2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #ifndef AVCODEC_AVCODEC_H
22 #define AVCODEC_AVCODEC_H
25 * @file libavcodec/avcodec.h
30 #include "libavutil/avutil.h"
32 #define LIBAVCODEC_VERSION_MAJOR 52
33 #define LIBAVCODEC_VERSION_MINOR 54
34 #define LIBAVCODEC_VERSION_MICRO 0
36 #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
37 LIBAVCODEC_VERSION_MINOR, \
38 LIBAVCODEC_VERSION_MICRO)
39 #define LIBAVCODEC_VERSION AV_VERSION(LIBAVCODEC_VERSION_MAJOR, \
40 LIBAVCODEC_VERSION_MINOR, \
41 LIBAVCODEC_VERSION_MICRO)
42 #define LIBAVCODEC_BUILD LIBAVCODEC_VERSION_INT
44 #define LIBAVCODEC_IDENT "Lavc" AV_STRINGIFY(LIBAVCODEC_VERSION)
46 #define AV_NOPTS_VALUE INT64_C(0x8000000000000000)
47 #define AV_TIME_BASE 1000000
48 #define AV_TIME_BASE_Q (AVRational){1, AV_TIME_BASE}
51 * Identifies the syntax and semantics of the bitstream.
52 * The principle is roughly:
53 * Two decoders with the same ID can decode the same streams.
54 * Two encoders with the same ID can encode compatible streams.
55 * There may be slight deviations from the principle due to implementation
58 * If you add a codec ID to this list, add it so that
59 * 1. no value of a existing codec ID changes (that would break ABI),
60 * 2. it is as close as possible to similar codecs.
67 CODEC_ID_MPEG2VIDEO, ///< preferred ID for MPEG-1/2 video decoding
68 CODEC_ID_MPEG2VIDEO_XVMC,
105 CODEC_ID_INTERPLAY_VIDEO,
117 CODEC_ID_TRUEMOTION1,
145 CODEC_ID_TRUEMOTION2,
162 CODEC_ID_DSICINVIDEO,
163 CODEC_ID_TIERTEXSEQVIDEO,
172 CODEC_ID_BETHSOFTVID,
190 CODEC_ID_MOTIONPIXELS,
208 CODEC_ID_IFF_BYTERUN1,
210 /* various PCM "codecs" */
211 CODEC_ID_PCM_S16LE= 0x10000,
227 CODEC_ID_PCM_S24DAUD,
229 CODEC_ID_PCM_S16LE_PLANAR,
237 /* various ADPCM codecs */
238 CODEC_ID_ADPCM_IMA_QT= 0x11000,
239 CODEC_ID_ADPCM_IMA_WAV,
240 CODEC_ID_ADPCM_IMA_DK3,
241 CODEC_ID_ADPCM_IMA_DK4,
242 CODEC_ID_ADPCM_IMA_WS,
243 CODEC_ID_ADPCM_IMA_SMJPEG,
252 CODEC_ID_ADPCM_YAMAHA,
253 CODEC_ID_ADPCM_SBPRO_4,
254 CODEC_ID_ADPCM_SBPRO_3,
255 CODEC_ID_ADPCM_SBPRO_2,
257 CODEC_ID_ADPCM_IMA_AMV,
258 CODEC_ID_ADPCM_EA_R1,
259 CODEC_ID_ADPCM_EA_R3,
260 CODEC_ID_ADPCM_EA_R2,
261 CODEC_ID_ADPCM_IMA_EA_SEAD,
262 CODEC_ID_ADPCM_IMA_EA_EACS,
263 CODEC_ID_ADPCM_EA_XAS,
264 CODEC_ID_ADPCM_EA_MAXIS_XA,
265 CODEC_ID_ADPCM_IMA_ISS,
268 CODEC_ID_AMR_NB= 0x12000,
271 /* RealAudio codecs*/
272 CODEC_ID_RA_144= 0x13000,
275 /* various DPCM codecs */
276 CODEC_ID_ROQ_DPCM= 0x14000,
277 CODEC_ID_INTERPLAY_DPCM,
282 CODEC_ID_MP2= 0x15000,
283 CODEC_ID_MP3, ///< preferred ID for decoding MPEG audio layer 1, 2 or 3
301 CODEC_ID_WESTWOOD_SND1,
302 CODEC_ID_GSM, ///< as in Berlin toast format
310 CODEC_ID_DSICINAUDIO,
314 CODEC_ID_GSM_MS, /* as found in WAV */
323 CODEC_ID_WMALOSSLESS,
332 CODEC_ID_BINKAUDIO_RDFT,
333 CODEC_ID_BINKAUDIO_DCT,
335 /* subtitle codecs */
336 CODEC_ID_DVD_SUBTITLE= 0x17000,
337 CODEC_ID_DVB_SUBTITLE,
338 CODEC_ID_TEXT, ///< raw UTF-8 text
342 CODEC_ID_HDMV_PGS_SUBTITLE,
343 CODEC_ID_DVB_TELETEXT,
345 /* other specific kind of codecs (generally used for attachments) */
346 CODEC_ID_TTF= 0x18000,
348 CODEC_ID_PROBE= 0x19000, ///< codec_id is not known (like CODEC_ID_NONE) but lavf should attempt to identify it
350 CODEC_ID_MPEG2TS= 0x20000, /**< _FAKE_ codec to indicate a raw MPEG-2 TS
351 * stream (only used by libavformat) */
355 CODEC_TYPE_UNKNOWN = -1,
360 CODEC_TYPE_ATTACHMENT,
365 * all in native-endian format
368 SAMPLE_FMT_NONE = -1,
369 SAMPLE_FMT_U8, ///< unsigned 8 bits
370 SAMPLE_FMT_S16, ///< signed 16 bits
371 SAMPLE_FMT_S32, ///< signed 32 bits
372 SAMPLE_FMT_FLT, ///< float
373 SAMPLE_FMT_DBL, ///< double
374 SAMPLE_FMT_NB ///< Number of sample formats. DO NOT USE if dynamically linking to libavcodec
377 /* Audio channel masks */
378 #define CH_FRONT_LEFT 0x00000001
379 #define CH_FRONT_RIGHT 0x00000002
380 #define CH_FRONT_CENTER 0x00000004
381 #define CH_LOW_FREQUENCY 0x00000008
382 #define CH_BACK_LEFT 0x00000010
383 #define CH_BACK_RIGHT 0x00000020
384 #define CH_FRONT_LEFT_OF_CENTER 0x00000040
385 #define CH_FRONT_RIGHT_OF_CENTER 0x00000080
386 #define CH_BACK_CENTER 0x00000100
387 #define CH_SIDE_LEFT 0x00000200
388 #define CH_SIDE_RIGHT 0x00000400
389 #define CH_TOP_CENTER 0x00000800
390 #define CH_TOP_FRONT_LEFT 0x00001000
391 #define CH_TOP_FRONT_CENTER 0x00002000
392 #define CH_TOP_FRONT_RIGHT 0x00004000
393 #define CH_TOP_BACK_LEFT 0x00008000
394 #define CH_TOP_BACK_CENTER 0x00010000
395 #define CH_TOP_BACK_RIGHT 0x00020000
396 #define CH_STEREO_LEFT 0x20000000 ///< Stereo downmix.
397 #define CH_STEREO_RIGHT 0x40000000 ///< See CH_STEREO_LEFT.
399 /** Channel mask value used for AVCodecContext.request_channel_layout
400 to indicate that the user requests the channel order of the decoder output
401 to be the native codec channel order. */
402 #define CH_LAYOUT_NATIVE 0x8000000000000000LL
404 /* Audio channel convenience macros */
405 #define CH_LAYOUT_MONO (CH_FRONT_CENTER)
406 #define CH_LAYOUT_STEREO (CH_FRONT_LEFT|CH_FRONT_RIGHT)
407 #define CH_LAYOUT_2_1 (CH_LAYOUT_STEREO|CH_BACK_CENTER)
408 #define CH_LAYOUT_SURROUND (CH_LAYOUT_STEREO|CH_FRONT_CENTER)
409 #define CH_LAYOUT_4POINT0 (CH_LAYOUT_SURROUND|CH_BACK_CENTER)
410 #define CH_LAYOUT_2_2 (CH_LAYOUT_STEREO|CH_SIDE_LEFT|CH_SIDE_RIGHT)
411 #define CH_LAYOUT_QUAD (CH_LAYOUT_STEREO|CH_BACK_LEFT|CH_BACK_RIGHT)
412 #define CH_LAYOUT_5POINT0 (CH_LAYOUT_SURROUND|CH_SIDE_LEFT|CH_SIDE_RIGHT)
413 #define CH_LAYOUT_5POINT1 (CH_LAYOUT_5POINT0|CH_LOW_FREQUENCY)
414 #define CH_LAYOUT_5POINT0_BACK (CH_LAYOUT_SURROUND|CH_BACK_LEFT|CH_BACK_RIGHT)
415 #define CH_LAYOUT_5POINT1_BACK (CH_LAYOUT_5POINT0_BACK|CH_LOW_FREQUENCY)
416 #define CH_LAYOUT_7POINT0 (CH_LAYOUT_5POINT0|CH_BACK_LEFT|CH_BACK_RIGHT)
417 #define CH_LAYOUT_7POINT1 (CH_LAYOUT_5POINT1|CH_BACK_LEFT|CH_BACK_RIGHT)
418 #define CH_LAYOUT_7POINT1_WIDE (CH_LAYOUT_5POINT1_BACK|\
419 CH_FRONT_LEFT_OF_CENTER|CH_FRONT_RIGHT_OF_CENTER)
420 #define CH_LAYOUT_STEREO_DOWNMIX (CH_STEREO_LEFT|CH_STEREO_RIGHT)
423 #define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio
426 * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
427 * This is mainly needed because some optimized bitstream readers read
428 * 32 or 64 bit at once and could read over the end.<br>
429 * Note: If the first 23 bits of the additional bytes are not 0, then damaged
430 * MPEG bitstreams could cause overread and segfault.
432 #define FF_INPUT_BUFFER_PADDING_SIZE 8
435 * minimum encoding buffer size
436 * Used to avoid some checks during header writing.
438 #define FF_MIN_BUFFER_SIZE 16384
442 * motion estimation type.
445 ME_ZERO = 1, ///< no search, that is use 0,0 vector whenever one is needed
449 ME_EPZS, ///< enhanced predictive zonal search
450 ME_X1, ///< reserved for experiments
451 ME_HEX, ///< hexagon based search
452 ME_UMH, ///< uneven multi-hexagon search
453 ME_ITER, ///< iterative search
454 ME_TESA, ///< transformed exhaustive search algorithm
458 /* We leave some space between them for extensions (drop some
459 * keyframes for intra-only or drop just some bidir frames). */
460 AVDISCARD_NONE =-16, ///< discard nothing
461 AVDISCARD_DEFAULT= 0, ///< discard useless packets like 0 size packets in avi
462 AVDISCARD_NONREF = 8, ///< discard all non reference
463 AVDISCARD_BIDIR = 16, ///< discard all bidirectional frames
464 AVDISCARD_NONKEY = 32, ///< discard all frames except keyframes
465 AVDISCARD_ALL = 48, ///< discard all
468 enum AVColorPrimaries{
469 AVCOL_PRI_BT709 =1, ///< also ITU-R BT1361 / IEC 61966-2-4 / SMPTE RP177 Annex B
470 AVCOL_PRI_UNSPECIFIED=2,
472 AVCOL_PRI_BT470BG =5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM
473 AVCOL_PRI_SMPTE170M =6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC
474 AVCOL_PRI_SMPTE240M =7, ///< functionally identical to above
476 AVCOL_PRI_NB , ///< Not part of ABI
479 enum AVColorTransferCharacteristic{
480 AVCOL_TRC_BT709 =1, ///< also ITU-R BT1361
481 AVCOL_TRC_UNSPECIFIED=2,
482 AVCOL_TRC_GAMMA22 =4, ///< also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM
483 AVCOL_TRC_GAMMA28 =5, ///< also ITU-R BT470BG
484 AVCOL_TRC_NB , ///< Not part of ABI
489 AVCOL_SPC_BT709 =1, ///< also ITU-R BT1361 / IEC 61966-2-4 xvYCC709 / SMPTE RP177 Annex B
490 AVCOL_SPC_UNSPECIFIED=2,
492 AVCOL_SPC_BT470BG =5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM / IEC 61966-2-4 xvYCC601
493 AVCOL_SPC_SMPTE170M =6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC / functionally identical to above
494 AVCOL_SPC_SMPTE240M =7,
495 AVCOL_SPC_NB , ///< Not part of ABI
499 AVCOL_RANGE_UNSPECIFIED=0,
500 AVCOL_RANGE_MPEG =1, ///< the normal 219*2^(n-8) "MPEG" YUV ranges
501 AVCOL_RANGE_JPEG =2, ///< the normal 2^n-1 "JPEG" YUV ranges
502 AVCOL_RANGE_NB , ///< Not part of ABI
506 * X X 3 4 X X are luma samples,
507 * 1 2 1-6 are possible chroma positions
508 * X X 5 6 X 0 is undefined/unknown position
510 enum AVChromaLocation{
511 AVCHROMA_LOC_UNSPECIFIED=0,
512 AVCHROMA_LOC_LEFT =1, ///< mpeg2/4, h264 default
513 AVCHROMA_LOC_CENTER =2, ///< mpeg1, jpeg, h263
514 AVCHROMA_LOC_TOPLEFT =3, ///< DV
516 AVCHROMA_LOC_BOTTOMLEFT =5,
517 AVCHROMA_LOC_BOTTOM =6,
518 AVCHROMA_LOC_NB , ///< Not part of ABI
521 typedef struct RcOverride{
524 int qscale; // If this is 0 then quality_factor will be used instead.
525 float quality_factor;
528 #define FF_MAX_B_FRAMES 16
531 These flags can be passed in AVCodecContext.flags before initialization.
532 Note: Not everything is supported yet.
535 #define CODEC_FLAG_QSCALE 0x0002 ///< Use fixed qscale.
536 #define CODEC_FLAG_4MV 0x0004 ///< 4 MV per MB allowed / advanced prediction for H.263.
537 #define CODEC_FLAG_QPEL 0x0010 ///< Use qpel MC.
538 #define CODEC_FLAG_GMC 0x0020 ///< Use GMC.
539 #define CODEC_FLAG_MV0 0x0040 ///< Always try a MB with MV=<0,0>.
540 #define CODEC_FLAG_PART 0x0080 ///< Use data partitioning.
542 * The parent program guarantees that the input for B-frames containing
543 * streams is not written to for at least s->max_b_frames+1 frames, if
544 * this is not set the input will be copied.
546 #define CODEC_FLAG_INPUT_PRESERVED 0x0100
547 #define CODEC_FLAG_PASS1 0x0200 ///< Use internal 2pass ratecontrol in first pass mode.
548 #define CODEC_FLAG_PASS2 0x0400 ///< Use internal 2pass ratecontrol in second pass mode.
549 #define CODEC_FLAG_EXTERN_HUFF 0x1000 ///< Use external Huffman table (for MJPEG).
550 #define CODEC_FLAG_GRAY 0x2000 ///< Only decode/encode grayscale.
551 #define CODEC_FLAG_EMU_EDGE 0x4000 ///< Don't draw edges.
552 #define CODEC_FLAG_PSNR 0x8000 ///< error[?] variables will be set during encoding.
553 #define CODEC_FLAG_TRUNCATED 0x00010000 /** Input bitstream might be truncated at a random
554 location instead of only at frame boundaries. */
555 #define CODEC_FLAG_NORMALIZE_AQP 0x00020000 ///< Normalize adaptive quantization.
556 #define CODEC_FLAG_INTERLACED_DCT 0x00040000 ///< Use interlaced DCT.
557 #define CODEC_FLAG_LOW_DELAY 0x00080000 ///< Force low delay.
558 #define CODEC_FLAG_ALT_SCAN 0x00100000 ///< Use alternate scan.
559 #define CODEC_FLAG_GLOBAL_HEADER 0x00400000 ///< Place global headers in extradata instead of every keyframe.
560 #define CODEC_FLAG_BITEXACT 0x00800000 ///< Use only bitexact stuff (except (I)DCT).
561 /* Fx : Flag for h263+ extra options */
562 #define CODEC_FLAG_AC_PRED 0x01000000 ///< H.263 advanced intra coding / MPEG-4 AC prediction
563 #define CODEC_FLAG_H263P_UMV 0x02000000 ///< unlimited motion vector
564 #define CODEC_FLAG_CBP_RD 0x04000000 ///< Use rate distortion optimization for cbp.
565 #define CODEC_FLAG_QP_RD 0x08000000 ///< Use rate distortion optimization for qp selectioon.
566 #define CODEC_FLAG_H263P_AIV 0x00000008 ///< H.263 alternative inter VLC
567 #define CODEC_FLAG_OBMC 0x00000001 ///< OBMC
568 #define CODEC_FLAG_LOOP_FILTER 0x00000800 ///< loop filter
569 #define CODEC_FLAG_H263P_SLICE_STRUCT 0x10000000
570 #define CODEC_FLAG_INTERLACED_ME 0x20000000 ///< interlaced motion estimation
571 #define CODEC_FLAG_SVCD_SCAN_OFFSET 0x40000000 ///< Will reserve space for SVCD scan offset user data.
572 #define CODEC_FLAG_CLOSED_GOP 0x80000000
573 #define CODEC_FLAG2_FAST 0x00000001 ///< Allow non spec compliant speedup tricks.
574 #define CODEC_FLAG2_STRICT_GOP 0x00000002 ///< Strictly enforce GOP size.
575 #define CODEC_FLAG2_NO_OUTPUT 0x00000004 ///< Skip bitstream encoding.
576 #define CODEC_FLAG2_LOCAL_HEADER 0x00000008 ///< Place global headers at every keyframe instead of in extradata.
577 #define CODEC_FLAG2_BPYRAMID 0x00000010 ///< H.264 allow B-frames to be used as references.
578 #define CODEC_FLAG2_WPRED 0x00000020 ///< H.264 weighted biprediction for B-frames
579 #define CODEC_FLAG2_MIXED_REFS 0x00000040 ///< H.264 one reference per partition, as opposed to one reference per macroblock
580 #define CODEC_FLAG2_8X8DCT 0x00000080 ///< H.264 high profile 8x8 transform
581 #define CODEC_FLAG2_FASTPSKIP 0x00000100 ///< H.264 fast pskip
582 #define CODEC_FLAG2_AUD 0x00000200 ///< H.264 access unit delimiters
583 #define CODEC_FLAG2_BRDO 0x00000400 ///< B-frame rate-distortion optimization
584 #define CODEC_FLAG2_INTRA_VLC 0x00000800 ///< Use MPEG-2 intra VLC table.
585 #define CODEC_FLAG2_MEMC_ONLY 0x00001000 ///< Only do ME/MC (I frames -> ref, P frame -> ME+MC).
586 #define CODEC_FLAG2_DROP_FRAME_TIMECODE 0x00002000 ///< timecode is in drop frame format.
587 #define CODEC_FLAG2_SKIP_RD 0x00004000 ///< RD optimal MB level residual skipping
588 #define CODEC_FLAG2_CHUNKS 0x00008000 ///< Input bitstream might be truncated at a packet boundaries instead of only at frame boundaries.
589 #define CODEC_FLAG2_NON_LINEAR_QUANT 0x00010000 ///< Use MPEG-2 nonlinear quantizer.
590 #define CODEC_FLAG2_BIT_RESERVOIR 0x00020000 ///< Use a bit reservoir when encoding if possible
591 #define CODEC_FLAG2_MBTREE 0x00040000 ///< Use macroblock tree ratecontrol (x264 only)
593 /* Unsupported options :
594 * Syntax Arithmetic coding (SAC)
595 * Reference Picture Selection
596 * Independent Segment Decoding */
598 /* codec capabilities */
600 #define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 ///< Decoder can use draw_horiz_band callback.
602 * Codec uses get_buffer() for allocating buffers.
603 * direct rendering method 1
605 #define CODEC_CAP_DR1 0x0002
606 /* If 'parse_only' field is true, then avcodec_parse_frame() can be used. */
607 #define CODEC_CAP_PARSE_ONLY 0x0004
608 #define CODEC_CAP_TRUNCATED 0x0008
609 /* Codec can export data for HW decoding (XvMC). */
610 #define CODEC_CAP_HWACCEL 0x0010
612 * Codec has a nonzero delay and needs to be fed with NULL at the end to get the delayed data.
613 * If this is not set, the codec is guaranteed to never be fed with NULL data.
615 #define CODEC_CAP_DELAY 0x0020
617 * Codec can be fed a final frame with a smaller size.
618 * This can be used to prevent truncation of the last audio samples.
620 #define CODEC_CAP_SMALL_LAST_FRAME 0x0040
622 * Codec can export data for HW decoding (VDPAU).
624 #define CODEC_CAP_HWACCEL_VDPAU 0x0080
626 * Codec can output multiple frames per AVPacket
627 * Normally demuxers return one frame at a time, demuxers which do not do
628 * are connected to a parser to split what they return into proper frames.
629 * This flag is reserved to the very rare category of codecs which have a
630 * bitstream that cannot be split into frames without timeconsuming
631 * operations like full decoding. Demuxers carring such bitstreams thus
632 * may return multiple frames in a packet. This has many disadvantages like
633 * prohibiting stream copy in many cases thus it should only be considered
636 #define CODEC_CAP_SUBFRAMES 0x0100
638 //The following defines may change, don't expect compatibility if you use them.
639 #define MB_TYPE_INTRA4x4 0x0001
640 #define MB_TYPE_INTRA16x16 0x0002 //FIXME H.264-specific
641 #define MB_TYPE_INTRA_PCM 0x0004 //FIXME H.264-specific
642 #define MB_TYPE_16x16 0x0008
643 #define MB_TYPE_16x8 0x0010
644 #define MB_TYPE_8x16 0x0020
645 #define MB_TYPE_8x8 0x0040
646 #define MB_TYPE_INTERLACED 0x0080
647 #define MB_TYPE_DIRECT2 0x0100 //FIXME
648 #define MB_TYPE_ACPRED 0x0200
649 #define MB_TYPE_GMC 0x0400
650 #define MB_TYPE_SKIP 0x0800
651 #define MB_TYPE_P0L0 0x1000
652 #define MB_TYPE_P1L0 0x2000
653 #define MB_TYPE_P0L1 0x4000
654 #define MB_TYPE_P1L1 0x8000
655 #define MB_TYPE_L0 (MB_TYPE_P0L0 | MB_TYPE_P1L0)
656 #define MB_TYPE_L1 (MB_TYPE_P0L1 | MB_TYPE_P1L1)
657 #define MB_TYPE_L0L1 (MB_TYPE_L0 | MB_TYPE_L1)
658 #define MB_TYPE_QUANT 0x00010000
659 #define MB_TYPE_CBP 0x00020000
660 //Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)
664 * This specifies the area which should be displayed.
665 * Note there may be multiple such areas for one frame.
667 typedef struct AVPanScan{
670 * - encoding: Set by user.
671 * - decoding: Set by libavcodec.
676 * width and height in 1/16 pel
677 * - encoding: Set by user.
678 * - decoding: Set by libavcodec.
684 * position of the top left corner in 1/16 pel for up to 3 fields/frames
685 * - encoding: Set by user.
686 * - decoding: Set by libavcodec.
688 int16_t position[3][2];
691 #define FF_COMMON_FRAME \
693 * pointer to the picture planes.\
694 * This might be different from the first allocated byte\
701 * pointer to the first allocated byte of the picture. Can be used in get_buffer/release_buffer.\
702 * This isn't used by libavcodec unless the default get/release_buffer() is used.\
708 * 1 -> keyframe, 0-> not\
709 * - encoding: Set by libavcodec.\
710 * - decoding: Set by libavcodec.\
715 * Picture type of the frame, see ?_TYPE below.\
716 * - encoding: Set by libavcodec. for coded_picture (and set by user for input).\
717 * - decoding: Set by libavcodec.\
722 * presentation timestamp in time_base units (time when frame should be shown to user)\
723 * If AV_NOPTS_VALUE then frame_rate = 1/time_base will be assumed.\
724 * - encoding: MUST be set by user.\
725 * - decoding: Set by libavcodec.\
730 * picture number in bitstream order\
731 * - encoding: set by\
732 * - decoding: Set by libavcodec.\
734 int coded_picture_number;\
736 * picture number in display order\
737 * - encoding: set by\
738 * - decoding: Set by libavcodec.\
740 int display_picture_number;\
743 * quality (between 1 (good) and FF_LAMBDA_MAX (bad)) \
744 * - encoding: Set by libavcodec. for coded_picture (and set by user for input).\
745 * - decoding: Set by libavcodec.\
750 * buffer age (1->was last buffer and dint change, 2->..., ...).\
751 * Set to INT_MAX if the buffer has not been used yet.\
752 * - encoding: unused\
753 * - decoding: MUST be set by get_buffer().\
758 * is this picture used as reference\
759 * The values for this are the same as the MpegEncContext.picture_structure\
760 * variable, that is 1->top field, 2->bottom field, 3->frame/both fields.\
761 * Set to 4 for delayed, non-reference frames.\
762 * - encoding: unused\
763 * - decoding: Set by libavcodec. (before get_buffer() call)).\
769 * - encoding: unused\
770 * - decoding: Set by libavcodec.\
772 int8_t *qscale_table;\
775 * - encoding: unused\
776 * - decoding: Set by libavcodec.\
781 * mbskip_table[mb]>=1 if MB didn't change\
782 * stride= mb_width = (width+15)>>4\
783 * - encoding: unused\
784 * - decoding: Set by libavcodec.\
786 uint8_t *mbskip_table;\
789 * motion vector table\
792 * int mv_sample_log2= 4 - motion_subsample_log2;\
793 * int mb_width= (width+15)>>4;\
794 * int mv_stride= (mb_width << mv_sample_log2) + 1;\
795 * motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];\
797 * - encoding: Set by user.\
798 * - decoding: Set by libavcodec.\
800 int16_t (*motion_val[2])[2];\
803 * macroblock type table\
804 * mb_type_base + mb_width + 2\
805 * - encoding: Set by user.\
806 * - decoding: Set by libavcodec.\
811 * log2 of the size of the block which a single vector in motion_val represents: \
812 * (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)\
813 * - encoding: unused\
814 * - decoding: Set by libavcodec.\
816 uint8_t motion_subsample_log2;\
819 * for some private data of the user\
820 * - encoding: unused\
821 * - decoding: Set by user.\
827 * - encoding: Set by libavcodec. if flags&CODEC_FLAG_PSNR.\
828 * - decoding: unused\
833 * type of the buffer (to keep track of who has to deallocate data[*])\
834 * - encoding: Set by the one who allocates it.\
835 * - decoding: Set by the one who allocates it.\
836 * Note: User allocated (direct rendering) & internal buffers cannot coexist currently.\
841 * When decoding, this signals how much the picture must be delayed.\
842 * extra_delay = repeat_pict / (2*fps)\
843 * - encoding: unused\
844 * - decoding: Set by libavcodec.\
854 * The content of the picture is interlaced.\
855 * - encoding: Set by user.\
856 * - decoding: Set by libavcodec. (default 0)\
858 int interlaced_frame;\
861 * If the content is interlaced, is top field displayed first.\
862 * - encoding: Set by user.\
863 * - decoding: Set by libavcodec.\
865 int top_field_first;\
869 * - encoding: Set by user.\
870 * - decoding: Set by libavcodec.\
872 AVPanScan *pan_scan;\
875 * Tell user application that palette has changed from previous frame.\
876 * - encoding: ??? (no palette-enabled encoder yet)\
877 * - decoding: Set by libavcodec. (default 0).\
879 int palette_has_changed;\
882 * codec suggestion on buffer type if != 0\
883 * - encoding: unused\
884 * - decoding: Set by libavcodec. (before get_buffer() call)).\
890 * - encoding: unused\
891 * - decoding: Set by libavcodec.\
896 * motion referece frame index\
897 * - encoding: Set by user.\
898 * - decoding: Set by libavcodec.\
900 int8_t *ref_index[2];\
903 * reordered opaque 64bit number (generally a PTS) from AVCodecContext.reordered_opaque\
904 * output in AVFrame.reordered_opaque\
905 * - encoding: unused\
906 * - decoding: Read by user.\
908 int64_t reordered_opaque;\
911 * hardware accelerator private data (FFmpeg allocated)\
912 * - encoding: unused\
913 * - decoding: Set by libavcodec\
915 void *hwaccel_picture_private;\
918 #define FF_QSCALE_TYPE_MPEG1 0
919 #define FF_QSCALE_TYPE_MPEG2 1
920 #define FF_QSCALE_TYPE_H264 2
921 #define FF_QSCALE_TYPE_VP56 3
923 #define FF_BUFFER_TYPE_INTERNAL 1
924 #define FF_BUFFER_TYPE_USER 2 ///< direct rendering buffers (image is (de)allocated by user)
925 #define FF_BUFFER_TYPE_SHARED 4 ///< Buffer from somewhere else; don't deallocate image (data/base), all other tables are not shared.
926 #define FF_BUFFER_TYPE_COPY 8 ///< Just a (modified) copy of some other buffer, don't deallocate anything.
929 #define FF_I_TYPE 1 ///< Intra
930 #define FF_P_TYPE 2 ///< Predicted
931 #define FF_B_TYPE 3 ///< Bi-dir predicted
932 #define FF_S_TYPE 4 ///< S(GMC)-VOP MPEG4
933 #define FF_SI_TYPE 5 ///< Switching Intra
934 #define FF_SP_TYPE 6 ///< Switching Predicted
937 #define FF_BUFFER_HINTS_VALID 0x01 // Buffer hints value is meaningful (if 0 ignore).
938 #define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer.
939 #define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content.
940 #define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update).
942 typedef struct AVPacket {
944 * Presentation timestamp in AVStream->time_base units; the time at which
945 * the decompressed packet will be presented to the user.
946 * Can be AV_NOPTS_VALUE if it is not stored in the file.
947 * pts MUST be larger or equal to dts as presentation cannot happen before
948 * decompression, unless one wants to view hex dumps. Some formats misuse
949 * the terms dts and pts/cts to mean something different. Such timestamps
950 * must be converted to true pts/dts before they are stored in AVPacket.
954 * Decompression timestamp in AVStream->time_base units; the time at which
955 * the packet is decompressed.
956 * Can be AV_NOPTS_VALUE if it is not stored in the file.
964 * Duration of this packet in AVStream->time_base units, 0 if unknown.
965 * Equals next_pts - this_pts in presentation order.
968 void (*destruct)(struct AVPacket *);
970 int64_t pos; ///< byte position in stream, -1 if unknown
973 * Time difference in AVStream->time_base units from the pts of this
974 * packet to the point at which the output from the decoder has converged
975 * independent from the availability of previous frames. That is, the
976 * frames are virtually identical no matter if decoding started from
977 * the very first frame or from this keyframe.
978 * Is AV_NOPTS_VALUE if unknown.
979 * This field is not the display duration of the current packet.
981 * The purpose of this field is to allow seeking in streams that have no
982 * keyframes in the conventional sense. It corresponds to the
983 * recovery point SEI in H.264 and match_time_delta in NUT. It is also
984 * essential for some types of subtitle streams to ensure that all
985 * subtitles are correctly displayed after seeking.
987 int64_t convergence_duration;
989 #define AV_PKT_FLAG_KEY 0x0001
990 #if LIBAVCODEC_VERSION_MAJOR < 53
991 #define PKT_FLAG_KEY AV_PKT_FLAG_KEY
996 * New fields can be added to the end of FF_COMMON_FRAME with minor version
998 * Removal, reordering and changes to existing fields require a major
999 * version bump. No fields should be added into AVFrame before or after
1001 * sizeof(AVFrame) must not be used outside libav*.
1003 typedef struct AVFrame {
1008 * main external API structure.
1009 * New fields can be added to the end with minor version bumps.
1010 * Removal, reordering and changes to existing fields require a major
1012 * sizeof(AVCodecContext) must not be used outside libav*.
1014 typedef struct AVCodecContext {
1016 * information on struct for av_log
1017 * - set by avcodec_alloc_context
1019 const AVClass *av_class;
1021 * the average bitrate
1022 * - encoding: Set by user; unused for constant quantizer encoding.
1023 * - decoding: Set by libavcodec. 0 or some bitrate if this info is available in the stream.
1028 * number of bits the bitstream is allowed to diverge from the reference.
1029 * the reference can be CBR (for CBR pass1) or VBR (for pass2)
1030 * - encoding: Set by user; unused for constant quantizer encoding.
1031 * - decoding: unused
1033 int bit_rate_tolerance;
1037 * - encoding: Set by user.
1038 * - decoding: Set by user.
1043 * Some codecs need additional format info. It is stored here.
1044 * If any muxer uses this then ALL demuxers/parsers AND encoders for the
1045 * specific codec MUST set it correctly otherwise stream copy breaks.
1046 * In general use of this field by muxers is not recommanded.
1047 * - encoding: Set by libavcodec.
1048 * - decoding: Set by libavcodec. (FIXME: Is this OK?)
1053 * Motion estimation algorithm used for video coding.
1054 * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
1055 * 8 (umh), 9 (iter), 10 (tesa) [7, 8, 10 are x264 specific, 9 is snow specific]
1056 * - encoding: MUST be set by user.
1057 * - decoding: unused
1062 * some codecs need / can use extradata like Huffman tables.
1063 * mjpeg: Huffman tables
1064 * rv10: additional flags
1065 * mpeg4: global headers (they can be in the bitstream or here)
1066 * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
1067 * than extradata_size to avoid prolems if it is read with the bitstream reader.
1068 * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
1069 * - encoding: Set/allocated/freed by libavcodec.
1070 * - decoding: Set/allocated/freed by user.
1076 * This is the fundamental unit of time (in seconds) in terms
1077 * of which frame timestamps are represented. For fixed-fps content,
1078 * timebase should be 1/framerate and timestamp increments should be
1080 * - encoding: MUST be set by user.
1081 * - decoding: Set by libavcodec.
1083 AVRational time_base;
1087 * picture width / height.
1088 * - encoding: MUST be set by user.
1089 * - decoding: Set by libavcodec.
1090 * Note: For compatibility it is possible to set this instead of
1091 * coded_width/height before decoding.
1095 #define FF_ASPECT_EXTENDED 15
1098 * the number of pictures in a group of pictures, or 0 for intra_only
1099 * - encoding: Set by user.
1100 * - decoding: unused
1105 * Pixel format, see PIX_FMT_xxx.
1106 * - encoding: Set by user.
1107 * - decoding: Set by libavcodec.
1109 enum PixelFormat pix_fmt;
1112 * Frame rate emulation. If not zero, the lower layer (i.e. format handler)
1113 * has to read frames at native frame rate.
1114 * - encoding: Set by user.
1115 * - decoding: unused
1120 * If non NULL, 'draw_horiz_band' is called by the libavcodec
1121 * decoder to draw a horizontal band. It improves cache usage. Not
1122 * all codecs can do that. You must check the codec capabilities
1124 * The function is also used by hardware acceleration APIs.
1125 * It is called at least once during frame decoding to pass
1126 * the data needed for hardware render.
1127 * In that mode instead of pixel data, AVFrame points to
1128 * a structure specific to the acceleration API. The application
1129 * reads the structure and can change some fields to indicate progress
1131 * - encoding: unused
1132 * - decoding: Set by user.
1133 * @param height the height of the slice
1134 * @param y the y position of the slice
1135 * @param type 1->top field, 2->bottom field, 3->frame
1136 * @param offset offset into the AVFrame.data from which the slice should be read
1138 void (*draw_horiz_band)(struct AVCodecContext *s,
1139 const AVFrame *src, int offset[4],
1140 int y, int type, int height);
1143 int sample_rate; ///< samples per second
1144 int channels; ///< number of audio channels
1147 * audio sample format
1148 * - encoding: Set by user.
1149 * - decoding: Set by libavcodec.
1151 enum SampleFormat sample_fmt; ///< sample format
1153 /* The following data should not be initialized. */
1155 * Samples per packet, initialized when calling 'init'.
1158 int frame_number; ///< audio or video frame number
1159 #if LIBAVCODEC_VERSION_MAJOR < 53
1160 int real_pict_num; ///< Returns the real picture number of previous encoded frame.
1164 * Number of frames the decoded output will be delayed relative to
1165 * the encoded input.
1166 * - encoding: Set by libavcodec.
1167 * - decoding: unused
1171 /* - encoding parameters */
1172 float qcompress; ///< amount of qscale change between easy & hard scenes (0.0-1.0)
1173 float qblur; ///< amount of qscale smoothing over time (0.0-1.0)
1177 * - encoding: Set by user.
1178 * - decoding: unused
1184 * - encoding: Set by user.
1185 * - decoding: unused
1190 * maximum quantizer difference between frames
1191 * - encoding: Set by user.
1192 * - decoding: unused
1197 * maximum number of B-frames between non-B-frames
1198 * Note: The output will be delayed by max_b_frames+1 relative to the input.
1199 * - encoding: Set by user.
1200 * - decoding: unused
1205 * qscale factor between IP and B-frames
1206 * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
1207 * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1208 * - encoding: Set by user.
1209 * - decoding: unused
1211 float b_quant_factor;
1213 /** obsolete FIXME remove */
1215 #define FF_RC_STRATEGY_XVID 1
1217 int b_frame_strategy;
1221 * - encoding: unused
1222 * - decoding: Set by user. 1-> Skip B-frames, 2-> Skip IDCT/dequant too, 5-> Skip everything except header
1223 * @deprecated Deprecated in favor of skip_idct and skip_frame.
1227 struct AVCodec *codec;
1231 int rtp_payload_size; /* The size of the RTP payload: the coder will */
1232 /* do its best to deliver a chunk with size */
1233 /* below rtp_payload_size, the chunk will start */
1234 /* with a start code on some codecs like H.263. */
1235 /* This doesn't take account of any particular */
1236 /* headers inside the transmitted RTP payload. */
1239 /* The RTP callback: This function is called */
1240 /* every time the encoder has a packet to send. */
1241 /* It depends on the encoder if the data starts */
1242 /* with a Start Code (it should). H.263 does. */
1243 /* mb_nb contains the number of macroblocks */
1244 /* encoded in the RTP payload. */
1245 void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb);
1247 /* statistics, used for 2-pass encoding */
1258 * number of bits used for the previously encoded frame
1259 * - encoding: Set by libavcodec.
1260 * - decoding: unused
1265 * Private data of the user, can be used to carry app specific stuff.
1266 * - encoding: Set by user.
1267 * - decoding: Set by user.
1271 char codec_name[32];
1272 enum CodecType codec_type; /* see CODEC_TYPE_xxx */
1273 enum CodecID codec_id; /* see CODEC_ID_xxx */
1276 * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1277 * This is used to work around some encoder bugs.
1278 * A demuxer should set this to what is stored in the field used to identify the codec.
1279 * If there are multiple such fields in a container then the demuxer should choose the one
1280 * which maximizes the information about the used codec.
1281 * If the codec tag field in a container is larger then 32 bits then the demuxer should
1282 * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
1283 * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
1285 * - encoding: Set by user, if not then the default based on codec_id will be used.
1286 * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1288 unsigned int codec_tag;
1291 * Work around bugs in encoders which sometimes cannot be detected automatically.
1292 * - encoding: Set by user
1293 * - decoding: Set by user
1295 int workaround_bugs;
1296 #define FF_BUG_AUTODETECT 1 ///< autodetection
1297 #define FF_BUG_OLD_MSMPEG4 2
1298 #define FF_BUG_XVID_ILACE 4
1299 #define FF_BUG_UMP4 8
1300 #define FF_BUG_NO_PADDING 16
1301 #define FF_BUG_AMV 32
1302 #define FF_BUG_AC_VLC 0 ///< Will be removed, libavcodec can now handle these non-compliant files by default.
1303 #define FF_BUG_QPEL_CHROMA 64
1304 #define FF_BUG_STD_QPEL 128
1305 #define FF_BUG_QPEL_CHROMA2 256
1306 #define FF_BUG_DIRECT_BLOCKSIZE 512
1307 #define FF_BUG_EDGE 1024
1308 #define FF_BUG_HPEL_CHROMA 2048
1309 #define FF_BUG_DC_CLIP 4096
1310 #define FF_BUG_MS 8192 ///< Work around various bugs in Microsoft's broken decoders.
1311 #define FF_BUG_TRUNCATED 16384
1312 //#define FF_BUG_FAKE_SCALABILITY 16 //Autodetection should work 100%.
1315 * luma single coefficient elimination threshold
1316 * - encoding: Set by user.
1317 * - decoding: unused
1319 int luma_elim_threshold;
1322 * chroma single coeff elimination threshold
1323 * - encoding: Set by user.
1324 * - decoding: unused
1326 int chroma_elim_threshold;
1329 * strictly follow the standard (MPEG4, ...).
1330 * - encoding: Set by user.
1331 * - decoding: Set by user.
1332 * Setting this to STRICT or higher means the encoder and decoder will
1333 * generally do stupid things. While setting it to inofficial or lower
1334 * will mean the encoder might use things that are not supported by all
1335 * spec compliant decoders. Decoders make no difference between normal,
1336 * inofficial and experimental, that is they always try to decode things
1337 * when they can unless they are explicitly asked to behave stupid
1338 * (=strictly conform to the specs)
1340 int strict_std_compliance;
1341 #define FF_COMPLIANCE_VERY_STRICT 2 ///< Strictly conform to a older more strict version of the spec or reference software.
1342 #define FF_COMPLIANCE_STRICT 1 ///< Strictly conform to all the things in the spec no matter what consequences.
1343 #define FF_COMPLIANCE_NORMAL 0
1344 #define FF_COMPLIANCE_INOFFICIAL -1 ///< Allow inofficial extensions.
1345 #define FF_COMPLIANCE_EXPERIMENTAL -2 ///< Allow nonstandardized experimental things.
1348 * qscale offset between IP and B-frames
1349 * - encoding: Set by user.
1350 * - decoding: unused
1352 float b_quant_offset;
1355 * Error recognization; higher values will detect more errors but may
1356 * misdetect some more or less valid parts as errors.
1357 * - encoding: unused
1358 * - decoding: Set by user.
1360 int error_recognition;
1361 #define FF_ER_CAREFUL 1
1362 #define FF_ER_COMPLIANT 2
1363 #define FF_ER_AGGRESSIVE 3
1364 #define FF_ER_VERY_AGGRESSIVE 4
1367 * Called at the beginning of each frame to get a buffer for it.
1368 * If pic.reference is set then the frame will be read later by libavcodec.
1369 * avcodec_align_dimensions() should be used to find the required width and
1370 * height, as they normally need to be rounded up to the next multiple of 16.
1371 * if CODEC_CAP_DR1 is not set then get_buffer() must call
1372 * avcodec_default_get_buffer() instead of providing buffers allocated by
1374 * - encoding: unused
1375 * - decoding: Set by libavcodec., user can override.
1377 int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);
1380 * Called to release buffers which were allocated with get_buffer.
1381 * A released buffer can be reused in get_buffer().
1382 * pic.data[*] must be set to NULL.
1383 * - encoding: unused
1384 * - decoding: Set by libavcodec., user can override.
1386 void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);
1389 * Size of the frame reordering buffer in the decoder.
1390 * For MPEG-2 it is 1 IPB or 0 low delay IP.
1391 * - encoding: Set by libavcodec.
1392 * - decoding: Set by libavcodec.
1397 * number of bytes per packet if constant and known or 0
1398 * Used by some WAV based audio codecs.
1402 int parse_only; /* - decoding only: If true, only parsing is done
1403 (function avcodec_parse_frame()). The frame
1404 data is returned. Only MPEG codecs support this now. */
1407 * 0-> h263 quant 1-> mpeg quant
1408 * - encoding: Set by user.
1409 * - decoding: unused
1414 * pass1 encoding statistics output buffer
1415 * - encoding: Set by libavcodec.
1416 * - decoding: unused
1421 * pass2 encoding statistics input buffer
1422 * Concatenated stuff from stats_out of pass1 should be placed here.
1423 * - encoding: Allocated/set/freed by user.
1424 * - decoding: unused
1429 * ratecontrol qmin qmax limiting method
1430 * 0-> clipping, 1-> use a nice continous function to limit qscale wthin qmin/qmax.
1431 * - encoding: Set by user.
1432 * - decoding: unused
1440 * ratecontrol override, see RcOverride
1441 * - encoding: Allocated/set/freed by user.
1442 * - decoding: unused
1444 RcOverride *rc_override;
1445 int rc_override_count;
1448 * rate control equation
1449 * - encoding: Set by user
1450 * - decoding: unused
1456 * - encoding: Set by user.
1457 * - decoding: unused
1463 * - encoding: Set by user.
1464 * - decoding: unused
1469 * decoder bitstream buffer size
1470 * - encoding: Set by user.
1471 * - decoding: unused
1474 float rc_buffer_aggressivity;
1477 * qscale factor between P and I-frames
1478 * If > 0 then the last p frame quantizer will be used (q= lastp_q*factor+offset).
1479 * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1480 * - encoding: Set by user.
1481 * - decoding: unused
1483 float i_quant_factor;
1486 * qscale offset between P and I-frames
1487 * - encoding: Set by user.
1488 * - decoding: unused
1490 float i_quant_offset;
1493 * initial complexity for pass1 ratecontrol
1494 * - encoding: Set by user.
1495 * - decoding: unused
1497 float rc_initial_cplx;
1500 * DCT algorithm, see FF_DCT_* below
1501 * - encoding: Set by user.
1502 * - decoding: unused
1505 #define FF_DCT_AUTO 0
1506 #define FF_DCT_FASTINT 1
1507 #define FF_DCT_INT 2
1508 #define FF_DCT_MMX 3
1509 #define FF_DCT_MLIB 4
1510 #define FF_DCT_ALTIVEC 5
1511 #define FF_DCT_FAAN 6
1514 * luminance masking (0-> disabled)
1515 * - encoding: Set by user.
1516 * - decoding: unused
1521 * temporary complexity masking (0-> disabled)
1522 * - encoding: Set by user.
1523 * - decoding: unused
1525 float temporal_cplx_masking;
1528 * spatial complexity masking (0-> disabled)
1529 * - encoding: Set by user.
1530 * - decoding: unused
1532 float spatial_cplx_masking;
1535 * p block masking (0-> disabled)
1536 * - encoding: Set by user.
1537 * - decoding: unused
1542 * darkness masking (0-> disabled)
1543 * - encoding: Set by user.
1544 * - decoding: unused
1549 * IDCT algorithm, see FF_IDCT_* below.
1550 * - encoding: Set by user.
1551 * - decoding: Set by user.
1554 #define FF_IDCT_AUTO 0
1555 #define FF_IDCT_INT 1
1556 #define FF_IDCT_SIMPLE 2
1557 #define FF_IDCT_SIMPLEMMX 3
1558 #define FF_IDCT_LIBMPEG2MMX 4
1559 #define FF_IDCT_PS2 5
1560 #define FF_IDCT_MLIB 6
1561 #define FF_IDCT_ARM 7
1562 #define FF_IDCT_ALTIVEC 8
1563 #define FF_IDCT_SH4 9
1564 #define FF_IDCT_SIMPLEARM 10
1565 #define FF_IDCT_H264 11
1566 #define FF_IDCT_VP3 12
1567 #define FF_IDCT_IPP 13
1568 #define FF_IDCT_XVIDMMX 14
1569 #define FF_IDCT_CAVS 15
1570 #define FF_IDCT_SIMPLEARMV5TE 16
1571 #define FF_IDCT_SIMPLEARMV6 17
1572 #define FF_IDCT_SIMPLEVIS 18
1573 #define FF_IDCT_WMV2 19
1574 #define FF_IDCT_FAAN 20
1575 #define FF_IDCT_EA 21
1576 #define FF_IDCT_SIMPLENEON 22
1577 #define FF_IDCT_SIMPLEALPHA 23
1581 * - encoding: Set by libavcodec.
1582 * - decoding: Set by user (or 0).
1586 * slice offsets in the frame in bytes
1587 * - encoding: Set/allocated by libavcodec.
1588 * - decoding: Set/allocated by user (or NULL).
1593 * error concealment flags
1594 * - encoding: unused
1595 * - decoding: Set by user.
1597 int error_concealment;
1598 #define FF_EC_GUESS_MVS 1
1599 #define FF_EC_DEBLOCK 2
1602 * dsp_mask could be add used to disable unwanted CPU features
1603 * CPU features (i.e. MMX, SSE. ...)
1605 * With the FORCE flag you may instead enable given CPU features.
1606 * (Dangerous: Usable in case of misdetection, improper usage however will
1607 * result into program crash.)
1610 #define FF_MM_FORCE 0x80000000 /* Force usage of selected flags (OR) */
1611 /* lower 16 bits - CPU features */
1612 #define FF_MM_MMX 0x0001 ///< standard MMX
1613 #define FF_MM_3DNOW 0x0004 ///< AMD 3DNOW
1614 #if LIBAVCODEC_VERSION_MAJOR < 53
1615 #define FF_MM_MMXEXT 0x0002 ///< SSE integer functions or AMD MMX ext
1617 #define FF_MM_MMX2 0x0002 ///< SSE integer functions or AMD MMX ext
1618 #define FF_MM_SSE 0x0008 ///< SSE functions
1619 #define FF_MM_SSE2 0x0010 ///< PIV SSE2 functions
1620 #define FF_MM_3DNOWEXT 0x0020 ///< AMD 3DNowExt
1621 #define FF_MM_SSE3 0x0040 ///< Prescott SSE3 functions
1622 #define FF_MM_SSSE3 0x0080 ///< Conroe SSSE3 functions
1623 #define FF_MM_SSE4 0x0100 ///< Penryn SSE4.1 functions
1624 #define FF_MM_SSE42 0x0200 ///< Nehalem SSE4.2 functions
1625 #define FF_MM_IWMMXT 0x0100 ///< XScale IWMMXT
1626 #define FF_MM_ALTIVEC 0x0001 ///< standard AltiVec
1629 * bits per sample/pixel from the demuxer (needed for huffyuv).
1630 * - encoding: Set by libavcodec.
1631 * - decoding: Set by user.
1633 int bits_per_coded_sample;
1636 * prediction method (needed for huffyuv)
1637 * - encoding: Set by user.
1638 * - decoding: unused
1640 int prediction_method;
1641 #define FF_PRED_LEFT 0
1642 #define FF_PRED_PLANE 1
1643 #define FF_PRED_MEDIAN 2
1646 * sample aspect ratio (0 if unknown)
1647 * That is the width of a pixel divided by the height of the pixel.
1648 * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
1649 * - encoding: Set by user.
1650 * - decoding: Set by libavcodec.
1652 AVRational sample_aspect_ratio;
1655 * the picture in the bitstream
1656 * - encoding: Set by libavcodec.
1657 * - decoding: Set by libavcodec.
1659 AVFrame *coded_frame;
1663 * - encoding: Set by user.
1664 * - decoding: Set by user.
1667 #define FF_DEBUG_PICT_INFO 1
1668 #define FF_DEBUG_RC 2
1669 #define FF_DEBUG_BITSTREAM 4
1670 #define FF_DEBUG_MB_TYPE 8
1671 #define FF_DEBUG_QP 16
1672 #define FF_DEBUG_MV 32
1673 #define FF_DEBUG_DCT_COEFF 0x00000040
1674 #define FF_DEBUG_SKIP 0x00000080
1675 #define FF_DEBUG_STARTCODE 0x00000100
1676 #define FF_DEBUG_PTS 0x00000200
1677 #define FF_DEBUG_ER 0x00000400
1678 #define FF_DEBUG_MMCO 0x00000800
1679 #define FF_DEBUG_BUGS 0x00001000
1680 #define FF_DEBUG_VIS_QP 0x00002000
1681 #define FF_DEBUG_VIS_MB_TYPE 0x00004000
1682 #define FF_DEBUG_BUFFERS 0x00008000
1686 * - encoding: Set by user.
1687 * - decoding: Set by user.
1690 #define FF_DEBUG_VIS_MV_P_FOR 0x00000001 //visualize forward predicted MVs of P frames
1691 #define FF_DEBUG_VIS_MV_B_FOR 0x00000002 //visualize forward predicted MVs of B frames
1692 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
1696 * - encoding: Set by libavcodec if flags&CODEC_FLAG_PSNR.
1697 * - decoding: unused
1702 * minimum MB quantizer
1703 * - encoding: unused
1704 * - decoding: unused
1709 * maximum MB quantizer
1710 * - encoding: unused
1711 * - decoding: unused
1716 * motion estimation comparison function
1717 * - encoding: Set by user.
1718 * - decoding: unused
1722 * subpixel motion estimation comparison function
1723 * - encoding: Set by user.
1724 * - decoding: unused
1728 * macroblock comparison function (not supported yet)
1729 * - encoding: Set by user.
1730 * - decoding: unused
1734 * interlaced DCT comparison function
1735 * - encoding: Set by user.
1736 * - decoding: unused
1739 #define FF_CMP_SAD 0
1740 #define FF_CMP_SSE 1
1741 #define FF_CMP_SATD 2
1742 #define FF_CMP_DCT 3
1743 #define FF_CMP_PSNR 4
1744 #define FF_CMP_BIT 5
1746 #define FF_CMP_ZERO 7
1747 #define FF_CMP_VSAD 8
1748 #define FF_CMP_VSSE 9
1749 #define FF_CMP_NSSE 10
1750 #define FF_CMP_W53 11
1751 #define FF_CMP_W97 12
1752 #define FF_CMP_DCTMAX 13
1753 #define FF_CMP_DCT264 14
1754 #define FF_CMP_CHROMA 256
1757 * ME diamond size & shape
1758 * - encoding: Set by user.
1759 * - decoding: unused
1764 * amount of previous MV predictors (2a+1 x 2a+1 square)
1765 * - encoding: Set by user.
1766 * - decoding: unused
1768 int last_predictor_count;
1771 * prepass for motion estimation
1772 * - encoding: Set by user.
1773 * - decoding: unused
1778 * motion estimation prepass comparison function
1779 * - encoding: Set by user.
1780 * - decoding: unused
1785 * ME prepass diamond size & shape
1786 * - encoding: Set by user.
1787 * - decoding: unused
1793 * - encoding: Set by user.
1794 * - decoding: unused
1796 int me_subpel_quality;
1799 * callback to negotiate the pixelFormat
1800 * @param fmt is the list of formats which are supported by the codec,
1801 * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
1802 * The first is always the native one.
1803 * @return the chosen format
1804 * - encoding: unused
1805 * - decoding: Set by user, if not set the native format will be chosen.
1807 enum PixelFormat (*get_format)(struct AVCodecContext *s, const enum PixelFormat * fmt);
1810 * DTG active format information (additional aspect ratio
1811 * information only used in DVB MPEG-2 transport streams)
1814 * - encoding: unused
1815 * - decoding: Set by decoder.
1817 int dtg_active_format;
1818 #define FF_DTG_AFD_SAME 8
1819 #define FF_DTG_AFD_4_3 9
1820 #define FF_DTG_AFD_16_9 10
1821 #define FF_DTG_AFD_14_9 11
1822 #define FF_DTG_AFD_4_3_SP_14_9 13
1823 #define FF_DTG_AFD_16_9_SP_14_9 14
1824 #define FF_DTG_AFD_SP_4_3 15
1827 * maximum motion estimation search range in subpel units
1828 * If 0 then no limit.
1830 * - encoding: Set by user.
1831 * - decoding: unused
1836 * intra quantizer bias
1837 * - encoding: Set by user.
1838 * - decoding: unused
1840 int intra_quant_bias;
1841 #define FF_DEFAULT_QUANT_BIAS 999999
1844 * inter quantizer bias
1845 * - encoding: Set by user.
1846 * - decoding: unused
1848 int inter_quant_bias;
1852 * - encoding: unused
1853 * - decoding: Which clrtable should be used for 8bit RGB images.
1854 * Tables have to be stored somewhere. FIXME
1859 * internal_buffer count
1860 * Don't touch, used by libavcodec default_get_buffer().
1862 int internal_buffer_count;
1866 * Don't touch, used by libavcodec default_get_buffer().
1868 void *internal_buffer;
1870 #define FF_LAMBDA_SHIFT 7
1871 #define FF_LAMBDA_SCALE (1<<FF_LAMBDA_SHIFT)
1872 #define FF_QP2LAMBDA 118 ///< factor to convert from H.263 QP to lambda
1873 #define FF_LAMBDA_MAX (256*128-1)
1875 #define FF_QUALITY_SCALE FF_LAMBDA_SCALE //FIXME maybe remove
1877 * Global quality for codecs which cannot change it per frame.
1878 * This should be proportional to MPEG-1/2/4 qscale.
1879 * - encoding: Set by user.
1880 * - decoding: unused
1884 #define FF_CODER_TYPE_VLC 0
1885 #define FF_CODER_TYPE_AC 1
1886 #define FF_CODER_TYPE_RAW 2
1887 #define FF_CODER_TYPE_RLE 3
1888 #define FF_CODER_TYPE_DEFLATE 4
1891 * - encoding: Set by user.
1892 * - decoding: unused
1898 * - encoding: Set by user.
1899 * - decoding: unused
1905 * - encoding: unused
1906 * - decoding: Set by user.
1908 uint8_t * (*realloc)(struct AVCodecContext *s, uint8_t *buf, int buf_size);
1913 * - encoding: unused
1914 * - decoding: Set by user.
1917 #define SLICE_FLAG_CODED_ORDER 0x0001 ///< draw_horiz_band() is called in coded order instead of display
1918 #define SLICE_FLAG_ALLOW_FIELD 0x0002 ///< allow draw_horiz_band() with field slices (MPEG2 field pics)
1919 #define SLICE_FLAG_ALLOW_PLANE 0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)
1922 * XVideo Motion Acceleration
1923 * - encoding: forbidden
1924 * - decoding: set by decoder
1926 int xvmc_acceleration;
1929 * macroblock decision mode
1930 * - encoding: Set by user.
1931 * - decoding: unused
1934 #define FF_MB_DECISION_SIMPLE 0 ///< uses mb_cmp
1935 #define FF_MB_DECISION_BITS 1 ///< chooses the one which needs the fewest bits
1936 #define FF_MB_DECISION_RD 2 ///< rate distortion
1939 * custom intra quantization matrix
1940 * - encoding: Set by user, can be NULL.
1941 * - decoding: Set by libavcodec.
1943 uint16_t *intra_matrix;
1946 * custom inter quantization matrix
1947 * - encoding: Set by user, can be NULL.
1948 * - decoding: Set by libavcodec.
1950 uint16_t *inter_matrix;
1953 * fourcc from the AVI stream header (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1954 * This is used to work around some encoder bugs.
1955 * - encoding: unused
1956 * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1958 unsigned int stream_codec_tag;
1961 * scene change detection threshold
1962 * 0 is default, larger means fewer detected scene changes.
1963 * - encoding: Set by user.
1964 * - decoding: unused
1966 int scenechange_threshold;
1969 * minimum Lagrange multipler
1970 * - encoding: Set by user.
1971 * - decoding: unused
1976 * maximum Lagrange multipler
1977 * - encoding: Set by user.
1978 * - decoding: unused
1983 * palette control structure
1984 * - encoding: ??? (no palette-enabled encoder yet)
1985 * - decoding: Set by user.
1987 struct AVPaletteControl *palctrl;
1990 * noise reduction strength
1991 * - encoding: Set by user.
1992 * - decoding: unused
1994 int noise_reduction;
1997 * Called at the beginning of a frame to get cr buffer for it.
1998 * Buffer type (size, hints) must be the same. libavcodec won't check it.
1999 * libavcodec will pass previous buffer in pic, function should return
2000 * same buffer or new buffer with old frame "painted" into it.
2001 * If pic.data[0] == NULL must behave like get_buffer().
2002 * if CODEC_CAP_DR1 is not set then reget_buffer() must call
2003 * avcodec_default_reget_buffer() instead of providing buffers allocated by
2005 * - encoding: unused
2006 * - decoding: Set by libavcodec., user can override
2008 int (*reget_buffer)(struct AVCodecContext *c, AVFrame *pic);
2011 * Number of bits which should be loaded into the rc buffer before decoding starts.
2012 * - encoding: Set by user.
2013 * - decoding: unused
2015 int rc_initial_buffer_occupancy;
2019 * - encoding: Set by user.
2020 * - decoding: unused
2022 int inter_threshold;
2026 * - encoding: Set by user.
2027 * - decoding: Set by user.
2032 * Simulates errors in the bitstream to test error concealment.
2033 * - encoding: Set by user.
2034 * - decoding: unused
2039 * MP3 antialias algorithm, see FF_AA_* below.
2040 * - encoding: unused
2041 * - decoding: Set by user.
2044 #define FF_AA_AUTO 0
2045 #define FF_AA_FASTINT 1 //not implemented yet
2047 #define FF_AA_FLOAT 3
2049 * quantizer noise shaping
2050 * - encoding: Set by user.
2051 * - decoding: unused
2053 int quantizer_noise_shaping;
2057 * is used to decide how many independent tasks should be passed to execute()
2058 * - encoding: Set by user.
2059 * - decoding: Set by user.
2064 * The codec may call this to execute several independent things.
2065 * It will return only after finishing all tasks.
2066 * The user may replace this with some multithreaded implementation,
2067 * the default implementation will execute the parts serially.
2068 * @param count the number of things to execute
2069 * - encoding: Set by libavcodec, user can override.
2070 * - decoding: Set by libavcodec, user can override.
2072 int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);
2076 * Can be used by execute() to store some per AVCodecContext stuff.
2077 * - encoding: set by execute()
2078 * - decoding: set by execute()
2080 void *thread_opaque;
2083 * Motion estimation threshold below which no motion estimation is
2084 * performed, but instead the user specified motion vectors are used.
2086 * - encoding: Set by user.
2087 * - decoding: unused
2092 * Macroblock threshold below which the user specified macroblock types will be used.
2093 * - encoding: Set by user.
2094 * - decoding: unused
2099 * precision of the intra DC coefficient - 8
2100 * - encoding: Set by user.
2101 * - decoding: unused
2103 int intra_dc_precision;
2106 * noise vs. sse weight for the nsse comparsion function
2107 * - encoding: Set by user.
2108 * - decoding: unused
2113 * Number of macroblock rows at the top which are skipped.
2114 * - encoding: unused
2115 * - decoding: Set by user.
2120 * Number of macroblock rows at the bottom which are skipped.
2121 * - encoding: unused
2122 * - decoding: Set by user.
2128 * - encoding: Set by user.
2129 * - decoding: Set by libavcodec.
2132 #define FF_PROFILE_UNKNOWN -99
2134 #define FF_PROFILE_AAC_MAIN 0
2135 #define FF_PROFILE_AAC_LOW 1
2136 #define FF_PROFILE_AAC_SSR 2
2137 #define FF_PROFILE_AAC_LTP 3
2139 #define FF_PROFILE_H264_BASELINE 66
2140 #define FF_PROFILE_H264_MAIN 77
2141 #define FF_PROFILE_H264_EXTENDED 88
2142 #define FF_PROFILE_H264_HIGH 100
2143 #define FF_PROFILE_H264_HIGH_10 110
2144 #define FF_PROFILE_H264_HIGH_422 122
2145 #define FF_PROFILE_H264_HIGH_444 244
2146 #define FF_PROFILE_H264_CAVLC_444 44
2150 * - encoding: Set by user.
2151 * - decoding: Set by libavcodec.
2154 #define FF_LEVEL_UNKNOWN -99
2157 * low resolution decoding, 1-> 1/2 size, 2->1/4 size
2158 * - encoding: unused
2159 * - decoding: Set by user.
2164 * Bitstream width / height, may be different from width/height if lowres
2165 * or other things are used.
2166 * - encoding: unused
2167 * - decoding: Set by user before init if known. Codec should override / dynamically change if needed.
2169 int coded_width, coded_height;
2172 * frame skip threshold
2173 * - encoding: Set by user.
2174 * - decoding: unused
2176 int frame_skip_threshold;
2180 * - encoding: Set by user.
2181 * - decoding: unused
2183 int frame_skip_factor;
2186 * frame skip exponent
2187 * - encoding: Set by user.
2188 * - decoding: unused
2193 * frame skip comparison function
2194 * - encoding: Set by user.
2195 * - decoding: unused
2200 * Border processing masking, raises the quantizer for mbs on the borders
2202 * - encoding: Set by user.
2203 * - decoding: unused
2205 float border_masking;
2208 * minimum MB lagrange multipler
2209 * - encoding: Set by user.
2210 * - decoding: unused
2215 * maximum MB lagrange multipler
2216 * - encoding: Set by user.
2217 * - decoding: unused
2223 * - encoding: Set by user.
2224 * - decoding: unused
2226 int me_penalty_compensation;
2230 * - encoding: unused
2231 * - decoding: Set by user.
2233 enum AVDiscard skip_loop_filter;
2237 * - encoding: unused
2238 * - decoding: Set by user.
2240 enum AVDiscard skip_idct;
2244 * - encoding: unused
2245 * - decoding: Set by user.
2247 enum AVDiscard skip_frame;
2251 * - encoding: Set by user.
2252 * - decoding: unused
2258 * - encoding: Set by user.
2259 * - decoding: unused
2264 * constant rate factor - quality-based VBR - values ~correspond to qps
2265 * - encoding: Set by user.
2266 * - decoding: unused
2271 * constant quantization parameter rate control method
2272 * - encoding: Set by user.
2273 * - decoding: unused
2279 * - encoding: Set by user.
2280 * - decoding: unused
2285 * number of reference frames
2286 * - encoding: Set by user.
2287 * - decoding: Set by lavc.
2292 * chroma qp offset from luma
2293 * - encoding: Set by user.
2294 * - decoding: unused
2299 * Influences how often B-frames are used.
2300 * - encoding: Set by user.
2301 * - decoding: unused
2306 * trellis RD quantization
2307 * - encoding: Set by user.
2308 * - decoding: unused
2313 * Reduce fluctuations in qp (before curve compression).
2314 * - encoding: Set by user.
2315 * - decoding: unused
2317 float complexityblur;
2320 * in-loop deblocking filter alphac0 parameter
2321 * alpha is in the range -6...6
2322 * - encoding: Set by user.
2323 * - decoding: unused
2328 * in-loop deblocking filter beta parameter
2329 * beta is in the range -6...6
2330 * - encoding: Set by user.
2331 * - decoding: unused
2336 * macroblock subpartition sizes to consider - p8x8, p4x4, b8x8, i8x8, i4x4
2337 * - encoding: Set by user.
2338 * - decoding: unused
2341 #define X264_PART_I4X4 0x001 /* Analyze i4x4 */
2342 #define X264_PART_I8X8 0x002 /* Analyze i8x8 (requires 8x8 transform) */
2343 #define X264_PART_P8X8 0x010 /* Analyze p16x8, p8x16 and p8x8 */
2344 #define X264_PART_P4X4 0x020 /* Analyze p8x4, p4x8, p4x4 */
2345 #define X264_PART_B8X8 0x100 /* Analyze b16x8, b8x16 and b8x8 */
2348 * direct MV prediction mode - 0 (none), 1 (spatial), 2 (temporal), 3 (auto)
2349 * - encoding: Set by user.
2350 * - decoding: unused
2355 * Audio cutoff bandwidth (0 means "automatic")
2356 * - encoding: Set by user.
2357 * - decoding: unused
2362 * Multiplied by qscale for each frame and added to scene_change_score.
2363 * - encoding: Set by user.
2364 * - decoding: unused
2366 int scenechange_factor;
2370 * Note: Value depends upon the compare function used for fullpel ME.
2371 * - encoding: Set by user.
2372 * - decoding: unused
2377 * Adjusts sensitivity of b_frame_strategy 1.
2378 * - encoding: Set by user.
2379 * - decoding: unused
2384 * - encoding: Set by user.
2385 * - decoding: unused
2387 int compression_level;
2388 #define FF_COMPRESSION_DEFAULT -1
2391 * Sets whether to use LPC mode - used by FLAC encoder.
2392 * - encoding: Set by user.
2393 * - decoding: unused
2398 * LPC coefficient precision - used by FLAC encoder
2399 * - encoding: Set by user.
2400 * - decoding: unused
2402 int lpc_coeff_precision;
2405 * - encoding: Set by user.
2406 * - decoding: unused
2408 int min_prediction_order;
2411 * - encoding: Set by user.
2412 * - decoding: unused
2414 int max_prediction_order;
2417 * search method for selecting prediction order
2418 * - encoding: Set by user.
2419 * - decoding: unused
2421 int prediction_order_method;
2424 * - encoding: Set by user.
2425 * - decoding: unused
2427 int min_partition_order;
2430 * - encoding: Set by user.
2431 * - decoding: unused
2433 int max_partition_order;
2436 * GOP timecode frame start number, in non drop frame format
2437 * - encoding: Set by user.
2438 * - decoding: unused
2440 int64_t timecode_frame_start;
2442 #if LIBAVCODEC_VERSION_MAJOR < 53
2444 * Decoder should decode to this many channels if it can (0 for default)
2445 * - encoding: unused
2446 * - decoding: Set by user.
2447 * @deprecated Deprecated in favor of request_channel_layout.
2449 int request_channels;
2453 * Percentage of dynamic range compression to be applied by the decoder.
2454 * The default value is 1.0, corresponding to full compression.
2455 * - encoding: unused
2456 * - decoding: Set by user.
2461 * opaque 64bit number (generally a PTS) that will be reordered and
2462 * output in AVFrame.reordered_opaque
2463 * - encoding: unused
2464 * - decoding: Set by user.
2466 int64_t reordered_opaque;
2469 * Bits per sample/pixel of internal libavcodec pixel/sample format.
2470 * This field is applicable only when sample_fmt is SAMPLE_FMT_S32.
2471 * - encoding: set by user.
2472 * - decoding: set by libavcodec.
2474 int bits_per_raw_sample;
2477 * Audio channel layout.
2478 * - encoding: set by user.
2479 * - decoding: set by libavcodec.
2481 int64_t channel_layout;
2484 * Request decoder to use this channel layout if it can (0 for default)
2485 * - encoding: unused
2486 * - decoding: Set by user.
2488 int64_t request_channel_layout;
2491 * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
2492 * - encoding: Set by user.
2493 * - decoding: unused.
2495 float rc_max_available_vbv_use;
2498 * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
2499 * - encoding: Set by user.
2500 * - decoding: unused.
2502 float rc_min_vbv_overflow_use;
2505 * Hardware accelerator in use
2506 * - encoding: unused.
2507 * - decoding: Set by libavcodec
2509 struct AVHWAccel *hwaccel;
2512 * For some codecs, the time base is closer to the field rate than the frame rate.
2513 * Most notably, H.264 and MPEG-2 specify time_base as half of frame duration
2514 * if no telecine is used ...
2516 * Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
2518 int ticks_per_frame;
2521 * Hardware accelerator context.
2522 * For some hardware accelerators, a global context needs to be
2523 * provided by the user. In that case, this holds display-dependent
2524 * data FFmpeg cannot instantiate itself. Please refer to the
2525 * FFmpeg HW accelerator documentation to know how to fill this
2526 * is. e.g. for VA API, this is a struct vaapi_context.
2527 * - encoding: unused
2528 * - decoding: Set by user
2530 void *hwaccel_context;
2533 * Chromaticity coordinates of the source primaries.
2534 * - encoding: Set by user
2535 * - decoding: Set by libavcodec
2537 enum AVColorPrimaries color_primaries;
2540 * Color Transfer Characteristic.
2541 * - encoding: Set by user
2542 * - decoding: Set by libavcodec
2544 enum AVColorTransferCharacteristic color_trc;
2547 * YUV colorspace type.
2548 * - encoding: Set by user
2549 * - decoding: Set by libavcodec
2551 enum AVColorSpace colorspace;
2554 * MPEG vs JPEG YUV range.
2555 * - encoding: Set by user
2556 * - decoding: Set by libavcodec
2558 enum AVColorRange color_range;
2561 * This defines the location of chroma samples.
2562 * - encoding: Set by user
2563 * - decoding: Set by libavcodec
2565 enum AVChromaLocation chroma_sample_location;
2568 * The codec may call this to execute several independent things.
2569 * It will return only after finishing all tasks.
2570 * The user may replace this with some multithreaded implementation,
2571 * the default implementation will execute the parts serially.
2572 * Also see avcodec_thread_init and e.g. the --enable-pthread configure option.
2573 * @param c context passed also to func
2574 * @param count the number of things to execute
2575 * @param arg2 argument passed unchanged to func
2576 * @param ret return values of executed functions, must have space for "count" values. May be NULL.
2577 * @param func function that will be called count times, with jobnr from 0 to count-1.
2578 * threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
2579 * two instances of func executing at the same time will have the same threadnr.
2580 * @return always 0 currently, but code should handle a future improvement where when any call to func
2581 * returns < 0 no further calls to func may be done and < 0 is returned.
2582 * - encoding: Set by libavcodec, user can override.
2583 * - decoding: Set by libavcodec, user can override.
2585 int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);
2588 * explicit P-frame weighted prediction analysis method
2590 * 1: fast blind weighting (one reference duplicate with -1 offset)
2591 * 2: smart weighting (full fade detection analysis)
2592 * - encoding: Set by user.
2593 * - decoding: unused
2595 int weighted_p_pred;
2601 typedef struct AVCodec {
2603 * Name of the codec implementation.
2604 * The name is globally unique among encoders and among decoders (but an
2605 * encoder and a decoder can share the same name).
2606 * This is the primary way to find a codec from the user perspective.
2609 enum CodecType type;
2612 int (*init)(AVCodecContext *);
2613 int (*encode)(AVCodecContext *, uint8_t *buf, int buf_size, void *data);
2614 int (*close)(AVCodecContext *);
2615 int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);
2617 * Codec capabilities.
2621 struct AVCodec *next;
2624 * Will be called when seeking
2626 void (*flush)(AVCodecContext *);
2627 const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
2628 const enum PixelFormat *pix_fmts; ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
2630 * Descriptive name for the codec, meant to be more human readable than name.
2631 * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
2633 const char *long_name;
2634 const int *supported_samplerates; ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
2635 const enum SampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
2636 const int64_t *channel_layouts; ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
2642 typedef struct AVHWAccel {
2644 * Name of the hardware accelerated codec.
2645 * The name is globally unique among encoders and among decoders (but an
2646 * encoder and a decoder can share the same name).
2651 * Type of codec implemented by the hardware accelerator.
2653 * See CODEC_TYPE_xxx
2655 enum CodecType type;
2658 * Codec implemented by the hardware accelerator.
2665 * Supported pixel format.
2667 * Only hardware accelerated formats are supported here.
2669 enum PixelFormat pix_fmt;
2672 * Hardware accelerated codec capabilities.
2673 * see FF_HWACCEL_CODEC_CAP_*
2677 struct AVHWAccel *next;
2680 * Called at the beginning of each frame or field picture.
2682 * Meaningful frame information (codec specific) is guaranteed to
2683 * be parsed at this point. This function is mandatory.
2685 * Note that buf can be NULL along with buf_size set to 0.
2686 * Otherwise, this means the whole frame is available at this point.
2688 * @param avctx the codec context
2689 * @param buf the frame data buffer base
2690 * @param buf_size the size of the frame in bytes
2691 * @return zero if successful, a negative value otherwise
2693 int (*start_frame)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
2696 * Callback for each slice.
2698 * Meaningful slice information (codec specific) is guaranteed to
2699 * be parsed at this point. This function is mandatory.
2701 * @param avctx the codec context
2702 * @param buf the slice data buffer base
2703 * @param buf_size the size of the slice in bytes
2704 * @return zero if successful, a negative value otherwise
2706 int (*decode_slice)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
2709 * Called at the end of each frame or field picture.
2711 * The whole picture is parsed at this point and can now be sent
2712 * to the hardware accelerator. This function is mandatory.
2714 * @param avctx the codec context
2715 * @return zero if successful, a negative value otherwise
2717 int (*end_frame)(AVCodecContext *avctx);
2720 * Size of HW accelerator private data.
2722 * Private data is allocated with av_mallocz() before
2723 * AVCodecContext.get_buffer() and deallocated after
2724 * AVCodecContext.release_buffer().
2730 * four components are given, that's all.
2731 * the last component is alpha
2733 typedef struct AVPicture {
2735 int linesize[4]; ///< number of bytes per line
2738 #if LIBAVCODEC_VERSION_MAJOR < 53
2741 * This structure defines a method for communicating palette changes
2742 * between and demuxer and a decoder.
2744 * @deprecated Use AVPacket to send palette changes instead.
2745 * This is totally broken.
2747 #define AVPALETTE_SIZE 1024
2748 #define AVPALETTE_COUNT 256
2749 typedef struct AVPaletteControl {
2751 /* Demuxer sets this to 1 to indicate the palette has changed;
2752 * decoder resets to 0. */
2753 int palette_changed;
2755 /* 4-byte ARGB palette entries, stored in native byte order; note that
2756 * the individual palette components should be on a 8-bit scale; if
2757 * the palette data comes from an IBM VGA native format, the component
2758 * data is probably 6 bits in size and needs to be scaled. */
2759 unsigned int palette[AVPALETTE_COUNT];
2761 } AVPaletteControl attribute_deprecated;
2764 enum AVSubtitleType {
2767 SUBTITLE_BITMAP, ///< A bitmap, pict will be set
2770 * Plain text, the text field must be set by the decoder and is
2771 * authoritative. ass and pict fields may contain approximations.
2776 * Formatted text, the ass field must be set by the decoder and is
2777 * authoritative. pict and text fields may contain approximations.
2782 typedef struct AVSubtitleRect {
2783 int x; ///< top left corner of pict, undefined when pict is not set
2784 int y; ///< top left corner of pict, undefined when pict is not set
2785 int w; ///< width of pict, undefined when pict is not set
2786 int h; ///< height of pict, undefined when pict is not set
2787 int nb_colors; ///< number of colors in pict, undefined when pict is not set
2790 * data+linesize for the bitmap of this subtitle.
2791 * can be set for text/ass as well once they where rendered
2794 enum AVSubtitleType type;
2796 char *text; ///< 0 terminated plain UTF-8 text
2799 * 0 terminated ASS/SSA compatible event line.
2800 * The pressentation of this is unaffected by the other values in this
2806 typedef struct AVSubtitle {
2807 uint16_t format; /* 0 = graphics */
2808 uint32_t start_display_time; /* relative to packet pts, in ms */
2809 uint32_t end_display_time; /* relative to packet pts, in ms */
2811 AVSubtitleRect **rects;
2812 int64_t pts; ///< Same as packet pts, in AV_TIME_BASE
2815 /* packet functions */
2818 * @deprecated use NULL instead
2820 attribute_deprecated void av_destruct_packet_nofree(AVPacket *pkt);
2823 * Default packet destructor.
2825 void av_destruct_packet(AVPacket *pkt);
2828 * Initialize optional fields of a packet with default values.
2832 void av_init_packet(AVPacket *pkt);
2835 * Allocate the payload of a packet and initialize its fields with
2839 * @param size wanted payload size
2840 * @return 0 if OK, AVERROR_xxx otherwise
2842 int av_new_packet(AVPacket *pkt, int size);
2845 * Reduce packet size, correctly zeroing padding
2848 * @param size new size
2850 void av_shrink_packet(AVPacket *pkt, int size);
2853 * @warning This is a hack - the packet memory allocation stuff is broken. The
2854 * packet is allocated if it was not really allocated.
2856 int av_dup_packet(AVPacket *pkt);
2861 * @param pkt packet to free
2863 void av_free_packet(AVPacket *pkt);
2867 struct ReSampleContext;
2868 struct AVResampleContext;
2870 typedef struct ReSampleContext ReSampleContext;
2872 #if LIBAVCODEC_VERSION_MAJOR < 53
2874 * @deprecated Use av_audio_resample_init() instead.
2876 attribute_deprecated ReSampleContext *audio_resample_init(int output_channels, int input_channels,
2877 int output_rate, int input_rate);
2880 * Initializes audio resampling context
2882 * @param output_channels number of output channels
2883 * @param input_channels number of input channels
2884 * @param output_rate output sample rate
2885 * @param input_rate input sample rate
2886 * @param sample_fmt_out requested output sample format
2887 * @param sample_fmt_in input sample format
2888 * @param filter_length length of each FIR filter in the filterbank relative to the cutoff freq
2889 * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
2890 * @param linear If 1 then the used FIR filter will be linearly interpolated
2891 between the 2 closest, if 0 the closest will be used
2892 * @param cutoff cutoff frequency, 1.0 corresponds to half the output sampling rate
2893 * @return allocated ReSampleContext, NULL if error occured
2895 ReSampleContext *av_audio_resample_init(int output_channels, int input_channels,
2896 int output_rate, int input_rate,
2897 enum SampleFormat sample_fmt_out,
2898 enum SampleFormat sample_fmt_in,
2899 int filter_length, int log2_phase_count,
2900 int linear, double cutoff);
2902 int audio_resample(ReSampleContext *s, short *output, short *input, int nb_samples);
2903 void audio_resample_close(ReSampleContext *s);
2907 * Initializes an audio resampler.
2908 * Note, if either rate is not an integer then simply scale both rates up so they are.
2909 * @param filter_length length of each FIR filter in the filterbank relative to the cutoff freq
2910 * @param log2_phase_count log2 of the number of entries in the polyphase filterbank
2911 * @param linear If 1 then the used FIR filter will be linearly interpolated
2912 between the 2 closest, if 0 the closest will be used
2913 * @param cutoff cutoff frequency, 1.0 corresponds to half the output sampling rate
2915 struct AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_length, int log2_phase_count, int linear, double cutoff);
2919 * @param src an array of unconsumed samples
2920 * @param consumed the number of samples of src which have been consumed are returned here
2921 * @param src_size the number of unconsumed samples available
2922 * @param dst_size the amount of space in samples available in dst
2923 * @param update_ctx If this is 0 then the context will not be modified, that way several channels can be resampled with the same context.
2924 * @return the number of samples written in dst or -1 if an error occurred
2926 int av_resample(struct AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx);
2930 * Compensates samplerate/timestamp drift. The compensation is done by changing
2931 * the resampler parameters, so no audible clicks or similar distortions occur
2932 * @param compensation_distance distance in output samples over which the compensation should be performed
2933 * @param sample_delta number of output samples which should be output less
2935 * example: av_resample_compensate(c, 10, 500)
2936 * here instead of 510 samples only 500 samples would be output
2938 * note, due to rounding the actual compensation might be slightly different,
2939 * especially if the compensation_distance is large and the in_rate used during init is small
2941 void av_resample_compensate(struct AVResampleContext *c, int sample_delta, int compensation_distance);
2942 void av_resample_close(struct AVResampleContext *c);
2945 * Allocate memory for a picture. Call avpicture_free to free it.
2947 * @param picture the picture to be filled in
2948 * @param pix_fmt the format of the picture
2949 * @param width the width of the picture
2950 * @param height the height of the picture
2951 * @return zero if successful, a negative value if not
2953 int avpicture_alloc(AVPicture *picture, enum PixelFormat pix_fmt, int width, int height);
2956 * Free a picture previously allocated by avpicture_alloc().
2958 * @param picture the AVPicture to be freed
2960 void avpicture_free(AVPicture *picture);
2963 * Fill in the AVPicture fields.
2964 * The fields of the given AVPicture are filled in by using the 'ptr' address
2965 * which points to the image data buffer. Depending on the specified picture
2966 * format, one or multiple image data pointers and line sizes will be set.
2967 * If a planar format is specified, several pointers will be set pointing to
2968 * the different picture planes and the line sizes of the different planes
2969 * will be stored in the lines_sizes array.
2970 * Call with ptr == NULL to get the required size for the ptr buffer.
2972 * @param picture AVPicture whose fields are to be filled in
2973 * @param ptr Buffer which will contain or contains the actual image data
2974 * @param pix_fmt The format in which the picture data is stored.
2975 * @param width the width of the image in pixels
2976 * @param height the height of the image in pixels
2977 * @return size of the image data in bytes
2979 int avpicture_fill(AVPicture *picture, uint8_t *ptr,
2980 enum PixelFormat pix_fmt, int width, int height);
2981 int avpicture_layout(const AVPicture* src, enum PixelFormat pix_fmt, int width, int height,
2982 unsigned char *dest, int dest_size);
2985 * Calculate the size in bytes that a picture of the given width and height
2986 * would occupy if stored in the given picture format.
2987 * Note that this returns the size of a compact representation as generated
2988 * by avpicture_layout, which can be smaller than the size required for e.g.
2991 * @param pix_fmt the given picture format
2992 * @param width the width of the image
2993 * @param height the height of the image
2994 * @return Image data size in bytes or -1 on error (e.g. too large dimensions).
2996 int avpicture_get_size(enum PixelFormat pix_fmt, int width, int height);
2997 void avcodec_get_chroma_sub_sample(enum PixelFormat pix_fmt, int *h_shift, int *v_shift);
2998 const char *avcodec_get_pix_fmt_name(enum PixelFormat pix_fmt);
2999 void avcodec_set_dimensions(AVCodecContext *s, int width, int height);
3001 #if LIBAVCODEC_VERSION_MAJOR < 53
3003 * Returns the pixel format corresponding to the name name.
3005 * If there is no pixel format with name name, then looks for a
3006 * pixel format with the name corresponding to the native endian
3008 * For example in a little-endian system, first looks for "gray16",
3009 * then for "gray16le".
3011 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
3013 * @deprecated Deprecated in favor of av_get_pix_fmt().
3015 attribute_deprecated enum PixelFormat avcodec_get_pix_fmt(const char* name);
3019 * Returns a value representing the fourCC code associated to the
3020 * pixel format pix_fmt, or 0 if no associated fourCC code can be
3023 unsigned int avcodec_pix_fmt_to_codec_tag(enum PixelFormat pix_fmt);
3025 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
3026 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
3027 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
3028 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
3029 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
3030 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
3033 * Computes what kind of losses will occur when converting from one specific
3034 * pixel format to another.
3035 * When converting from one pixel format to another, information loss may occur.
3036 * For example, when converting from RGB24 to GRAY, the color information will
3037 * be lost. Similarly, other losses occur when converting from some formats to
3038 * other formats. These losses can involve loss of chroma, but also loss of
3039 * resolution, loss of color depth, loss due to the color space conversion, loss
3040 * of the alpha bits or loss due to color quantization.
3041 * avcodec_get_fix_fmt_loss() informs you about the various types of losses
3042 * which will occur when converting from one pixel format to another.
3044 * @param[in] dst_pix_fmt destination pixel format
3045 * @param[in] src_pix_fmt source pixel format
3046 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
3047 * @return Combination of flags informing you what kind of losses will occur.
3049 int avcodec_get_pix_fmt_loss(enum PixelFormat dst_pix_fmt, enum PixelFormat src_pix_fmt,
3053 * Finds the best pixel format to convert to given a certain source pixel
3054 * format. When converting from one pixel format to another, information loss
3055 * may occur. For example, when converting from RGB24 to GRAY, the color
3056 * information will be lost. Similarly, other losses occur when converting from
3057 * some formats to other formats. avcodec_find_best_pix_fmt() searches which of
3058 * the given pixel formats should be used to suffer the least amount of loss.
3059 * The pixel formats from which it chooses one, are determined by the
3060 * pix_fmt_mask parameter.
3063 * src_pix_fmt = PIX_FMT_YUV420P;
3064 * pix_fmt_mask = (1 << PIX_FMT_YUV422P) || (1 << PIX_FMT_RGB24);
3065 * dst_pix_fmt = avcodec_find_best_pix_fmt(pix_fmt_mask, src_pix_fmt, alpha, &loss);
3068 * @param[in] pix_fmt_mask bitmask determining which pixel format to choose from
3069 * @param[in] src_pix_fmt source pixel format
3070 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
3071 * @param[out] loss_ptr Combination of flags informing you what kind of losses will occur.
3072 * @return The best pixel format to convert to or -1 if none was found.
3074 enum PixelFormat avcodec_find_best_pix_fmt(int64_t pix_fmt_mask, enum PixelFormat src_pix_fmt,
3075 int has_alpha, int *loss_ptr);
3079 * Print in buf the string corresponding to the pixel format with
3080 * number pix_fmt, or an header if pix_fmt is negative.
3082 * @param[in] buf the buffer where to write the string
3083 * @param[in] buf_size the size of buf
3084 * @param[in] pix_fmt the number of the pixel format to print the corresponding info string, or
3085 * a negative value to print the corresponding header.
3086 * Meaningful values for obtaining a pixel format info vary from 0 to PIX_FMT_NB -1.
3088 void avcodec_pix_fmt_string (char *buf, int buf_size, enum PixelFormat pix_fmt);
3090 #define FF_ALPHA_TRANSP 0x0001 /* image has some totally transparent pixels */
3091 #define FF_ALPHA_SEMI_TRANSP 0x0002 /* image has some transparent pixels */
3094 * Tell if an image really has transparent alpha values.
3095 * @return ored mask of FF_ALPHA_xxx constants
3097 int img_get_alpha_info(const AVPicture *src,
3098 enum PixelFormat pix_fmt, int width, int height);
3100 /* deinterlace a picture */
3101 /* deinterlace - if not supported return -1 */
3102 int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
3103 enum PixelFormat pix_fmt, int width, int height);
3105 /* external high level API */
3108 * If c is NULL, returns the first registered codec,
3109 * if c is non-NULL, returns the next registered codec after c,
3110 * or NULL if c is the last one.
3112 AVCodec *av_codec_next(AVCodec *c);
3115 * Returns the LIBAVCODEC_VERSION_INT constant.
3117 unsigned avcodec_version(void);
3120 * Returns the libavcodec build-time configuration.
3122 const char *avcodec_configuration(void);
3125 * Returns the libavcodec license.
3127 const char *avcodec_license(void);
3130 * Initializes libavcodec.
3132 * @warning This function must be called before any other libavcodec
3135 void avcodec_init(void);
3137 #if LIBAVCODEC_VERSION_MAJOR < 53
3139 * @deprecated Deprecated in favor of avcodec_register().
3141 attribute_deprecated void register_avcodec(AVCodec *codec);
3145 * Register the codec codec and initialize libavcodec.
3147 * @see avcodec_init()
3149 void avcodec_register(AVCodec *codec);
3152 * Finds a registered encoder with a matching codec ID.
3154 * @param id CodecID of the requested encoder
3155 * @return An encoder if one was found, NULL otherwise.
3157 AVCodec *avcodec_find_encoder(enum CodecID id);
3160 * Finds a registered encoder with the specified name.
3162 * @param name name of the requested encoder
3163 * @return An encoder if one was found, NULL otherwise.
3165 AVCodec *avcodec_find_encoder_by_name(const char *name);
3168 * Finds a registered decoder with a matching codec ID.
3170 * @param id CodecID of the requested decoder
3171 * @return A decoder if one was found, NULL otherwise.
3173 AVCodec *avcodec_find_decoder(enum CodecID id);
3176 * Finds a registered decoder with the specified name.
3178 * @param name name of the requested decoder
3179 * @return A decoder if one was found, NULL otherwise.
3181 AVCodec *avcodec_find_decoder_by_name(const char *name);
3182 void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);
3185 * Sets the fields of the given AVCodecContext to default values.
3187 * @param s The AVCodecContext of which the fields should be set to default values.
3189 void avcodec_get_context_defaults(AVCodecContext *s);
3191 /** THIS FUNCTION IS NOT YET PART OF THE PUBLIC API!
3192 * we WILL change its arguments and name a few times! */
3193 void avcodec_get_context_defaults2(AVCodecContext *s, enum CodecType);
3196 * Allocates an AVCodecContext and sets its fields to default values. The
3197 * resulting struct can be deallocated by simply calling av_free().
3199 * @return An AVCodecContext filled with default values or NULL on failure.
3200 * @see avcodec_get_context_defaults
3202 AVCodecContext *avcodec_alloc_context(void);
3204 /** THIS FUNCTION IS NOT YET PART OF THE PUBLIC API!
3205 * we WILL change its arguments and name a few times! */
3206 AVCodecContext *avcodec_alloc_context2(enum CodecType);
3209 * Sets the fields of the given AVFrame to default values.
3211 * @param pic The AVFrame of which the fields should be set to default values.
3213 void avcodec_get_frame_defaults(AVFrame *pic);
3216 * Allocates an AVFrame and sets its fields to default values. The resulting
3217 * struct can be deallocated by simply calling av_free().
3219 * @return An AVFrame filled with default values or NULL on failure.
3220 * @see avcodec_get_frame_defaults
3222 AVFrame *avcodec_alloc_frame(void);
3224 int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
3225 void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
3226 int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic);
3227 void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);
3230 * Checks if the given dimension of a picture is valid, meaning that all
3231 * bytes of the picture can be addressed with a signed int.
3233 * @param[in] w Width of the picture.
3234 * @param[in] h Height of the picture.
3235 * @return Zero if valid, a negative value if invalid.
3237 int avcodec_check_dimensions(void *av_log_ctx, unsigned int w, unsigned int h);
3238 enum PixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum PixelFormat * fmt);
3240 int avcodec_thread_init(AVCodecContext *s, int thread_count);
3241 void avcodec_thread_free(AVCodecContext *s);
3242 int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
3243 int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
3244 int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count);
3245 //FIXME func typedef
3248 * Initializes the AVCodecContext to use the given AVCodec. Prior to using this
3249 * function the context has to be allocated.
3251 * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
3252 * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
3253 * retrieving a codec.
3255 * @warning This function is not thread safe!
3258 * avcodec_register_all();
3259 * codec = avcodec_find_decoder(CODEC_ID_H264);
3263 * context = avcodec_alloc_context();
3265 * if (avcodec_open(context, codec) < 0)
3269 * @param avctx The context which will be set up to use the given codec.
3270 * @param codec The codec to use within the context.
3271 * @return zero on success, a negative value on error
3272 * @see avcodec_alloc_context, avcodec_find_decoder, avcodec_find_encoder
3274 int avcodec_open(AVCodecContext *avctx, AVCodec *codec);
3276 #if LIBAVCODEC_VERSION_MAJOR < 53
3278 * Decodes an audio frame from buf into samples.
3279 * Wrapper function which calls avcodec_decode_audio3.
3281 * @deprecated Use avcodec_decode_audio3 instead.
3282 * @param avctx the codec context
3283 * @param[out] samples the output buffer
3284 * @param[in,out] frame_size_ptr the output buffer size in bytes
3285 * @param[in] buf the input buffer
3286 * @param[in] buf_size the input buffer size in bytes
3287 * @return On error a negative value is returned, otherwise the number of bytes
3288 * used or zero if no frame could be decompressed.
3290 attribute_deprecated int avcodec_decode_audio2(AVCodecContext *avctx, int16_t *samples,
3291 int *frame_size_ptr,
3292 const uint8_t *buf, int buf_size);
3296 * Decodes the audio frame of size avpkt->size from avpkt->data into samples.
3297 * Some decoders may support multiple frames in a single AVPacket, such
3298 * decoders would then just decode the first frame. In this case,
3299 * avcodec_decode_audio3 has to be called again with an AVPacket that contains
3300 * the remaining data in order to decode the second frame etc.
3302 * could be outputted, frame_size_ptr is zero. Otherwise, it is the
3303 * decompressed frame size in bytes.
3305 * @warning You must set frame_size_ptr to the allocated size of the
3306 * output buffer before calling avcodec_decode_audio3().
3308 * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
3309 * the actual read bytes because some optimized bitstream readers read 32 or 64
3310 * bits at once and could read over the end.
3312 * @warning The end of the input buffer avpkt->data should be set to 0 to ensure that
3313 * no overreading happens for damaged MPEG streams.
3315 * @note You might have to align the input buffer avpkt->data and output buffer
3316 * samples. The alignment requirements depend on the CPU: On some CPUs it isn't
3317 * necessary at all, on others it won't work at all if not aligned and on others
3318 * it will work but it will have an impact on performance.
3320 * In practice, avpkt->data should have 4 byte alignment at minimum and
3321 * samples should be 16 byte aligned unless the CPU doesn't need it
3322 * (AltiVec and SSE do).
3324 * @param avctx the codec context
3325 * @param[out] samples the output buffer, sample type in avctx->sample_fmt
3326 * @param[in,out] frame_size_ptr the output buffer size in bytes
3327 * @param[in] avpkt The input AVPacket containing the input buffer.
3328 * You can create such packet with av_init_packet() and by then setting
3329 * data and size, some decoders might in addition need other fields.
3330 * All decoders are designed to use the least fields possible though.
3331 * @return On error a negative value is returned, otherwise the number of bytes
3332 * used or zero if no frame data was decompressed (used) from the input AVPacket.
3334 int avcodec_decode_audio3(AVCodecContext *avctx, int16_t *samples,
3335 int *frame_size_ptr,
3338 #if LIBAVCODEC_VERSION_MAJOR < 53
3340 * Decodes a video frame from buf into picture.
3341 * Wrapper function which calls avcodec_decode_video2.
3343 * @deprecated Use avcodec_decode_video2 instead.
3344 * @param avctx the codec context
3345 * @param[out] picture The AVFrame in which the decoded video frame will be stored.
3346 * @param[in] buf the input buffer
3347 * @param[in] buf_size the size of the input buffer in bytes
3348 * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
3349 * @return On error a negative value is returned, otherwise the number of bytes
3350 * used or zero if no frame could be decompressed.
3352 attribute_deprecated int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture,
3353 int *got_picture_ptr,
3354 const uint8_t *buf, int buf_size);
3358 * Decodes the video frame of size avpkt->size from avpkt->data into picture.
3359 * Some decoders may support multiple frames in a single AVPacket, such
3360 * decoders would then just decode the first frame.
3362 * @warning The input buffer must be FF_INPUT_BUFFER_PADDING_SIZE larger than
3363 * the actual read bytes because some optimized bitstream readers read 32 or 64
3364 * bits at once and could read over the end.
3366 * @warning The end of the input buffer buf should be set to 0 to ensure that
3367 * no overreading happens for damaged MPEG streams.
3369 * @note You might have to align the input buffer avpkt->data.
3370 * The alignment requirements depend on the CPU: on some CPUs it isn't
3371 * necessary at all, on others it won't work at all if not aligned and on others
3372 * it will work but it will have an impact on performance.
3374 * In practice, avpkt->data should have 4 byte alignment at minimum.
3376 * @note Some codecs have a delay between input and output, these need to be
3377 * fed with avpkt->data=NULL, avpkt->size=0 at the end to return the remaining frames.
3379 * @param avctx the codec context
3380 * @param[out] picture The AVFrame in which the decoded video frame will be stored.
3381 * @param[in] avpkt The input AVpacket containing the input buffer.
3382 * You can create such packet with av_init_packet() and by then setting
3383 * data and size, some decoders might in addition need other fields like
3384 * flags&PKT_FLAG_KEY. All decoders are designed to use the least
3386 * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
3387 * @return On error a negative value is returned, otherwise the number of bytes
3388 * used or zero if no frame could be decompressed.
3390 int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
3391 int *got_picture_ptr,
3394 #if LIBAVCODEC_VERSION_MAJOR < 53
3395 /* Decode a subtitle message. Return -1 if error, otherwise return the
3396 * number of bytes used. If no subtitle could be decompressed,
3397 * got_sub_ptr is zero. Otherwise, the subtitle is stored in *sub. */
3398 attribute_deprecated int avcodec_decode_subtitle(AVCodecContext *avctx, AVSubtitle *sub,
3400 const uint8_t *buf, int buf_size);
3404 * Decodes a subtitle message.
3405 * Returns a negative value on error, otherwise returns the number of bytes used.
3406 * If no subtitle could be decompressed, got_sub_ptr is zero.
3407 * Otherwise, the subtitle is stored in *sub.
3409 * @param avctx the codec context
3410 * @param[out] sub The AVSubtitle in which the decoded subtitle will be stored.
3411 * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
3412 * @param[in] avpkt The input AVPacket containing the input buffer.
3414 int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
3417 int avcodec_parse_frame(AVCodecContext *avctx, uint8_t **pdata,
3419 uint8_t *buf, int buf_size);
3422 * Encodes an audio frame from samples into buf.
3424 * @note The output buffer should be at least FF_MIN_BUFFER_SIZE bytes large.
3425 * However, for PCM audio the user will know how much space is needed
3426 * because it depends on the value passed in buf_size as described
3427 * below. In that case a lower value can be used.
3429 * @param avctx the codec context
3430 * @param[out] buf the output buffer
3431 * @param[in] buf_size the output buffer size
3432 * @param[in] samples the input buffer containing the samples
3433 * The number of samples read from this buffer is frame_size*channels,
3434 * both of which are defined in avctx.
3435 * For PCM audio the number of samples read from samples is equal to
3436 * buf_size * input_sample_size / output_sample_size.
3437 * @return On error a negative value is returned, on success zero or the number
3438 * of bytes used to encode the data read from the input buffer.
3440 int avcodec_encode_audio(AVCodecContext *avctx, uint8_t *buf, int buf_size,
3441 const short *samples);
3444 * Encodes a video frame from pict into buf.
3445 * The input picture should be
3446 * stored using a specific format, namely avctx.pix_fmt.
3448 * @param avctx the codec context
3449 * @param[out] buf the output buffer for the bitstream of encoded frame
3450 * @param[in] buf_size the size of the output buffer in bytes
3451 * @param[in] pict the input picture to encode
3452 * @return On error a negative value is returned, on success zero or the number
3453 * of bytes used from the output buffer.
3455 int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
3456 const AVFrame *pict);
3457 int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
3458 const AVSubtitle *sub);
3460 int avcodec_close(AVCodecContext *avctx);
3463 * Register all the codecs, parsers and bitstream filters which were enabled at
3464 * configuration time. If you do not call this function you can select exactly
3465 * which formats you want to support, by using the individual registration
3468 * @see avcodec_register
3469 * @see av_register_codec_parser
3470 * @see av_register_bitstream_filter
3472 void avcodec_register_all(void);
3475 * Flush buffers, should be called when seeking or when switching to a different stream.
3477 void avcodec_flush_buffers(AVCodecContext *avctx);
3479 void avcodec_default_free_buffers(AVCodecContext *s);
3481 /* misc useful functions */
3484 * Returns a single letter to describe the given picture type pict_type.
3486 * @param[in] pict_type the picture type
3487 * @return A single character representing the picture type.
3489 char av_get_pict_type_char(int pict_type);
3492 * Returns codec bits per sample.
3494 * @param[in] codec_id the codec
3495 * @return Number of bits per sample or zero if unknown for the given codec.
3497 int av_get_bits_per_sample(enum CodecID codec_id);
3500 * Returns sample format bits per sample.
3502 * @param[in] sample_fmt the sample format
3503 * @return Number of bits per sample or zero if unknown for the given sample format.
3505 int av_get_bits_per_sample_format(enum SampleFormat sample_fmt);
3508 typedef struct AVCodecParserContext {
3510 struct AVCodecParser *parser;
3511 int64_t frame_offset; /* offset of the current frame */
3512 int64_t cur_offset; /* current offset
3513 (incremented by each av_parser_parse()) */
3514 int64_t next_frame_offset; /* offset of the next frame */
3516 int pict_type; /* XXX: Put it back in AVCodecContext. */
3518 * This field is used for proper frame duration computation in lavf.
3519 * It signals, how much longer the frame duration of the current frame
3520 * is compared to normal frame duration.
3522 * frame_duration = (1 + repeat_pict) * time_base
3524 * It is used by codecs like H.264 to display telecined material.
3526 int repeat_pict; /* XXX: Put it back in AVCodecContext. */
3527 int64_t pts; /* pts of the current frame */
3528 int64_t dts; /* dts of the current frame */
3533 int fetch_timestamp;
3535 #define AV_PARSER_PTS_NB 4
3536 int cur_frame_start_index;
3537 int64_t cur_frame_offset[AV_PARSER_PTS_NB];
3538 int64_t cur_frame_pts[AV_PARSER_PTS_NB];
3539 int64_t cur_frame_dts[AV_PARSER_PTS_NB];
3542 #define PARSER_FLAG_COMPLETE_FRAMES 0x0001
3544 int64_t offset; ///< byte offset from starting packet start
3545 int64_t cur_frame_end[AV_PARSER_PTS_NB];
3548 * Set by parser to 1 for key frames and 0 for non-key frames.
3549 * It is initialized to -1, so if the parser doesn't set this flag,
3550 * old-style fallback using FF_I_TYPE picture type as key frames
3556 * Time difference in stream time base units from the pts of this
3557 * packet to the point at which the output from the decoder has converged
3558 * independent from the availability of previous frames. That is, the
3559 * frames are virtually identical no matter if decoding started from
3560 * the very first frame or from this keyframe.
3561 * Is AV_NOPTS_VALUE if unknown.
3562 * This field is not the display duration of the current frame.
3564 * The purpose of this field is to allow seeking in streams that have no
3565 * keyframes in the conventional sense. It corresponds to the
3566 * recovery point SEI in H.264 and match_time_delta in NUT. It is also
3567 * essential for some types of subtitle streams to ensure that all
3568 * subtitles are correctly displayed after seeking.
3570 int64_t convergence_duration;
3572 // Timestamp generation support:
3574 * Synchronization point for start of timestamp generation.
3576 * Set to >0 for sync point, 0 for no sync point and <0 for undefined
3579 * For example, this corresponds to presence of H.264 buffering period
3585 * Offset of the current timestamp against last timestamp sync point in
3586 * units of AVCodecContext.time_base.
3588 * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
3589 * contain a valid timestamp offset.
3591 * Note that the timestamp of sync point has usually a nonzero
3592 * dts_ref_dts_delta, which refers to the previous sync point. Offset of
3593 * the next frame after timestamp sync point will be usually 1.
3595 * For example, this corresponds to H.264 cpb_removal_delay.
3597 int dts_ref_dts_delta;
3600 * Presentation delay of current frame in units of AVCodecContext.time_base.
3602 * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
3603 * contain valid non-negative timestamp delta (presentation time of a frame
3604 * must not lie in the past).
3606 * This delay represents the difference between decoding and presentation
3607 * time of the frame.
3609 * For example, this corresponds to H.264 dpb_output_delay.
3614 * Position of the packet in file.
3616 * Analogous to cur_frame_pts/dts
3618 int64_t cur_frame_pos[AV_PARSER_PTS_NB];
3621 * Byte position of currently parsed frame in stream.
3626 * Previous frame byte position.
3629 } AVCodecParserContext;
3631 typedef struct AVCodecParser {
3632 int codec_ids[5]; /* several codec IDs are permitted */
3634 int (*parser_init)(AVCodecParserContext *s);
3635 int (*parser_parse)(AVCodecParserContext *s,
3636 AVCodecContext *avctx,
3637 const uint8_t **poutbuf, int *poutbuf_size,
3638 const uint8_t *buf, int buf_size);
3639 void (*parser_close)(AVCodecParserContext *s);
3640 int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
3641 struct AVCodecParser *next;
3644 AVCodecParser *av_parser_next(AVCodecParser *c);
3646 void av_register_codec_parser(AVCodecParser *parser);
3647 AVCodecParserContext *av_parser_init(int codec_id);
3649 #if LIBAVCODEC_VERSION_MAJOR < 53
3650 attribute_deprecated
3651 int av_parser_parse(AVCodecParserContext *s,
3652 AVCodecContext *avctx,
3653 uint8_t **poutbuf, int *poutbuf_size,
3654 const uint8_t *buf, int buf_size,
3655 int64_t pts, int64_t dts);
3661 * @param s parser context.
3662 * @param avctx codec context.
3663 * @param poutbuf set to pointer to parsed buffer or NULL if not yet finished.
3664 * @param poutbuf_size set to size of parsed buffer or zero if not yet finished.
3665 * @param buf input buffer.
3666 * @param buf_size input length, to signal EOF, this should be 0 (so that the last frame can be output).
3667 * @param pts input presentation timestamp.
3668 * @param dts input decoding timestamp.
3669 * @param pos input byte position in stream.
3670 * @return the number of bytes of the input bitstream used.
3675 * len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
3682 * decode_frame(data, size);
3686 int av_parser_parse2(AVCodecParserContext *s,
3687 AVCodecContext *avctx,
3688 uint8_t **poutbuf, int *poutbuf_size,
3689 const uint8_t *buf, int buf_size,
3690 int64_t pts, int64_t dts,
3693 int av_parser_change(AVCodecParserContext *s,
3694 AVCodecContext *avctx,
3695 uint8_t **poutbuf, int *poutbuf_size,
3696 const uint8_t *buf, int buf_size, int keyframe);
3697 void av_parser_close(AVCodecParserContext *s);
3700 typedef struct AVBitStreamFilterContext {
3702 struct AVBitStreamFilter *filter;
3703 AVCodecParserContext *parser;
3704 struct AVBitStreamFilterContext *next;
3705 } AVBitStreamFilterContext;
3708 typedef struct AVBitStreamFilter {
3711 int (*filter)(AVBitStreamFilterContext *bsfc,
3712 AVCodecContext *avctx, const char *args,
3713 uint8_t **poutbuf, int *poutbuf_size,
3714 const uint8_t *buf, int buf_size, int keyframe);
3715 void (*close)(AVBitStreamFilterContext *bsfc);
3716 struct AVBitStreamFilter *next;
3717 } AVBitStreamFilter;
3719 void av_register_bitstream_filter(AVBitStreamFilter *bsf);
3720 AVBitStreamFilterContext *av_bitstream_filter_init(const char *name);
3721 int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
3722 AVCodecContext *avctx, const char *args,
3723 uint8_t **poutbuf, int *poutbuf_size,
3724 const uint8_t *buf, int buf_size, int keyframe);
3725 void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);
3727 AVBitStreamFilter *av_bitstream_filter_next(AVBitStreamFilter *f);
3732 * Reallocates the given block if it is not large enough, otherwise it
3737 void *av_fast_realloc(void *ptr, unsigned int *size, unsigned int min_size);
3740 * Allocates a buffer, reusing the given one if large enough.
3742 * Contrary to av_fast_realloc the current buffer contents might not be
3743 * preserved and on error the old buffer is freed, thus no special
3744 * handling to avoid memleaks is necessary.
3746 * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
3747 * @param size size of the buffer *ptr points to
3748 * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
3749 * *size 0 if an error occurred.
3751 void av_fast_malloc(void *ptr, unsigned int *size, unsigned int min_size);
3754 * Copy image 'src' to 'dst'.
3756 void av_picture_copy(AVPicture *dst, const AVPicture *src,
3757 enum PixelFormat pix_fmt, int width, int height);
3760 * Crop image top and left side.
3762 int av_picture_crop(AVPicture *dst, const AVPicture *src,
3763 enum PixelFormat pix_fmt, int top_band, int left_band);
3768 int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width, enum PixelFormat pix_fmt,
3769 int padtop, int padbottom, int padleft, int padright, int *color);
3771 unsigned int av_xiphlacing(unsigned char *s, unsigned int v);
3774 * Parses str and put in width_ptr and height_ptr the detected values.
3776 * @return 0 in case of a successful parsing, a negative value otherwise
3777 * @param[in] str the string to parse: it has to be a string in the format
3778 * <width>x<height> or a valid video frame size abbreviation.
3779 * @param[in,out] width_ptr pointer to the variable which will contain the detected
3781 * @param[in,out] height_ptr pointer to the variable which will contain the detected
3782 * frame height value
3784 int av_parse_video_frame_size(int *width_ptr, int *height_ptr, const char *str);
3787 * Parses str and put in frame_rate the detected values.
3789 * @return 0 in case of a successful parsing, a negative value otherwise
3790 * @param[in] str the string to parse: it has to be a string in the format
3791 * <frame_rate_num>/<frame_rate_den>, a float number or a valid video rate abbreviation
3792 * @param[in,out] frame_rate pointer to the AVRational which will contain the detected
3795 int av_parse_video_frame_rate(AVRational *frame_rate, const char *str);
3797 /* error handling */
3799 #define AVERROR(e) (-(e)) /**< Returns a negative error code from a POSIX error code, to return from library functions. */
3800 #define AVUNERROR(e) (-(e)) /**< Returns a POSIX error code from a library function error return value. */
3802 /* Some platforms have E* and errno already negated. */
3803 #define AVERROR(e) (e)
3804 #define AVUNERROR(e) (e)
3806 #define AVERROR_UNKNOWN AVERROR(EINVAL) /**< unknown error */
3807 #define AVERROR_IO AVERROR(EIO) /**< I/O error */
3808 #define AVERROR_NUMEXPECTED AVERROR(EDOM) /**< Number syntax expected in filename. */
3809 #define AVERROR_INVALIDDATA AVERROR(EINVAL) /**< invalid data found */
3810 #define AVERROR_NOMEM AVERROR(ENOMEM) /**< not enough memory */
3811 #define AVERROR_NOFMT AVERROR(EILSEQ) /**< unknown format */
3812 #define AVERROR_NOTSUPP AVERROR(ENOSYS) /**< Operation not supported. */
3813 #define AVERROR_NOENT AVERROR(ENOENT) /**< No such file or directory. */
3814 #define AVERROR_EOF AVERROR(EPIPE) /**< End of file. */
3815 #define AVERROR_PATCHWELCOME -MKTAG('P','A','W','E') /**< Not yet implemented in FFmpeg. Patches welcome. */
3818 * Logs a generic warning message about a missing feature. This function is
3819 * intended to be used internally by FFmpeg (libavcodec, libavformat, etc.)
3820 * only, and would normally not be used by applications.
3821 * @param[in] avc a pointer to an arbitrary struct of which the first field is
3822 * a pointer to an AVClass struct
3823 * @param[in] feature string containing the name of the missing feature
3824 * @param[in] want_sample indicates if samples are wanted which exhibit this feature.
3825 * If want_sample is non-zero, additional verbage will be added to the log
3826 * message which tells the user how to report samples to the development
3829 void av_log_missing_feature(void *avc, const char *feature, int want_sample);
3832 * Logs a generic warning message asking for a sample. This function is
3833 * intended to be used internally by FFmpeg (libavcodec, libavformat, etc.)
3834 * only, and would normally not be used by applications.
3835 * @param[in] avc a pointer to an arbitrary struct of which the first field is
3836 * a pointer to an AVClass struct
3837 * @param[in] msg string containing an optional message, or NULL if no message
3839 void av_log_ask_for_sample(void *avc, const char *msg);
3842 * Registers the hardware accelerator hwaccel.
3844 void av_register_hwaccel(AVHWAccel *hwaccel);
3847 * If hwaccel is NULL, returns the first registered hardware accelerator,
3848 * if hwaccel is non-NULL, returns the next registered hardware accelerator
3849 * after hwaccel, or NULL if hwaccel is the last one.
3851 AVHWAccel *av_hwaccel_next(AVHWAccel *hwaccel);
3855 * Lock operation used by lockmgr
3858 AV_LOCK_CREATE, ///< Create a mutex
3859 AV_LOCK_OBTAIN, ///< Lock the mutex
3860 AV_LOCK_RELEASE, ///< Unlock the mutex
3861 AV_LOCK_DESTROY, ///< Free mutex resources
3865 * Register a user provided lock manager supporting the operations
3866 * specified by AVLockOp. mutex points to a (void *) where the
3867 * lockmgr should store/get a pointer to a user allocated mutex. It's
3868 * NULL upon AV_LOCK_CREATE and != NULL for all other ops.
3870 * @param cb User defined callback. Note: FFmpeg may invoke calls to this
3871 * callback during the call to av_lockmgr_register().
3872 * Thus, the application must be prepared to handle that.
3873 * If cb is set to NULL the lockmgr will be unregistered.
3874 * Also note that during unregistration the previously registered
3875 * lockmgr callback may also be invoked.
3877 int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op));
3879 #endif /* AVCODEC_AVCODEC_H */