet(), adx_read_packet(), aiff_write_trailer(), amr_read_packet(), append_packet_chunked(), asf_parse_packet(), 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(), 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_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(), flush_packet(), fourxm_read_packet(), 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_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(), redspark_read_packet(), rl2_read_packet(), rm_assemble_video_frame(), rm_read_packet(), rpl_read_packet(), rsd_read_packet(), sap_fetch_packet(), search_hi_lo_keyframes(), seek_frame_generic(), seek_subtitle(), storeframe(), 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().

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

Allocate new information of a packet.

typeside information type
sizeside information size
pointer to fresh allocated data or NULL otherwise

Definition at line 276 of file avpacket.c.

Referenced by asf_parse_packet(), av_read_frame(), ff_add_param_change(), 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(), storeframe(), and swf_read_packet().

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

Shrink the already allocated side data buffer.

typeside information type
sizenew side information size
0 on success, < 0 on failure

Definition at line 405 of file avpacket.c.

Referenced by ff_MPV_encode_picture().

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

Get side information from packet.

typedesired side information type
sizepointer for side information size to store (optional)
pointer to data if present or NULL otherwise

Definition at line 301 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(), mkv_write_block(), mkv_write_vtt_blocks(), msrle_decode_frame(), msvideo1_decode_frame(), qtrle_decode_frame(), raw_decode(), rtp_write_packet(), smc_decode_frame(), srt_decode_frame(), srt_write_packet(), and webvtt_write_packet().

int av_packet_merge_side_data ( AVPacket pkt)

Definition at line 318 of file avpacket.c.

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

int av_packet_split_side_data ( AVPacket pkt)