1/*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of FFmpeg.
5 *
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.
10 *
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.
15 *
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
19 */
20
21#ifndef AVCODEC_AVCODEC_H
22#define AVCODEC_AVCODEC_H
23
24/**
25 * @file
26 * @ingroup libavc
27 * Libavcodec external API header
28 */
29
30#include "libavutil/samplefmt.h"
31#include "libavutil/attributes.h"
32#include "libavutil/avutil.h"
33#include "libavutil/buffer.h"
34#include "libavutil/channel_layout.h"
35#include "libavutil/dict.h"
36#include "libavutil/frame.h"
37#include "libavutil/log.h"
38#include "libavutil/pixfmt.h"
39#include "libavutil/rational.h"
40
41#include "codec.h"
42#include "codec_id.h"
43#include "defs.h"
44#include "packet.h"
45#include "version_major.h"
46#ifndef HAVE_AV_CONFIG_H
47/* When included as part of the ffmpeg build, only include the major version
48 * to avoid unnecessary rebuilds. When included externally, keep including
49 * the full version information. */
50#include "version.h"
51
52#include "codec_desc.h"
53#include "codec_par.h"
54#endif
55
56struct AVCodecParameters;
57
58/**
59 * @defgroup libavc libavcodec
60 * Encoding/Decoding Library
61 *
62 * @{
63 *
64 * @defgroup lavc_decoding Decoding
65 * @{
66 * @}
67 *
68 * @defgroup lavc_encoding Encoding
69 * @{
70 * @}
71 *
72 * @defgroup lavc_codec Codecs
73 * @{
74 * @defgroup lavc_codec_native Native Codecs
75 * @{
76 * @}
77 * @defgroup lavc_codec_wrappers External library wrappers
78 * @{
79 * @}
80 * @defgroup lavc_codec_hwaccel Hardware Accelerators bridge
81 * @{
82 * @}
83 * @}
84 * @defgroup lavc_internal Internal
85 * @{
86 * @}
87 * @}
88 */
89
90/**
91 * @ingroup libavc
92 * @defgroup lavc_encdec send/receive encoding and decoding API overview
93 * @{
94 *
95 * The avcodec_send_packet()/avcodec_receive_frame()/avcodec_send_frame()/
96 * avcodec_receive_packet() functions provide an encode/decode API, which
97 * decouples input and output.
98 *
99 * The API is very similar for encoding/decoding and audio/video, and works as
100 * follows:
101 * - Set up and open the AVCodecContext as usual.
102 * - Send valid input:
103 * - For decoding, call avcodec_send_packet() to give the decoder raw
104 * compressed data in an AVPacket.
105 * - For encoding, call avcodec_send_frame() to give the encoder an AVFrame
106 * containing uncompressed audio or video.
107 *
108 * In both cases, it is recommended that AVPackets and AVFrames are
109 * refcounted, or libavcodec might have to copy the input data. (libavformat
110 * always returns refcounted AVPackets, and av_frame_get_buffer() allocates
111 * refcounted AVFrames.)
112 * - Receive output in a loop. Periodically call one of the avcodec_receive_*()
113 * functions and process their output:
114 * - For decoding, call avcodec_receive_frame(). On success, it will return
115 * an AVFrame containing uncompressed audio or video data.
116 * - For encoding, call avcodec_receive_packet(). On success, it will return
117 * an AVPacket with a compressed frame.
118 *
119 * Repeat this call until it returns AVERROR(EAGAIN) or an error. The
120 * AVERROR(EAGAIN) return value means that new input data is required to
121 * return new output. In this case, continue with sending input. For each
122 * input frame/packet, the codec will typically return 1 output frame/packet,
123 * but it can also be 0 or more than 1.
124 *
125 * At the beginning of decoding or encoding, the codec might accept multiple
126 * input frames/packets without returning a frame, until its internal buffers
127 * are filled. This situation is handled transparently if you follow the steps
128 * outlined above.
129 *
130 * In theory, sending input can result in EAGAIN - this should happen only if
131 * not all output was received. You can use this to structure alternative decode
132 * or encode loops other than the one suggested above. For example, you could
133 * try sending new input on each iteration, and try to receive output if that
134 * returns EAGAIN.
135 *
136 * End of stream situations. These require "flushing" (aka draining) the codec,
137 * as the codec might buffer multiple frames or packets internally for
138 * performance or out of necessity (consider B-frames).
139 * This is handled as follows:
140 * - Instead of valid input, send NULL to the avcodec_send_packet() (decoding)
141 * or avcodec_send_frame() (encoding) functions. This will enter draining
142 * mode.
143 * - Call avcodec_receive_frame() (decoding) or avcodec_receive_packet()
144 * (encoding) in a loop until AVERROR_EOF is returned. The functions will
145 * not return AVERROR(EAGAIN), unless you forgot to enter draining mode.
146 * - Before decoding can be resumed again, the codec has to be reset with
147 * avcodec_flush_buffers().
148 *
149 * Using the API as outlined above is highly recommended. But it is also
150 * possible to call functions outside of this rigid schema. For example, you can
151 * call avcodec_send_packet() repeatedly without calling
152 * avcodec_receive_frame(). In this case, avcodec_send_packet() will succeed
153 * until the codec's internal buffer has been filled up (which is typically of
154 * size 1 per output frame, after initial input), and then reject input with
155 * AVERROR(EAGAIN). Once it starts rejecting input, you have no choice but to
156 * read at least some output.
157 *
158 * Not all codecs will follow a rigid and predictable dataflow; the only
159 * guarantee is that an AVERROR(EAGAIN) return value on a send/receive call on
160 * one end implies that a receive/send call on the other end will succeed, or
161 * at least will not fail with AVERROR(EAGAIN). In general, no codec will
162 * permit unlimited buffering of input or output.
163 *
164 * A codec is not allowed to return AVERROR(EAGAIN) for both sending and receiving. This
165 * would be an invalid state, which could put the codec user into an endless
166 * loop. The API has no concept of time either: it cannot happen that trying to
167 * do avcodec_send_packet() results in AVERROR(EAGAIN), but a repeated call 1 second
168 * later accepts the packet (with no other receive/flush API calls involved).
169 * The API is a strict state machine, and the passage of time is not supposed
170 * to influence it. Some timing-dependent behavior might still be deemed
171 * acceptable in certain cases. But it must never result in both send/receive
172 * returning EAGAIN at the same time at any point. It must also absolutely be
173 * avoided that the current state is "unstable" and can "flip-flop" between
174 * the send/receive APIs allowing progress. For example, it's not allowed that
175 * the codec randomly decides that it actually wants to consume a packet now
176 * instead of returning a frame, after it just returned AVERROR(EAGAIN) on an
177 * avcodec_send_packet() call.
178 * @}
179 */
180
181/**
182 * @defgroup lavc_core Core functions/structures.
183 * @ingroup libavc
184 *
185 * Basic definitions, functions for querying libavcodec capabilities,
186 * allocating core structures, etc.
187 * @{
188 */
189
190/**
191 * @ingroup lavc_encoding
192 */
193typedef struct RcOverride{
194 int start_frame;
195 int end_frame;
196 int qscale; // If this is 0 then quality_factor will be used instead.
197 float quality_factor;
198} RcOverride;
199
200/* encoding support
201 These flags can be passed in AVCodecContext.flags before initialization.
202 Note: Not everything is supported yet.
203*/
204
205/**
206 * Allow decoders to produce frames with data planes that are not aligned
207 * to CPU requirements (e.g. due to cropping).
208 */
209#define AV_CODEC_FLAG_UNALIGNED (1 << 0)
210/**
211 * Use fixed qscale.
212 */
213#define AV_CODEC_FLAG_QSCALE (1 << 1)
214/**
215 * 4 MV per MB allowed / advanced prediction for H.263.
216 */
217#define AV_CODEC_FLAG_4MV (1 << 2)
218/**
219 * Output even those frames that might be corrupted.
220 */
221#define AV_CODEC_FLAG_OUTPUT_CORRUPT (1 << 3)
222/**
223 * Use qpel MC.
224 */
225#define AV_CODEC_FLAG_QPEL (1 << 4)
226/**
227 * Request the encoder to output reconstructed frames, i.e.\ frames that would
228 * be produced by decoding the encoded bitstream. These frames may be retrieved
229 * by calling avcodec_receive_frame() immediately after a successful call to
230 * avcodec_receive_packet().
231 *
232 * Should only be used with encoders flagged with the
233 * @ref AV_CODEC_CAP_ENCODER_RECON_FRAME capability.
234 *
235 * @note
236 * Each reconstructed frame returned by the encoder corresponds to the last
237 * encoded packet, i.e. the frames are returned in coded order rather than
238 * presentation order.
239 *
240 * @note
241 * Frame parameters (like pixel format or dimensions) do not have to match the
242 * AVCodecContext values. Make sure to use the values from the returned frame.
243 */
244#define AV_CODEC_FLAG_RECON_FRAME (1 << 6)
245/**
246 * @par decoding
247 * Request the decoder to propagate each packet's AVPacket.opaque and
248 * AVPacket.opaque_ref to its corresponding output AVFrame.
249 *
250 * @par encoding:
251 * Request the encoder to propagate each frame's AVFrame.opaque and
252 * AVFrame.opaque_ref values to its corresponding output AVPacket.
253 *
254 * @par
255 * May only be set on encoders that have the
256 * @ref AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE capability flag.
257 *
258 * @note
259 * While in typical cases one input frame produces exactly one output packet
260 * (perhaps after a delay), in general the mapping of frames to packets is
261 * M-to-N, so
262 * - Any number of input frames may be associated with any given output packet.
263 * This includes zero - e.g. some encoders may output packets that carry only
264 * metadata about the whole stream.
265 * - A given input frame may be associated with any number of output packets.
266 * Again this includes zero - e.g. some encoders may drop frames under certain
267 * conditions.
268 * .
269 * This implies that when using this flag, the caller must NOT assume that
270 * - a given input frame's opaques will necessarily appear on some output packet;
271 * - every output packet will have some non-NULL opaque value.
272 * .
273 * When an output packet contains multiple frames, the opaque values will be
274 * taken from the first of those.
275 *
276 * @note
277 * The converse holds for decoders, with frames and packets switched.
278 */
279#define AV_CODEC_FLAG_COPY_OPAQUE (1 << 7)
280/**
281 * Signal to the encoder that the values of AVFrame.duration are valid and
282 * should be used (typically for transferring them to output packets).
283 *
284 * If this flag is not set, frame durations are ignored.
285 */
286#define AV_CODEC_FLAG_FRAME_DURATION (1 << 8)
287/**
288 * Use internal 2pass ratecontrol in first pass mode.
289 */
290#define AV_CODEC_FLAG_PASS1 (1 << 9)
291/**
292 * Use internal 2pass ratecontrol in second pass mode.
293 */
294#define AV_CODEC_FLAG_PASS2 (1 << 10)
295/**
296 * loop filter.
297 */
298#define AV_CODEC_FLAG_LOOP_FILTER (1 << 11)
299/**
300 * Only decode/encode grayscale.
301 */
302#define AV_CODEC_FLAG_GRAY (1 << 13)
303/**
304 * error[?] variables will be set during encoding.
305 */
306#define AV_CODEC_FLAG_PSNR (1 << 15)
307/**
308 * Use interlaced DCT.
309 */
310#define AV_CODEC_FLAG_INTERLACED_DCT (1 << 18)
311/**
312 * Force low delay.
313 */
314#define AV_CODEC_FLAG_LOW_DELAY (1 << 19)
315/**
316 * Place global headers in extradata instead of every keyframe.
317 */
318#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
319/**
320 * Use only bitexact stuff (except (I)DCT).
321 */
322#define AV_CODEC_FLAG_BITEXACT (1 << 23)
323/* Fx : Flag for H.263+ extra options */
324/**
325 * H.263 advanced intra coding / MPEG-4 AC prediction
326 */
327#define AV_CODEC_FLAG_AC_PRED (1 << 24)
328/**
329 * interlaced motion estimation
330 */
331#define AV_CODEC_FLAG_INTERLACED_ME (1 << 29)
332#define AV_CODEC_FLAG_CLOSED_GOP (1U << 31)
333
334/**
335 * Allow non spec compliant speedup tricks.
336 */
337#define AV_CODEC_FLAG2_FAST (1 << 0)
338/**
339 * Skip bitstream encoding.
340 */
341#define AV_CODEC_FLAG2_NO_OUTPUT (1 << 2)
342/**
343 * Place global headers at every keyframe instead of in extradata.
344 */
345#define AV_CODEC_FLAG2_LOCAL_HEADER (1 << 3)
346
347/**
348 * Input bitstream might be truncated at a packet boundaries
349 * instead of only at frame boundaries.
350 */
351#define AV_CODEC_FLAG2_CHUNKS (1 << 15)
352/**
353 * Discard cropping information from SPS.
354 */
355#define AV_CODEC_FLAG2_IGNORE_CROP (1 << 16)
356
357/**
358 * Show all frames before the first keyframe
359 */
360#define AV_CODEC_FLAG2_SHOW_ALL (1 << 22)
361/**
362 * Export motion vectors through frame side data
363 */
364#define AV_CODEC_FLAG2_EXPORT_MVS (1 << 28)
365/**
366 * Do not skip samples and export skip information as frame side data
367 */
368#define AV_CODEC_FLAG2_SKIP_MANUAL (1 << 29)
369/**
370 * Do not reset ASS ReadOrder field on flush (subtitles decoding)
371 */
372#define AV_CODEC_FLAG2_RO_FLUSH_NOOP (1 << 30)
373/**
374 * Generate/parse ICC profiles on encode/decode, as appropriate for the type of
375 * file. No effect on codecs which cannot contain embedded ICC profiles, or
376 * when compiled without support for lcms2.
377 */
378#define AV_CODEC_FLAG2_ICC_PROFILES (1U << 31)
379
380/* Exported side data.
381 These flags can be passed in AVCodecContext.export_side_data before initialization.
382*/
383/**
384 * Export motion vectors through frame side data
385 */
386#define AV_CODEC_EXPORT_DATA_MVS (1 << 0)
387/**
388 * Export encoder Producer Reference Time through packet side data
389 */
390#define AV_CODEC_EXPORT_DATA_PRFT (1 << 1)
391/**
392 * Decoding only.
393 * Export the AVVideoEncParams structure through frame side data.
394 */
395#define AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS (1 << 2)
396/**
397 * Decoding only.
398 * Do not apply film grain, export it instead.
399 */
400#define AV_CODEC_EXPORT_DATA_FILM_GRAIN (1 << 3)
401
402/**
403 * Decoding only.
404 * Do not apply picture enhancement layers, export them instead.
405 */
406#define AV_CODEC_EXPORT_DATA_ENHANCEMENTS (1 << 4)
407
408/**
409 * The decoder will keep a reference to the frame and may reuse it later.
410 */
411#define AV_GET_BUFFER_FLAG_REF (1 << 0)
412
413/**
414 * The encoder will keep a reference to the packet and may reuse it later.
415 */
416#define AV_GET_ENCODE_BUFFER_FLAG_REF (1 << 0)
417
418/**
419 * main external API structure.
420 * New fields can be added to the end with minor version bumps.
421 * Removal, reordering and changes to existing fields require a major
422 * version bump.
423 * You can use AVOptions (av_opt* / av_set/get*()) to access these fields from user
424 * applications.
425 * The name string for AVOptions options matches the associated command line
426 * parameter name and can be found in libavcodec/options_table.h
427 * The AVOption/command line parameter names differ in some cases from the C
428 * structure field names for historic reasons or brevity.
429 * sizeof(AVCodecContext) must not be used outside libav*.
430 */
431typedef struct AVCodecContext {
432 /**
433 * information on struct for av_log
434 * - set by avcodec_alloc_context3
435 */
436 const AVClass *av_class;
437 int log_level_offset;
438
439 enum AVMediaType codec_type; /* see AVMEDIA_TYPE_xxx */
440 const struct AVCodec *codec;
441 enum AVCodecID codec_id; /* see AV_CODEC_ID_xxx */
442
443 /**
444 * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
445 * This is used to work around some encoder bugs.
446 * A demuxer should set this to what is stored in the field used to identify the codec.
447 * If there are multiple such fields in a container then the demuxer should choose the one
448 * which maximizes the information about the used codec.
449 * If the codec tag field in a container is larger than 32 bits then the demuxer should
450 * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
451 * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
452 * first.
453 * - encoding: Set by user, if not then the default based on codec_id will be used.
454 * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
455 */
456 unsigned int codec_tag;
457
458 void *priv_data;
459
460 /**
461 * Private context used for internal data.
462 *
463 * Unlike priv_data, this is not codec-specific. It is used in general
464 * libavcodec functions.
465 */
466 struct AVCodecInternal *internal;
467
468 /**
469 * Private data of the user, can be used to carry app specific stuff.
470 * - encoding: Set by user.
471 * - decoding: Set by user.
472 */
473 void *opaque;
474
475 /**
476 * the average bitrate
477 * - encoding: Set by user; unused for constant quantizer encoding.
478 * - decoding: Set by user, may be overwritten by libavcodec
479 * if this info is available in the stream
480 */
481 int64_t bit_rate;
482
483 /**
484 * AV_CODEC_FLAG_*.
485 * - encoding: Set by user.
486 * - decoding: Set by user.
487 */
488 int flags;
489
490 /**
491 * AV_CODEC_FLAG2_*
492 * - encoding: Set by user.
493 * - decoding: Set by user.
494 */
495 int flags2;
496
497 /**
498 * Out-of-band global headers that may be used by some codecs.
499 *
500 * - decoding: Should be set by the caller when available (typically from a
501 * demuxer) before opening the decoder; some decoders require this to be
502 * set and will fail to initialize otherwise.
503 *
504 * The array must be allocated with the av_malloc() family of functions;
505 * allocated size must be at least AV_INPUT_BUFFER_PADDING_SIZE bytes
506 * larger than extradata_size.
507 *
508 * - encoding: May be set by the encoder in avcodec_open2() (possibly
509 * depending on whether the AV_CODEC_FLAG_GLOBAL_HEADER flag is set).
510 *
511 * After being set, the array is owned by the codec and freed in
512 * avcodec_free_context().
513 */
514 uint8_t *extradata;
515 int extradata_size;
516
517 /**
518 * This is the fundamental unit of time (in seconds) in terms
519 * of which frame timestamps are represented. For fixed-fps content,
520 * timebase should be 1/framerate and timestamp increments should be
521 * identically 1.
522 * This often, but not always is the inverse of the frame rate or field rate
523 * for video. 1/time_base is not the average frame rate if the frame rate is not
524 * constant.
525 *
526 * Like containers, elementary streams also can store timestamps, 1/time_base
527 * is the unit in which these timestamps are specified.
528 * As example of such codec time base see ISO/IEC 14496-2:2001(E)
529 * vop_time_increment_resolution and fixed_vop_rate
530 * (fixed_vop_rate == 0 implies that it is different from the framerate)
531 *
532 * - encoding: MUST be set by user.
533 * - decoding: unused.
534 */
535 AVRational time_base;
536
537 /**
538 * Timebase in which pkt_dts/pts and AVPacket.dts/pts are expressed.
539 * - encoding: unused.
540 * - decoding: set by user.
541 */
542 AVRational pkt_timebase;
543
544 /**
545 * - decoding: For codecs that store a framerate value in the compressed
546 * bitstream, the decoder may export it here. { 0, 1} when
547 * unknown.
548 * - encoding: May be used to signal the framerate of CFR content to an
549 * encoder.
550 */
551 AVRational framerate;
552
553 /**
554 * Codec delay.
555 *
556 * Encoding: Number of frames delay there will be from the encoder input to
557 * the decoder output. (we assume the decoder matches the spec)
558 * Decoding: Number of frames delay in addition to what a standard decoder
559 * as specified in the spec would produce.
560 *
561 * Video:
562 * Number of frames the decoded output will be delayed relative to the
563 * encoded input.
564 *
565 * Audio:
566 * For encoding, this field is unused (see initial_padding).
567 *
568 * For decoding, this is the number of samples the decoder needs to
569 * output before the decoder's output is valid. When seeking, you should
570 * start decoding this many samples prior to your desired seek point.
571 *
572 * - encoding: Set by libavcodec.
573 * - decoding: Set by libavcodec.
574 */
575 int delay;
576
577
578 /* video only */
579 /**
580 * picture width / height.
581 *
582 * @note Those fields may not match the values of the last
583 * AVFrame output by avcodec_receive_frame() due frame
584 * reordering.
585 *
586 * - encoding: MUST be set by user.
587 * - decoding: May be set by the user before opening the decoder if known e.g.
588 * from the container. Some decoders will require the dimensions
589 * to be set by the caller. During decoding, the decoder may
590 * overwrite those values as required while parsing the data.
591 */
592 int width, height;
593
594 /**
595 * Bitstream width / height, may be different from width/height e.g. when
596 * the decoded frame is cropped before being output or lowres is enabled.
597 *
598 * @note Those field may not match the value of the last
599 * AVFrame output by avcodec_receive_frame() due frame
600 * reordering.
601 *
602 * - encoding: unused
603 * - decoding: May be set by the user before opening the decoder if known
604 * e.g. from the container. During decoding, the decoder may
605 * overwrite those values as required while parsing the data.
606 */
607 int coded_width, coded_height;
608
609 /**
610 * sample aspect ratio (0 if unknown)
611 * That is the width of a pixel divided by the height of the pixel.
612 * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
613 * - encoding: Set by user.
614 * - decoding: Set by libavcodec.
615 */
616 AVRational sample_aspect_ratio;
617
618 /**
619 * Pixel format, see AV_PIX_FMT_xxx.
620 * May be set by the demuxer if known from headers.
621 * May be overridden by the decoder if it knows better.
622 *
623 * @note This field may not match the value of the last
624 * AVFrame output by avcodec_receive_frame() due frame
625 * reordering.
626 *
627 * - encoding: Set by user.
628 * - decoding: Set by user if known, overridden by libavcodec while
629 * parsing the data.
630 */
631 enum AVPixelFormat pix_fmt;
632
633 /**
634 * Nominal unaccelerated pixel format, see AV_PIX_FMT_xxx.
635 * - encoding: unused.
636 * - decoding: Set by libavcodec before calling get_format()
637 */
638 enum AVPixelFormat sw_pix_fmt;
639
640 /**
641 * Chromaticity coordinates of the source primaries.
642 * - encoding: Set by user
643 * - decoding: Set by libavcodec
644 */
645 enum AVColorPrimaries color_primaries;
646
647 /**
648 * Color Transfer Characteristic.
649 * - encoding: Set by user
650 * - decoding: Set by libavcodec
651 */
652 enum AVColorTransferCharacteristic color_trc;
653
654 /**
655 * YUV colorspace type.
656 * - encoding: Set by user
657 * - decoding: Set by libavcodec
658 */
659 enum AVColorSpace colorspace;
660
661 /**
662 * MPEG vs JPEG YUV range.
663 * - encoding: Set by user to override the default output color range value,
664 * If not specified, libavcodec sets the color range depending on the
665 * output format.
666 * - decoding: Set by libavcodec, can be set by the user to propagate the
667 * color range to components reading from the decoder context.
668 */
669 enum AVColorRange color_range;
670
671 /**
672 * This defines the location of chroma samples.
673 * - encoding: Set by user
674 * - decoding: Set by libavcodec
675 */
676 enum AVChromaLocation chroma_sample_location;
677
678 /** Field order
679 * - encoding: set by libavcodec
680 * - decoding: Set by user.
681 */
682 enum AVFieldOrder field_order;
683
684 /**
685 * number of reference frames
686 * - encoding: Set by user.
687 * - decoding: Set by lavc.
688 */
689 int refs;
690
691 /**
692 * Size of the frame reordering buffer in the decoder.
693 * For MPEG-2 it is 1 IPB or 0 low delay IP.
694 * - encoding: Set by libavcodec.
695 * - decoding: Set by libavcodec.
696 */
697 int has_b_frames;
698
699 /**
700 * slice flags
701 * - encoding: unused
702 * - decoding: Set by user.
703 */
704 int slice_flags;
705#define SLICE_FLAG_CODED_ORDER 0x0001 ///< draw_horiz_band() is called in coded order instead of display
706#define SLICE_FLAG_ALLOW_FIELD 0x0002 ///< allow draw_horiz_band() with field slices (MPEG-2 field pics)
707#define SLICE_FLAG_ALLOW_PLANE 0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)
708
709 /**
710 * If non NULL, 'draw_horiz_band' is called by the libavcodec
711 * decoder to draw a horizontal band. It improves cache usage. Not
712 * all codecs can do that. You must check the codec capabilities
713 * beforehand.
714 * When multithreading is used, it may be called from multiple threads
715 * at the same time; threads might draw different parts of the same AVFrame,
716 * or multiple AVFrames, and there is no guarantee that slices will be drawn
717 * in order.
718 * The function is also used by hardware acceleration APIs.
719 * It is called at least once during frame decoding to pass
720 * the data needed for hardware render.
721 * In that mode instead of pixel data, AVFrame points to
722 * a structure specific to the acceleration API. The application
723 * reads the structure and can change some fields to indicate progress
724 * or mark state.
725 * - encoding: unused
726 * - decoding: Set by user.
727 * @param height the height of the slice
728 * @param y the y position of the slice
729 * @param type 1->top field, 2->bottom field, 3->frame
730 * @param offset offset into the AVFrame.data from which the slice should be read
731 */
732 void (*draw_horiz_band)(struct AVCodecContext *s,
733 const AVFrame *src, int offset[AV_NUM_DATA_POINTERS],
734 int y, int type, int height);
735
736 /**
737 * Callback to negotiate the pixel format. Decoding only, may be set by the
738 * caller before avcodec_open2().
739 *
740 * Called by some decoders to select the pixel format that will be used for
741 * the output frames. This is mainly used to set up hardware acceleration,
742 * then the provided format list contains the corresponding hwaccel pixel
743 * formats alongside the "software" one. The software pixel format may also
744 * be retrieved from \ref sw_pix_fmt.
745 *
746 * This callback will be called when the coded frame properties (such as
747 * resolution, pixel format, etc.) change and more than one output format is
748 * supported for those new properties. If a hardware pixel format is chosen
749 * and initialization for it fails, the callback may be called again
750 * immediately.
751 *
752 * This callback may be called from different threads if the decoder is
753 * multi-threaded, but not from more than one thread simultaneously.
754 *
755 * @param fmt list of formats which may be used in the current
756 * configuration, terminated by AV_PIX_FMT_NONE.
757 * @warning Behavior is undefined if the callback returns a value other
758 * than one of the formats in fmt or AV_PIX_FMT_NONE.
759 * @return the chosen format or AV_PIX_FMT_NONE
760 */
761 enum AVPixelFormat (*get_format)(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
762
763 /**
764 * maximum number of B-frames between non-B-frames
765 * Note: The output will be delayed by max_b_frames+1 relative to the input.
766 * - encoding: Set by user.
767 * - decoding: unused
768 */
769 int max_b_frames;
770
771 /**
772 * qscale factor between IP and B-frames
773 * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
774 * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
775 * - encoding: Set by user.
776 * - decoding: unused
777 */
778 float b_quant_factor;
779
780 /**
781 * qscale offset between IP and B-frames
782 * - encoding: Set by user.
783 * - decoding: unused
784 */
785 float b_quant_offset;
786
787 /**
788 * qscale factor between P- and I-frames
789 * If > 0 then the last P-frame quantizer will be used (q = lastp_q * factor + offset).
790 * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
791 * - encoding: Set by user.
792 * - decoding: unused
793 */
794 float i_quant_factor;
795
796 /**
797 * qscale offset between P and I-frames
798 * - encoding: Set by user.
799 * - decoding: unused
800 */
801 float i_quant_offset;
802
803 /**
804 * luminance masking (0-> disabled)
805 * - encoding: Set by user.
806 * - decoding: unused
807 */
808 float lumi_masking;
809
810 /**
811 * temporary complexity masking (0-> disabled)
812 * - encoding: Set by user.
813 * - decoding: unused
814 */
815 float temporal_cplx_masking;
816
817 /**
818 * spatial complexity masking (0-> disabled)
819 * - encoding: Set by user.
820 * - decoding: unused
821 */
822 float spatial_cplx_masking;
823
824 /**
825 * p block masking (0-> disabled)
826 * - encoding: Set by user.
827 * - decoding: unused
828 */
829 float p_masking;
830
831 /**
832 * darkness masking (0-> disabled)
833 * - encoding: Set by user.
834 * - decoding: unused
835 */
836 float dark_masking;
837
838 /**
839 * noise vs. sse weight for the nsse comparison function
840 * - encoding: Set by user.
841 * - decoding: unused
842 */
843 int nsse_weight;
844
845 /**
846 * motion estimation comparison function
847 * - encoding: Set by user.
848 * - decoding: unused
849 */
850 int me_cmp;
851 /**
852 * subpixel motion estimation comparison function
853 * - encoding: Set by user.
854 * - decoding: unused
855 */
856 int me_sub_cmp;
857 /**
858 * macroblock comparison function (not supported yet)
859 * - encoding: Set by user.
860 * - decoding: unused
861 */
862 int mb_cmp;
863 /**
864 * interlaced DCT comparison function
865 * - encoding: Set by user.
866 * - decoding: unused
867 */
868 int ildct_cmp;
869#define FF_CMP_SAD 0
870#define FF_CMP_SSE 1
871#define FF_CMP_SATD 2
872#define FF_CMP_DCT 3
873#define FF_CMP_PSNR 4
874#define FF_CMP_BIT 5
875#define FF_CMP_RD 6
876#define FF_CMP_ZERO 7
877#define FF_CMP_VSAD 8
878#define FF_CMP_VSSE 9
879#define FF_CMP_NSSE 10
880#define FF_CMP_W53 11
881#define FF_CMP_W97 12
882#define FF_CMP_DCTMAX 13
883#define FF_CMP_DCT264 14
884#define FF_CMP_MEDIAN_SAD 15
885#define FF_CMP_CHROMA 256
886
887 /**
888 * ME diamond size & shape
889 * - encoding: Set by user.
890 * - decoding: unused
891 */
892 int dia_size;
893
894 /**
895 * amount of previous MV predictors (2a+1 x 2a+1 square)
896 * - encoding: Set by user.
897 * - decoding: unused
898 */
899 int last_predictor_count;
900
901 /**
902 * motion estimation prepass comparison function
903 * - encoding: Set by user.
904 * - decoding: unused
905 */
906 int me_pre_cmp;
907
908 /**
909 * ME prepass diamond size & shape
910 * - encoding: Set by user.
911 * - decoding: unused
912 */
913 int pre_dia_size;
914
915 /**
916 * subpel ME quality
917 * - encoding: Set by user.
918 * - decoding: unused
919 */
920 int me_subpel_quality;
921
922 /**
923 * maximum motion estimation search range in subpel units
924 * If 0 then no limit.
925 *
926 * - encoding: Set by user.
927 * - decoding: unused
928 */
929 int me_range;
930
931 /**
932 * macroblock decision mode
933 * - encoding: Set by user.
934 * - decoding: unused
935 */
936 int mb_decision;
937#define FF_MB_DECISION_SIMPLE 0 ///< uses mb_cmp
938#define FF_MB_DECISION_BITS 1 ///< chooses the one which needs the fewest bits
939#define FF_MB_DECISION_RD 2 ///< rate distortion
940
941 /**
942 * custom intra quantization matrix
943 * Must be allocated with the av_malloc() family of functions, and will be freed in
944 * avcodec_free_context().
945 * - encoding: Set/allocated by user, freed by libavcodec. Can be NULL.
946 * - decoding: Set/allocated/freed by libavcodec.
947 */
948 uint16_t *intra_matrix;
949
950 /**
951 * custom inter quantization matrix
952 * Must be allocated with the av_malloc() family of functions, and will be freed in
953 * avcodec_free_context().
954 * - encoding: Set/allocated by user, freed by libavcodec. Can be NULL.
955 * - decoding: Set/allocated/freed by libavcodec.
956 */
957 uint16_t *inter_matrix;
958
959 /**
960 * custom intra quantization matrix
961 * - encoding: Set by user, can be NULL.
962 * - decoding: unused.
963 */
964 uint16_t *chroma_intra_matrix;
965
966 /**
967 * precision of the intra DC coefficient - 8
968 * - encoding: Set by user.
969 * - decoding: Set by libavcodec
970 */
971 int intra_dc_precision;
972
973 /**
974 * minimum MB Lagrange multiplier
975 * - encoding: Set by user.
976 * - decoding: unused
977 */
978 int mb_lmin;
979
980 /**
981 * maximum MB Lagrange multiplier
982 * - encoding: Set by user.
983 * - decoding: unused
984 */
985 int mb_lmax;
986
987 /**
988 * - encoding: Set by user.
989 * - decoding: unused
990 */
991 int bidir_refine;
992
993 /**
994 * minimum GOP size
995 * - encoding: Set by user.
996 * - decoding: unused
997 */
998 int keyint_min;
999
1000 /**
1001 * the number of pictures in a group of pictures, or 0 for intra_only
1002 * - encoding: Set by user.
1003 * - decoding: unused
1004 */
1005 int gop_size;
1006
1007 /**
1008 * Note: Value depends upon the compare function used for fullpel ME.
1009 * - encoding: Set by user.
1010 * - decoding: unused
1011 */
1012 int mv0_threshold;
1013
1014 /**
1015 * Number of slices.
1016 * Indicates number of picture subdivisions. Used for parallelized
1017 * decoding.
1018 * - encoding: Set by user
1019 * - decoding: unused
1020 */
1021 int slices;
1022
1023 /* audio only */
1024 int sample_rate; ///< samples per second
1025
1026 /**
1027 * audio sample format
1028 * - encoding: Set by user.
1029 * - decoding: Set by libavcodec.
1030 */
1031 enum AVSampleFormat sample_fmt; ///< sample format
1032
1033 /**
1034 * Audio channel layout.
1035 * - encoding: must be set by the caller, to one of AVCodec.ch_layouts.
1036 * - decoding: may be set by the caller if known e.g. from the container.
1037 * The decoder can then override during decoding as needed.
1038 */
1039 AVChannelLayout ch_layout;
1040
1041 /* The following data should not be initialized. */
1042 /**
1043 * Number of samples per channel in an audio frame.
1044 *
1045 * - encoding: set by libavcodec in avcodec_open2(). Each submitted frame
1046 * except the last must contain exactly frame_size samples per channel.
1047 * May be 0 when the codec has AV_CODEC_CAP_VARIABLE_FRAME_SIZE set, then the
1048 * frame size is not restricted.
1049 * - decoding: may be set by some decoders to indicate constant frame size
1050 */
1051 int frame_size;
1052
1053 /**
1054 * number of bytes per packet if constant and known or 0
1055 * Used by some WAV based audio codecs.
1056 */
1057 int block_align;
1058
1059 /**
1060 * Audio cutoff bandwidth (0 means "automatic")
1061 * - encoding: Set by user.
1062 * - decoding: unused
1063 */
1064 int cutoff;
1065
1066 /**
1067 * Type of service that the audio stream conveys.
1068 * - encoding: Set by user.
1069 * - decoding: Set by libavcodec.
1070 */
1071 enum AVAudioServiceType audio_service_type;
1072
1073 /**
1074 * desired sample format
1075 * - encoding: Not used.
1076 * - decoding: Set by user.
1077 * Decoder will decode to this format if it can.
1078 */
1079 enum AVSampleFormat request_sample_fmt;
1080
1081 /**
1082 * Audio only. The number of "priming" samples (padding) inserted by the
1083 * encoder at the beginning of the audio. I.e. this number of leading
1084 * decoded samples must be discarded by the caller to get the original audio
1085 * without leading padding.
1086 *
1087 * - decoding: unused
1088 * - encoding: Set by libavcodec. The timestamps on the output packets are
1089 * adjusted by the encoder so that they always refer to the
1090 * first sample of the data actually contained in the packet,
1091 * including any added padding. E.g. if the timebase is
1092 * 1/samplerate and the timestamp of the first input sample is
1093 * 0, the timestamp of the first output packet will be
1094 * -initial_padding.
1095 */
1096 int initial_padding;
1097
1098 /**
1099 * Audio only. The amount of padding (in samples) appended by the encoder to
1100 * the end of the audio. I.e. this number of decoded samples must be
1101 * discarded by the caller from the end of the stream to get the original
1102 * audio without any trailing padding.
1103 *
1104 * - decoding: unused
1105 * - encoding: unused
1106 */
1107 int trailing_padding;
1108
1109 /**
1110 * Number of samples to skip after a discontinuity
1111 * - decoding: unused
1112 * - encoding: set by libavcodec
1113 */
1114 int seek_preroll;
1115
1116 /**
1117 * This callback is called at the beginning of each frame to get data
1118 * buffer(s) for it. There may be one contiguous buffer for all the data or
1119 * there may be a buffer per each data plane or anything in between. What
1120 * this means is, you may set however many entries in buf[] you feel necessary.
1121 * Each buffer must be reference-counted using the AVBuffer API (see description
1122 * of buf[] below).
1123 *
1124 * The following fields will be set in the frame before this callback is
1125 * called:
1126 * - format
1127 * - width, height (video only)
1128 * - sample_rate, channel_layout, nb_samples (audio only)
1129 * Their values may differ from the corresponding values in
1130 * AVCodecContext. This callback must use the frame values, not the codec
1131 * context values, to calculate the required buffer size.
1132 *
1133 * This callback must fill the following fields in the frame:
1134 * - data[]
1135 * - linesize[]
1136 * - extended_data:
1137 * * if the data is planar audio with more than 8 channels, then this
1138 * callback must allocate and fill extended_data to contain all pointers
1139 * to all data planes. data[] must hold as many pointers as it can.
1140 * extended_data must be allocated with av_malloc() and will be freed in
1141 * av_frame_unref().
1142 * * otherwise extended_data must point to data
1143 * - buf[] must contain one or more pointers to AVBufferRef structures. Each of
1144 * the frame's data and extended_data pointers must be contained in these. That
1145 * is, one AVBufferRef for each allocated chunk of memory, not necessarily one
1146 * AVBufferRef per data[] entry. See: av_buffer_create(), av_buffer_alloc(),
1147 * and av_buffer_ref().
1148 * - extended_buf and nb_extended_buf must be allocated with av_malloc() by
1149 * this callback and filled with the extra buffers if there are more
1150 * buffers than buf[] can hold. extended_buf will be freed in
1151 * av_frame_unref().
1152 * Decoders will generally initialize the whole buffer before it is output
1153 * but it can in rare error conditions happen that uninitialized data is passed
1154 * through. \important The buffers returned by get_buffer* should thus not contain sensitive
1155 * data.
1156 *
1157 * If AV_CODEC_CAP_DR1 is not set then get_buffer2() must call
1158 * avcodec_default_get_buffer2() instead of providing buffers allocated by
1159 * some other means.
1160 *
1161 * Each data plane must be aligned to the maximum required by the target
1162 * CPU.
1163 *
1164 * @see avcodec_default_get_buffer2()
1165 *
1166 * Video:
1167 *
1168 * If AV_GET_BUFFER_FLAG_REF is set in flags then the frame may be reused
1169 * (read and/or written to if it is writable) later by libavcodec.
1170 *
1171 * avcodec_align_dimensions2() should be used to find the required width and
1172 * height, as they normally need to be rounded up to the next multiple of 16.
1173 *
1174 * Some decoders do not support linesizes changing between frames.
1175 *
1176 * If frame multithreading is used, this callback may be called from a
1177 * different thread, but not from more than one at once. Does not need to be
1178 * reentrant.
1179 *
1180 * @see avcodec_align_dimensions2()
1181 *
1182 * Audio:
1183 *
1184 * Decoders request a buffer of a particular size by setting
1185 * AVFrame.nb_samples prior to calling get_buffer2(). The decoder may,
1186 * however, utilize only part of the buffer by setting AVFrame.nb_samples
1187 * to a smaller value in the output frame.
1188 *
1189 * As a convenience, av_samples_get_buffer_size() and
1190 * av_samples_fill_arrays() in libavutil may be used by custom get_buffer2()
1191 * functions to find the required data size and to fill data pointers and
1192 * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
1193 * since all planes must be the same size.
1194 *
1195 * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
1196 *
1197 * - encoding: unused
1198 * - decoding: Set by libavcodec, user can override.
1199 */
1200 int (*get_buffer2)(struct AVCodecContext *s, AVFrame *frame, int flags);
1201
1202 /* - encoding parameters */
1203 /**
1204 * number of bits the bitstream is allowed to diverge from the reference.
1205 * the reference can be CBR (for CBR pass1) or VBR (for pass2)
1206 * - encoding: Set by user; unused for constant quantizer encoding.
1207 * - decoding: unused
1208 */
1209 int bit_rate_tolerance;
1210
1211 /**
1212 * Global quality for codecs which cannot change it per frame.
1213 * This should be proportional to MPEG-1/2/4 qscale.
1214 * - encoding: Set by user.
1215 * - decoding: unused
1216 */
1217 int global_quality;
1218
1219 /**
1220 * - encoding: Set by user.
1221 * - decoding: unused
1222 */
1223 int compression_level;
1224#define FF_COMPRESSION_DEFAULT -1
1225
1226 float qcompress; ///< amount of qscale change between easy & hard scenes (0.0-1.0)
1227 float qblur; ///< amount of qscale smoothing over time (0.0-1.0)
1228
1229 /**
1230 * minimum quantizer
1231 * - encoding: Set by user.
1232 * - decoding: unused
1233 */
1234 int qmin;
1235
1236 /**
1237 * maximum quantizer
1238 * - encoding: Set by user.
1239 * - decoding: unused
1240 */
1241 int qmax;
1242
1243 /**
1244 * maximum quantizer difference between frames
1245 * - encoding: Set by user.
1246 * - decoding: unused
1247 */
1248 int max_qdiff;
1249
1250 /**
1251 * decoder bitstream buffer size
1252 * - encoding: Set by user.
1253 * - decoding: May be set by libavcodec.
1254 */
1255 int rc_buffer_size;
1256
1257 /**
1258 * ratecontrol override, see RcOverride
1259 * - encoding: Allocated/set/freed by user.
1260 * - decoding: unused
1261 */
1262 int rc_override_count;
1263 RcOverride *rc_override;
1264
1265 /**
1266 * maximum bitrate
1267 * - encoding: Set by user.
1268 * - decoding: Set by user, may be overwritten by libavcodec.
1269 */
1270 int64_t rc_max_rate;
1271
1272 /**
1273 * minimum bitrate
1274 * - encoding: Set by user.
1275 * - decoding: unused
1276 */
1277 int64_t rc_min_rate;
1278
1279 /**
1280 * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
1281 * - encoding: Set by user.
1282 * - decoding: unused.
1283 */
1284 float rc_max_available_vbv_use;
1285
1286 /**
1287 * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
1288 * - encoding: Set by user.
1289 * - decoding: unused.
1290 */
1291 float rc_min_vbv_overflow_use;
1292
1293 /**
1294 * Number of bits which should be loaded into the rc buffer before decoding starts.
1295 * - encoding: Set by user.
1296 * - decoding: unused
1297 */
1298 int rc_initial_buffer_occupancy;
1299
1300 /**
1301 * trellis RD quantization
1302 * - encoding: Set by user.
1303 * - decoding: unused
1304 */
1305 int trellis;
1306
1307 /**
1308 * pass1 encoding statistics output buffer
1309 * - encoding: Set by libavcodec.
1310 * - decoding: unused
1311 */
1312 char *stats_out;
1313
1314 /**
1315 * pass2 encoding statistics input buffer
1316 * Concatenated stuff from stats_out of pass1 should be placed here.
1317 * - encoding: Allocated/set/freed by user.
1318 * - decoding: unused
1319 */
1320 char *stats_in;
1321
1322 /**
1323 * Work around bugs in encoders which sometimes cannot be detected automatically.
1324 * - encoding: Set by user
1325 * - decoding: Set by user
1326 */
1327 int workaround_bugs;
1328#define FF_BUG_AUTODETECT 1 ///< autodetection
1329#define FF_BUG_XVID_ILACE 4
1330#define FF_BUG_UMP4 8
1331#define FF_BUG_NO_PADDING 16
1332#define FF_BUG_AMV 32
1333#define FF_BUG_QPEL_CHROMA 64
1334#define FF_BUG_STD_QPEL 128
1335#define FF_BUG_QPEL_CHROMA2 256
1336#define FF_BUG_DIRECT_BLOCKSIZE 512
1337#define FF_BUG_EDGE 1024
1338#define FF_BUG_HPEL_CHROMA 2048
1339#define FF_BUG_DC_CLIP 4096
1340#define FF_BUG_MS 8192 ///< Work around various bugs in Microsoft's broken decoders.
1341#define FF_BUG_TRUNCATED 16384
1342#define FF_BUG_IEDGE 32768
1343
1344 /**
1345 * strictly follow the standard (MPEG-4, ...).
1346 * - encoding: Set by user.
1347 * - decoding: Set by user.
1348 * Setting this to STRICT or higher means the encoder and decoder will
1349 * generally do stupid things, whereas setting it to unofficial or lower
1350 * will mean the encoder might produce output that is not supported by all
1351 * spec-compliant decoders. Decoders don't differentiate between normal,
1352 * unofficial and experimental (that is, they always try to decode things
1353 * when they can) unless they are explicitly asked to behave stupidly
1354 * (=strictly conform to the specs)
1355 * This may only be set to one of the FF_COMPLIANCE_* values in defs.h.
1356 */
1357 int strict_std_compliance;
1358
1359 /**
1360 * error concealment flags
1361 * - encoding: unused
1362 * - decoding: Set by user.
1363 */
1364 int error_concealment;
1365#define FF_EC_GUESS_MVS 1
1366#define FF_EC_DEBLOCK 2
1367#define FF_EC_FAVOR_INTER 256
1368
1369 /**
1370 * debug
1371 * - encoding: Set by user.
1372 * - decoding: Set by user.
1373 */
1374 int debug;
1375#define FF_DEBUG_PICT_INFO 1
1376#define FF_DEBUG_RC 2
1377#define FF_DEBUG_BITSTREAM 4
1378#define FF_DEBUG_MB_TYPE 8
1379#define FF_DEBUG_QP 16
1380#define FF_DEBUG_DCT_COEFF 0x00000040
1381#define FF_DEBUG_SKIP 0x00000080
1382#define FF_DEBUG_STARTCODE 0x00000100
1383#define FF_DEBUG_ER 0x00000400
1384#define FF_DEBUG_MMCO 0x00000800
1385#define FF_DEBUG_BUGS 0x00001000
1386#define FF_DEBUG_BUFFERS 0x00008000
1387#define FF_DEBUG_THREADS 0x00010000
1388#define FF_DEBUG_GREEN_MD 0x00800000
1389#define FF_DEBUG_NOMC 0x01000000
1390
1391 /**
1392 * Error recognition; may misdetect some more or less valid parts as errors.
1393 * This is a bitfield of the AV_EF_* values defined in defs.h.
1394 *
1395 * - encoding: Set by user.
1396 * - decoding: Set by user.
1397 */
1398 int err_recognition;
1399
1400 /**
1401 * Hardware accelerator in use
1402 * - encoding: unused.
1403 * - decoding: Set by libavcodec
1404 */
1405 const struct AVHWAccel *hwaccel;
1406
1407 /**
1408 * Legacy hardware accelerator context.
1409 *
1410 * For some hardware acceleration methods, the caller may use this field to
1411 * signal hwaccel-specific data to the codec. The struct pointed to by this
1412 * pointer is hwaccel-dependent and defined in the respective header. Please
1413 * refer to the FFmpeg HW accelerator documentation to know how to fill
1414 * this.
1415 *
1416 * In most cases this field is optional - the necessary information may also
1417 * be provided to libavcodec through @ref hw_frames_ctx or @ref
1418 * hw_device_ctx (see avcodec_get_hw_config()). However, in some cases it
1419 * may be the only method of signalling some (optional) information.
1420 *
1421 * The struct and its contents are owned by the caller.
1422 *
1423 * - encoding: May be set by the caller before avcodec_open2(). Must remain
1424 * valid until avcodec_free_context().
1425 * - decoding: May be set by the caller in the get_format() callback.
1426 * Must remain valid until the next get_format() call,
1427 * or avcodec_free_context() (whichever comes first).
1428 */
1429 void *hwaccel_context;
1430
1431 /**
1432 * A reference to the AVHWFramesContext describing the input (for encoding)
1433 * or output (decoding) frames. The reference is set by the caller and
1434 * afterwards owned (and freed) by libavcodec - it should never be read by
1435 * the caller after being set.
1436 *
1437 * - decoding: This field should be set by the caller from the get_format()
1438 * callback. The previous reference (if any) will always be
1439 * unreffed by libavcodec before the get_format() call.
1440 *
1441 * If the default get_buffer2() is used with a hwaccel pixel
1442 * format, then this AVHWFramesContext will be used for
1443 * allocating the frame buffers.
1444 *
1445 * - encoding: For hardware encoders configured to use a hwaccel pixel
1446 * format, this field should be set by the caller to a reference
1447 * to the AVHWFramesContext describing input frames.
1448 * AVHWFramesContext.format must be equal to
1449 * AVCodecContext.pix_fmt.
1450 *
1451 * This field should be set before avcodec_open2() is called.
1452 */
1453 AVBufferRef *hw_frames_ctx;
1454
1455 /**
1456 * A reference to the AVHWDeviceContext describing the device which will
1457 * be used by a hardware encoder/decoder. The reference is set by the
1458 * caller and afterwards owned (and freed) by libavcodec.
1459 *
1460 * This should be used if either the codec device does not require
1461 * hardware frames or any that are used are to be allocated internally by
1462 * libavcodec. If the user wishes to supply any of the frames used as
1463 * encoder input or decoder output then hw_frames_ctx should be used
1464 * instead. When hw_frames_ctx is set in get_format() for a decoder, this
1465 * field will be ignored while decoding the associated stream segment, but
1466 * may again be used on a following one after another get_format() call.
1467 *
1468 * For both encoders and decoders this field should be set before
1469 * avcodec_open2() is called and must not be written to thereafter.
1470 *
1471 * Note that some decoders may require this field to be set initially in
1472 * order to support hw_frames_ctx at all - in that case, all frames
1473 * contexts used must be created on the same device.
1474 */
1475 AVBufferRef *hw_device_ctx;
1476
1477 /**
1478 * Bit set of AV_HWACCEL_FLAG_* flags, which affect hardware accelerated
1479 * decoding (if active).
1480 * - encoding: unused
1481 * - decoding: Set by user (either before avcodec_open2(), or in the
1482 * AVCodecContext.get_format callback)
1483 */
1484 int hwaccel_flags;
1485
1486 /**
1487 * Video decoding only. Sets the number of extra hardware frames which
1488 * the decoder will allocate for use by the caller. This must be set
1489 * before avcodec_open2() is called.
1490 *
1491 * Some hardware decoders require all frames that they will use for
1492 * output to be defined in advance before decoding starts. For such
1493 * decoders, the hardware frame pool must therefore be of a fixed size.
1494 * The extra frames set here are on top of any number that the decoder
1495 * needs internally in order to operate normally (for example, frames
1496 * used as reference pictures).
1497 */
1498 int extra_hw_frames;
1499
1500 /**
1501 * error
1502 * - encoding: Set by libavcodec if flags & AV_CODEC_FLAG_PSNR.
1503 * - decoding: unused
1504 */
1505 uint64_t error[AV_NUM_DATA_POINTERS];
1506
1507 /**
1508 * DCT algorithm, see FF_DCT_* below
1509 * - encoding: Set by user.
1510 * - decoding: unused
1511 */
1512 int dct_algo;
1513#define FF_DCT_AUTO 0
1514#define FF_DCT_FASTINT 1
1515#define FF_DCT_INT 2
1516#define FF_DCT_MMX 3
1517#define FF_DCT_ALTIVEC 5
1518#define FF_DCT_FAAN 6
1519#define FF_DCT_NEON 7
1520
1521 /**
1522 * IDCT algorithm, see FF_IDCT_* below.
1523 * - encoding: Set by user.
1524 * - decoding: Set by user.
1525 */
1526 int idct_algo;
1527#define FF_IDCT_AUTO 0
1528#define FF_IDCT_INT 1
1529#define FF_IDCT_SIMPLE 2
1530#define FF_IDCT_SIMPLEMMX 3
1531#define FF_IDCT_ARM 7
1532#define FF_IDCT_ALTIVEC 8
1533#define FF_IDCT_SIMPLEARM 10
1534#define FF_IDCT_XVID 14
1535#define FF_IDCT_SIMPLEARMV5TE 16
1536#define FF_IDCT_SIMPLEARMV6 17
1537#define FF_IDCT_FAAN 20
1538#define FF_IDCT_SIMPLENEON 22
1539#define FF_IDCT_SIMPLEAUTO 128
1540
1541 /**
1542 * bits per sample/pixel from the demuxer (needed for huffyuv).
1543 * - encoding: Set by libavcodec.
1544 * - decoding: Set by user.
1545 */
1546 int bits_per_coded_sample;
1547
1548 /**
1549 * Bits per sample/pixel of internal libavcodec pixel/sample format.
1550 * - encoding: set by user.
1551 * - decoding: set by libavcodec.
1552 */
1553 int bits_per_raw_sample;
1554
1555 /**
1556 * thread count
1557 * is used to decide how many independent tasks should be passed to execute()
1558 * - encoding: Set by user.
1559 * - decoding: Set by user.
1560 */
1561 int thread_count;
1562
1563 /**
1564 * Which multithreading methods to use.
1565 * Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread,
1566 * so clients which cannot provide future frames should not use it.
1567 *
1568 * - encoding: Set by user, otherwise the default is used.
1569 * - decoding: Set by user, otherwise the default is used.
1570 */
1571 int thread_type;
1572#define FF_THREAD_FRAME 1 ///< Decode more than one frame at once
1573#define FF_THREAD_SLICE 2 ///< Decode more than one part of a single frame at once
1574
1575 /**
1576 * Which multithreading methods are in use by the codec.
1577 * - encoding: Set by libavcodec.
1578 * - decoding: Set by libavcodec.
1579 */
1580 int active_thread_type;
1581
1582 /**
1583 * The codec may call this to execute several independent things.
1584 * It will return only after finishing all tasks.
1585 * The user may replace this with some multithreaded implementation,
1586 * the default implementation will execute the parts serially.
1587 * @param count the number of things to execute
1588 * - encoding: Set by libavcodec, user can override.
1589 * - decoding: Set by libavcodec, user can override.
1590 */
1591 int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);
1592
1593 /**
1594 * The codec may call this to execute several independent things.
1595 * It will return only after finishing all tasks.
1596 * The user may replace this with some multithreaded implementation,
1597 * the default implementation will execute the parts serially.
1598 * @param c context passed also to func
1599 * @param count the number of things to execute
1600 * @param arg2 argument passed unchanged to func
1601 * @param ret return values of executed functions, must have space for "count" values. May be NULL.
1602 * @param func function that will be called count times, with jobnr from 0 to count-1.
1603 * threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
1604 * two instances of func executing at the same time will have the same threadnr.
1605 * @return always 0 currently, but code should handle a future improvement where when any call to func
1606 * returns < 0 no further calls to func may be done and < 0 is returned.
1607 * - encoding: Set by libavcodec, user can override.
1608 * - decoding: Set by libavcodec, user can override.
1609 */
1610 int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);
1611
1612 /**
1613 * profile
1614 * - encoding: Set by user.
1615 * - decoding: Set by libavcodec.
1616 * See the AV_PROFILE_* defines in defs.h.
1617 */
1618 int profile;
1619
1620 /**
1621 * Encoding level descriptor.
1622 * - encoding: Set by user, corresponds to a specific level defined by the
1623 * codec, usually corresponding to the profile level, if not specified it
1624 * is set to AV_LEVEL_UNKNOWN.
1625 * - decoding: Set by libavcodec.
1626 * See AV_LEVEL_* in defs.h.
1627 */
1628 int level;
1629
1630#if FF_API_CODEC_PROPS
1631 /**
1632 * Properties of the stream that gets decoded
1633 * - encoding: unused
1634 * - decoding: set by libavcodec
1635 */
1636 attribute_deprecated
1637 unsigned properties;
1638#define FF_CODEC_PROPERTY_LOSSLESS 0x00000001
1639#define FF_CODEC_PROPERTY_CLOSED_CAPTIONS 0x00000002
1640#define FF_CODEC_PROPERTY_FILM_GRAIN 0x00000004
1641#endif
1642
1643 /**
1644 * Skip loop filtering for selected frames.
1645 * - encoding: unused
1646 * - decoding: Set by user.
1647 */
1648 enum AVDiscard skip_loop_filter;
1649
1650 /**
1651 * Skip IDCT/dequantization for selected frames.
1652 * - encoding: unused
1653 * - decoding: Set by user.
1654 */
1655 enum AVDiscard skip_idct;
1656
1657 /**
1658 * Skip decoding for selected frames.
1659 * - encoding: unused
1660 * - decoding: Set by user.
1661 */
1662 enum AVDiscard skip_frame;
1663
1664 /**
1665 * Skip processing alpha if supported by codec.
1666 * Note that if the format uses pre-multiplied alpha (common with VP6,
1667 * and recommended due to better video quality/compression)
1668 * the image will look as if alpha-blended onto a black background.
1669 * However for formats that do not use pre-multiplied alpha
1670 * there might be serious artefacts (though e.g. libswscale currently
1671 * assumes pre-multiplied alpha anyway).
1672 *
1673 * - decoding: set by user
1674 * - encoding: unused
1675 */
1676 int skip_alpha;
1677
1678 /**
1679 * Number of macroblock rows at the top which are skipped.
1680 * - encoding: unused
1681 * - decoding: Set by user.
1682 */
1683 int skip_top;
1684
1685 /**
1686 * Number of macroblock rows at the bottom which are skipped.
1687 * - encoding: unused
1688 * - decoding: Set by user.
1689 */
1690 int skip_bottom;
1691
1692 /**
1693 * low resolution decoding, 1-> 1/2 size, 2->1/4 size
1694 * - encoding: unused
1695 * - decoding: Set by user.
1696 */
1697 int lowres;
1698
1699 /**
1700 * AVCodecDescriptor
1701 * - encoding: unused.
1702 * - decoding: set by libavcodec.
1703 */
1704 const struct AVCodecDescriptor *codec_descriptor;
1705
1706 /**
1707 * Character encoding of the input subtitles file.
1708 * - decoding: set by user
1709 * - encoding: unused
1710 */
1711 char *sub_charenc;
1712
1713 /**
1714 * Subtitles character encoding mode. Formats or codecs might be adjusting
1715 * this setting (if they are doing the conversion themselves for instance).
1716 * - decoding: set by libavcodec
1717 * - encoding: unused
1718 */
1719 int sub_charenc_mode;
1720#define FF_SUB_CHARENC_MODE_DO_NOTHING -1 ///< do nothing (demuxer outputs a stream supposed to be already in UTF-8, or the codec is bitmap for instance)
1721#define FF_SUB_CHARENC_MODE_AUTOMATIC 0 ///< libavcodec will select the mode itself
1722#define FF_SUB_CHARENC_MODE_PRE_DECODER 1 ///< the AVPacket data needs to be recoded to UTF-8 before being fed to the decoder, requires iconv
1723#define FF_SUB_CHARENC_MODE_IGNORE 2 ///< neither convert the subtitles, nor check them for valid UTF-8
1724
1725 /**
1726 * Header containing style information for text subtitles.
1727 * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
1728 * [Script Info] and [V4+ Styles] section, plus the [Events] line and
1729 * the Format line following. It shouldn't include any Dialogue line.
1730 *
1731 * - encoding: May be set by the caller before avcodec_open2() to an array
1732 * allocated with the av_malloc() family of functions.
1733 * - decoding: May be set by libavcodec in avcodec_open2().
1734 *
1735 * After being set, the array is owned by the codec and freed in
1736 * avcodec_free_context().
1737 */
1738 int subtitle_header_size;
1739 uint8_t *subtitle_header;
1740
1741 /**
1742 * dump format separator.
1743 * can be ", " or "\n " or anything else
1744 * - encoding: Set by user.
1745 * - decoding: Set by user.
1746 */
1747 uint8_t *dump_separator;
1748
1749 /**
1750 * ',' separated list of allowed decoders.
1751 * If NULL then all are allowed
1752 * - encoding: unused
1753 * - decoding: set by user
1754 */
1755 char *codec_whitelist;
1756
1757 /**
1758 * Additional data associated with the entire coded stream.
1759 *
1760 * - decoding: may be set by user before calling avcodec_open2().
1761 * - encoding: may be set by libavcodec after avcodec_open2().
1762 */
1763 AVPacketSideData *coded_side_data;
1764 int nb_coded_side_data;
1765
1766 /**
1767 * Bit set of AV_CODEC_EXPORT_DATA_* flags, which affects the kind of
1768 * metadata exported in frame, packet, or coded stream side data by
1769 * decoders and encoders.
1770 *
1771 * - decoding: set by user
1772 * - encoding: set by user
1773 */
1774 int export_side_data;
1775
1776 /**
1777 * The number of pixels per image to maximally accept.
1778 *
1779 * - decoding: set by user
1780 * - encoding: set by user
1781 */
1782 int64_t max_pixels;
1783
1784 /**
1785 * Video decoding only. Certain video codecs support cropping, meaning that
1786 * only a sub-rectangle of the decoded frame is intended for display. This
1787 * option controls how cropping is handled by libavcodec.
1788 *
1789 * When set to 1 (the default), libavcodec will apply cropping internally.
1790 * I.e. it will modify the output frame width/height fields and offset the
1791 * data pointers (only by as much as possible while preserving alignment, or
1792 * by the full amount if the AV_CODEC_FLAG_UNALIGNED flag is set) so that
1793 * the frames output by the decoder refer only to the cropped area. The
1794 * crop_* fields of the output frames will be zero.
1795 *
1796 * When set to 0, the width/height fields of the output frames will be set
1797 * to the coded dimensions and the crop_* fields will describe the cropping
1798 * rectangle. Applying the cropping is left to the caller.
1799 *
1800 * @warning When hardware acceleration with opaque output frames is used,
1801 * libavcodec is unable to apply cropping from the top/left border.
1802 *
1803 * @note when this option is set to zero, the width/height fields of the
1804 * AVCodecContext and output AVFrames have different meanings. The codec
1805 * context fields store display dimensions (with the coded dimensions in
1806 * coded_width/height), while the frame fields store the coded dimensions
1807 * (with the display dimensions being determined by the crop_* fields).
1808 */
1809 int apply_cropping;
1810
1811 /**
1812 * The percentage of damaged samples to discard a frame.
1813 *
1814 * - decoding: set by user
1815 * - encoding: unused
1816 */
1817 int discard_damaged_percentage;
1818
1819 /**
1820 * The number of samples per frame to maximally accept.
1821 *
1822 * - decoding: set by user
1823 * - encoding: set by user
1824 */
1825 int64_t max_samples;
1826
1827 /**
1828 * This callback is called at the beginning of each packet to get a data
1829 * buffer for it.
1830 *
1831 * The following field will be set in the packet before this callback is
1832 * called:
1833 * - size
1834 * This callback must use the above value to calculate the required buffer size,
1835 * which must padded by at least AV_INPUT_BUFFER_PADDING_SIZE bytes.
1836 *
1837 * In some specific cases, the encoder may not use the entire buffer allocated by this
1838 * callback. This will be reflected in the size value in the packet once returned by
1839 * avcodec_receive_packet().
1840 *
1841 * This callback must fill the following fields in the packet:
1842 * - data: alignment requirements for AVPacket apply, if any. Some architectures and
1843 * encoders may benefit from having aligned data.
1844 * - buf: must contain a pointer to an AVBufferRef structure. The packet's
1845 * data pointer must be contained in it. See: av_buffer_create(), av_buffer_alloc(),
1846 * and av_buffer_ref().
1847 *
1848 * If AV_CODEC_CAP_DR1 is not set then get_encode_buffer() must call
1849 * avcodec_default_get_encode_buffer() instead of providing a buffer allocated by
1850 * some other means.
1851 *
1852 * The flags field may contain a combination of AV_GET_ENCODE_BUFFER_FLAG_ flags.
1853 * They may be used for example to hint what use the buffer may get after being
1854 * created.
1855 * Implementations of this callback may ignore flags they don't understand.
1856 * If AV_GET_ENCODE_BUFFER_FLAG_REF is set in flags then the packet may be reused
1857 * (read and/or written to if it is writable) later by libavcodec.
1858 *
1859 * This callback must be thread-safe, as when frame threading is used, it may
1860 * be called from multiple threads simultaneously.
1861 *
1862 * @see avcodec_default_get_encode_buffer()
1863 *
1864 * - encoding: Set by libavcodec, user can override.
1865 * - decoding: unused
1866 */
1867 int (*get_encode_buffer)(struct AVCodecContext *s, AVPacket *pkt, int flags);
1868
1869 /**
1870 * Frame counter, set by libavcodec.
1871 *
1872 * - decoding: total number of frames returned from the decoder so far.
1873 * - encoding: total number of frames passed to the encoder so far.
1874 *
1875 * @note the counter is not incremented if encoding/decoding resulted in
1876 * an error.
1877 */
1878 int64_t frame_num;
1879
1880 /**
1881 * Decoding only. May be set by the caller before avcodec_open2() to an
1882 * av_malloc()'ed array (or via AVOptions). Owned and freed by the decoder
1883 * afterwards.
1884 *
1885 * Side data attached to decoded frames may come from several sources:
1886 * 1. coded_side_data, which the decoder will for certain types translate
1887 * from packet-type to frame-type and attach to frames;
1888 * 2. side data attached to an AVPacket sent for decoding (same
1889 * considerations as above);
1890 * 3. extracted from the coded bytestream.
1891 * The first two cases are supplied by the caller and typically come from a
1892 * container.
1893 *
1894 * This array configures decoder behaviour in cases when side data of the
1895 * same type is present both in the coded bytestream and in the
1896 * user-supplied side data (items 1. and 2. above). In all cases, at most
1897 * one instance of each side data type will be attached to output frames. By
1898 * default it will be the bytestream side data. Adding an
1899 * AVPacketSideDataType value to this array will flip the preference for
1900 * this type, thus making the decoder prefer user-supplied side data over
1901 * bytestream. In case side data of the same type is present both in
1902 * coded_data and attacked to a packet, the packet instance always has
1903 * priority.
1904 *
1905 * The array may also contain a single -1, in which case the preference is
1906 * switched for all side data types.
1907 */
1908 int *side_data_prefer_packet;
1909 /**
1910 * Number of entries in side_data_prefer_packet.
1911 */
1912 unsigned nb_side_data_prefer_packet;
1913
1914 /**
1915 * Array containing static side data, such as HDR10 CLL / MDCV structures.
1916 * Side data entries should be allocated by usage of helpers defined in
1917 * libavutil/frame.h.
1918 *
1919 * - encoding: may be set by user before calling avcodec_open2() for
1920 * encoder configuration. Afterwards owned and freed by the
1921 * encoder.
1922 * - decoding: may be set by libavcodec in avcodec_open2().
1923 */
1924 AVFrameSideData **decoded_side_data;
1925 int nb_decoded_side_data;
1926} AVCodecContext;
1927
1928/**
1929 * @defgroup lavc_hwaccel AVHWAccel
1930 *
1931 * @note Nothing in this structure should be accessed by the user. At some
1932 * point in future it will not be externally visible at all.
1933 *
1934 * @{
1935 */
1936typedef struct AVHWAccel {
1937 /**
1938 * Name of the hardware accelerated codec.
1939 * The name is globally unique among encoders and among decoders (but an
1940 * encoder and a decoder can share the same name).
1941 */
1942 const char *name;
1943
1944 /**
1945 * Type of codec implemented by the hardware accelerator.
1946 *
1947 * See AVMEDIA_TYPE_xxx
1948 */
1949 enum AVMediaType type;
1950
1951 /**
1952 * Codec implemented by the hardware accelerator.
1953 *
1954 * See AV_CODEC_ID_xxx
1955 */
1956 enum AVCodecID id;
1957
1958 /**
1959 * Supported pixel format.
1960 *
1961 * Only hardware accelerated formats are supported here.
1962 */
1963 enum AVPixelFormat pix_fmt;
1964
1965 /**
1966 * Hardware accelerated codec capabilities.
1967 * see AV_HWACCEL_CODEC_CAP_*
1968 */
1969 int capabilities;
1970} AVHWAccel;
1971
1972/**
1973 * HWAccel is experimental and is thus avoided in favor of non experimental
1974 * codecs
1975 */
1976#define AV_HWACCEL_CODEC_CAP_EXPERIMENTAL 0x0200
1977
1978/**
1979 * Hardware acceleration should be used for decoding even if the codec level
1980 * used is unknown or higher than the maximum supported level reported by the
1981 * hardware driver.
1982 *
1983 * It's generally a good idea to pass this flag unless you have a specific
1984 * reason not to, as hardware tends to under-report supported levels.
1985 */
1986#define AV_HWACCEL_FLAG_IGNORE_LEVEL (1 << 0)
1987
1988/**
1989 * Hardware acceleration can output YUV pixel formats with a different chroma
1990 * sampling than 4:2:0 and/or other than 8 bits per component.
1991 */
1992#define AV_HWACCEL_FLAG_ALLOW_HIGH_DEPTH (1 << 1)
1993
1994/**
1995 * Hardware acceleration should still be attempted for decoding when the
1996 * codec profile does not match the reported capabilities of the hardware.
1997 *
1998 * For example, this can be used to try to decode baseline profile H.264
1999 * streams in hardware - it will often succeed, because many streams marked
2000 * as baseline profile actually conform to constrained baseline profile.
2001 *
2002 * @warning If the stream is actually not supported then the behaviour is
2003 * undefined, and may include returning entirely incorrect output
2004 * while indicating success.
2005 */
2006#define AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH (1 << 2)
2007
2008/**
2009 * Some hardware decoders (namely nvdec) can either output direct decoder
2010 * surfaces, or make an on-device copy and return said copy.
2011 * There is a hard limit on how many decoder surfaces there can be, and it
2012 * cannot be accurately guessed ahead of time.
2013 * For some processing chains, this can be okay, but others will run into the
2014 * limit and in turn produce very confusing errors that require fine tuning of
2015 * more or less obscure options by the user, or in extreme cases cannot be
2016 * resolved at all without inserting an avfilter that forces a copy.
2017 *
2018 * Thus, the hwaccel will by default make a copy for safety and resilience.
2019 * If a users really wants to minimize the amount of copies, they can set this
2020 * flag and ensure their processing chain does not exhaust the surface pool.
2021 */
2022#define AV_HWACCEL_FLAG_UNSAFE_OUTPUT (1 << 3)
2023
2024/**
2025 * @}
2026 */
2027
2028enum AVSubtitleType {
2029 SUBTITLE_NONE,
2030
2031 SUBTITLE_BITMAP, ///< A bitmap, pict will be set
2032
2033 /**
2034 * Plain text, the text field must be set by the decoder and is
2035 * authoritative. ass and pict fields may contain approximations.
2036 */
2037 SUBTITLE_TEXT,
2038
2039 /**
2040 * Formatted text, the ass field must be set by the decoder and is
2041 * authoritative. pict and text fields may contain approximations.
2042 */
2043 SUBTITLE_ASS,
2044};
2045
2046#define AV_SUBTITLE_FLAG_FORCED 0x00000001
2047
2048typedef struct AVSubtitleRect {
2049 int x; ///< top left corner of pict, undefined when pict is not set
2050 int y; ///< top left corner of pict, undefined when pict is not set
2051 int w; ///< width of pict, undefined when pict is not set
2052 int h; ///< height of pict, undefined when pict is not set
2053 int nb_colors; ///< number of colors in pict, undefined when pict is not set
2054
2055 /**
2056 * data+linesize for the bitmap of this subtitle.
2057 * Can be set for text/ass as well once they are rendered.
2058 */
2059 uint8_t *data[4];
2060 int linesize[4];
2061
2062 int flags;
2063 enum AVSubtitleType type;
2064
2065 char *text; ///< 0 terminated plain UTF-8 text
2066
2067 /**
2068 * 0 terminated ASS/SSA compatible event line.
2069 * The presentation of this is unaffected by the other values in this
2070 * struct.
2071 */
2072 char *ass;
2073} AVSubtitleRect;
2074
2075typedef struct AVSubtitle {
2076 uint16_t format; /* 0 = graphics */
2077 uint32_t start_display_time; /* relative to packet pts, in ms */
2078 uint32_t end_display_time; /* relative to packet pts, in ms */
2079 unsigned num_rects;
2080 AVSubtitleRect **rects;
2081 int64_t pts; ///< Same as packet pts, in AV_TIME_BASE
2082} AVSubtitle;
2083
2084/**
2085 * Return the LIBAVCODEC_VERSION_INT constant.
2086 */
2087unsigned avcodec_version(void);
2088
2089/**
2090 * Return the libavcodec build-time configuration.
2091 */
2092const char *avcodec_configuration(void);
2093
2094/**
2095 * Return the libavcodec license.
2096 */
2097const char *avcodec_license(void);
2098
2099/**
2100 * Allocate an AVCodecContext and set its fields to default values. The
2101 * resulting struct should be freed with avcodec_free_context().
2102 *
2103 * @param codec if non-NULL, allocate private data and initialize defaults
2104 * for the given codec. It is illegal to then call avcodec_open2()
2105 * with a different codec.
2106 * If NULL, then the codec-specific defaults won't be initialized,
2107 * which may result in suboptimal default settings (this is
2108 * important mainly for encoders, e.g. libx264).
2109 *
2110 * @return An AVCodecContext filled with default values or NULL on failure.
2111 */
2112AVCodecContext *avcodec_alloc_context3(const AVCodec *codec);
2113
2114/**
2115 * Free the codec context and everything associated with it and write NULL to
2116 * the provided pointer.
2117 */
2118void avcodec_free_context(AVCodecContext **avctx);
2119
2120/**
2121 * Get the AVClass for AVCodecContext. It can be used in combination with
2122 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
2123 *
2124 * @see av_opt_find().
2125 */
2126const AVClass *avcodec_get_class(void);
2127
2128/**
2129 * Get the AVClass for AVSubtitleRect. It can be used in combination with
2130 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
2131 *
2132 * @see av_opt_find().
2133 */
2134const AVClass *avcodec_get_subtitle_rect_class(void);
2135
2136/**
2137 * Fill the parameters struct based on the values from the supplied codec
2138 * context. Any allocated fields in par are freed and replaced with duplicates
2139 * of the corresponding fields in codec.
2140 *
2141 * @return >= 0 on success, a negative AVERROR code on failure
2142 */
2143int avcodec_parameters_from_context(struct AVCodecParameters *par,
2144 const AVCodecContext *codec);
2145
2146/**
2147 * Fill the codec context based on the values from the supplied codec
2148 * parameters. Any allocated fields in codec that have a corresponding field in
2149 * par are freed and replaced with duplicates of the corresponding field in par.
2150 * Fields in codec that do not have a counterpart in par are not touched.
2151 *
2152 * @return >= 0 on success, a negative AVERROR code on failure.
2153 */
2154int avcodec_parameters_to_context(AVCodecContext *codec,
2155 const struct AVCodecParameters *par);
2156
2157/**
2158 * Initialize the AVCodecContext to use the given AVCodec. Prior to using this
2159 * function the context has to be allocated with avcodec_alloc_context3().
2160 *
2161 * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
2162 * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
2163 * retrieving a codec.
2164 *
2165 * Depending on the codec, you might need to set options in the codec context
2166 * also for decoding (e.g. width, height, or the pixel or audio sample format in
2167 * the case the information is not available in the bitstream, as when decoding
2168 * raw audio or video).
2169 *
2170 * Options in the codec context can be set either by setting them in the options
2171 * AVDictionary, or by setting the values in the context itself, directly or by
2172 * using the av_opt_set() API before calling this function.
2173 *
2174 * Example:
2175 * @code
2176 * av_dict_set(&opts, "b", "2.5M", 0);
2177 * codec = avcodec_find_decoder(AV_CODEC_ID_H264);
2178 * if (!codec)
2179 * exit(1);
2180 *
2181 * context = avcodec_alloc_context3(codec);
2182 *
2183 * if (avcodec_open2(context, codec, opts) < 0)
2184 * exit(1);
2185 * @endcode
2186 *
2187 * In the case AVCodecParameters are available (e.g. when demuxing a stream
2188 * using libavformat, and accessing the AVStream contained in the demuxer), the
2189 * codec parameters can be copied to the codec context using
2190 * avcodec_parameters_to_context(), as in the following example:
2191 *
2192 * @code
2193 * AVStream *stream = ...;
2194 * context = avcodec_alloc_context3(codec);
2195 * if (avcodec_parameters_to_context(context, stream->codecpar) < 0)
2196 * exit(1);
2197 * if (avcodec_open2(context, codec, NULL) < 0)
2198 * exit(1);
2199 * @endcode
2200 *
2201 * @note Always call this function before using decoding routines (such as
2202 * @ref avcodec_receive_frame()).
2203 *
2204 * @param avctx The context to initialize.
2205 * @param codec The codec to open this context for. If a non-NULL codec has been
2206 * previously passed to avcodec_alloc_context3() or
2207 * for this context, then this parameter MUST be either NULL or
2208 * equal to the previously passed codec.
2209 * @param options A dictionary filled with AVCodecContext and codec-private
2210 * options, which are set on top of the options already set in
2211 * avctx, can be NULL. On return this object will be filled with
2212 * options that were not found in the avctx codec context.
2213 *
2214 * @return zero on success, a negative value on error
2215 * @see avcodec_alloc_context3(), avcodec_find_decoder(), avcodec_find_encoder(),
2216 * av_dict_set(), av_opt_set(), av_opt_find(), avcodec_parameters_to_context()
2217 */
2218int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
2219
2220/**
2221 * Free all allocated data in the given subtitle struct.
2222 *
2223 * @param sub AVSubtitle to free.
2224 */
2225void avsubtitle_free(AVSubtitle *sub);
2226
2227/**
2228 * @}
2229 */
2230
2231/**
2232 * @addtogroup lavc_decoding
2233 * @{
2234 */
2235
2236/**
2237 * The default callback for AVCodecContext.get_buffer2(). It is made public so
2238 * it can be called by custom get_buffer2() implementations for decoders without
2239 * AV_CODEC_CAP_DR1 set.
2240 */
2241int avcodec_default_get_buffer2(AVCodecContext *s, AVFrame *frame, int flags);
2242
2243/**
2244 * The default callback for AVCodecContext.get_encode_buffer(). It is made public so
2245 * it can be called by custom get_encode_buffer() implementations for encoders without
2246 * AV_CODEC_CAP_DR1 set.
2247 */
2248int avcodec_default_get_encode_buffer(AVCodecContext *s, AVPacket *pkt, int flags);
2249
2250/**
2251 * Modify width and height values so that they will result in a memory
2252 * buffer that is acceptable for the codec if you do not use any horizontal
2253 * padding.
2254 *
2255 * May only be used if a codec with AV_CODEC_CAP_DR1 has been opened.
2256 */
2257void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);
2258
2259/**
2260 * Modify width and height values so that they will result in a memory
2261 * buffer that is acceptable for the codec if you also ensure that all
2262 * line sizes are a multiple of the respective linesize_align[i].
2263 *
2264 * May only be used if a codec with AV_CODEC_CAP_DR1 has been opened.
2265 */
2266void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
2267 int linesize_align[AV_NUM_DATA_POINTERS]);
2268
2269/**
2270 * Decode a subtitle message.
2271 * Return a negative value on error, otherwise return the number of bytes used.
2272 * If no subtitle could be decompressed, got_sub_ptr is zero.
2273 * Otherwise, the subtitle is stored in *sub.
2274 * Note that AV_CODEC_CAP_DR1 is not available for subtitle codecs. This is for
2275 * simplicity, because the performance difference is expected to be negligible
2276 * and reusing a get_buffer written for video codecs would probably perform badly
2277 * due to a potentially very different allocation pattern.
2278 *
2279 * Some decoders (those marked with AV_CODEC_CAP_DELAY) have a delay between input
2280 * and output. This means that for some packets they will not immediately
2281 * produce decoded output and need to be flushed at the end of decoding to get
2282 * all the decoded data. Flushing is done by calling this function with packets
2283 * with avpkt->data set to NULL and avpkt->size set to 0 until it stops
2284 * returning subtitles. It is safe to flush even those decoders that are not
2285 * marked with AV_CODEC_CAP_DELAY, then no subtitles will be returned.
2286 *
2287 * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
2288 * before packets may be fed to the decoder.
2289 *
2290 * @param avctx the codec context
2291 * @param[out] sub The preallocated AVSubtitle in which the decoded subtitle will be stored,
2292 * must be freed with avsubtitle_free if *got_sub_ptr is set.
2293 * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
2294 * @param[in] avpkt The input AVPacket containing the input buffer.
2295 */
2296int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
2297 int *got_sub_ptr, const AVPacket *avpkt);
2298
2299/**
2300 * Supply raw packet data as input to a decoder.
2301 *
2302 * Internally, this call will copy relevant AVCodecContext fields, which can
2303 * influence decoding per-packet, and apply them when the packet is actually
2304 * decoded. (For example AVCodecContext.skip_frame, which might direct the
2305 * decoder to drop the frame contained by the packet sent with this function.)
2306 *
2307 * @warning The input buffer, avpkt->data must be AV_INPUT_BUFFER_PADDING_SIZE
2308 * larger than the actual read bytes because some optimized bitstream
2309 * readers read 32 or 64 bits at once and could read over the end.
2310 *
2311 * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
2312 * before packets may be fed to the decoder.
2313 *
2314 * @param avctx codec context
2315 * @param[in] avpkt The input AVPacket. Usually, this will be a single video
2316 * frame, or several complete audio frames.
2317 * Ownership of the packet remains with the caller, and the
2318 * decoder will not write to the packet. The decoder may create
2319 * a reference to the packet data (or copy it if the packet is
2320 * not reference-counted).
2321 * Unlike with older APIs, the packet is always fully consumed,
2322 * and if it contains multiple frames (e.g. some audio codecs),
2323 * will require you to call avcodec_receive_frame() multiple
2324 * times afterwards before you can send a new packet.
2325 * It can be NULL (or an AVPacket with data set to NULL and
2326 * size set to 0); in this case, it is considered a flush
2327 * packet, which signals the end of the stream. Sending the
2328 * first flush packet will return success. Subsequent ones are
2329 * unnecessary and will return AVERROR_EOF. If the decoder
2330 * still has frames buffered, it will return them after sending
2331 * a flush packet.
2332 *
2333 * @retval 0 success
2334 * @retval AVERROR(EAGAIN) input is not accepted in the current state - user
2335 * must read output with avcodec_receive_frame() (once
2336 * all output is read, the packet should be resent,
2337 * and the call will not fail with EAGAIN).
2338 * @retval AVERROR_EOF the decoder has been flushed, and no new packets can be
2339 * sent to it (also returned if more than 1 flush
2340 * packet is sent)
2341 * @retval AVERROR(EINVAL) codec not opened, it is an encoder, or requires flush
2342 * @retval AVERROR(ENOMEM) failed to add packet to internal queue, or similar
2343 * @retval "another negative error code" legitimate decoding errors
2344 */
2345int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);
2346
2347/**
2348 * Return decoded output data from a decoder or encoder (when the
2349 * @ref AV_CODEC_FLAG_RECON_FRAME flag is used).
2350 *
2351 * @param avctx codec context
2352 * @param frame This will be set to a reference-counted video or audio
2353 * frame (depending on the decoder type) allocated by the
2354 * codec. Note that the function will always call
2355 * av_frame_unref(frame) before doing anything else.
2356 *
2357 * @retval 0 success, a frame was returned
2358 * @retval AVERROR(EAGAIN) output is not available in this state - user must
2359 * try to send new input
2360 * @retval AVERROR_EOF the codec has been fully flushed, and there will be
2361 * no more output frames
2362 * @retval AVERROR(EINVAL) codec not opened, or it is an encoder without the
2363 * @ref AV_CODEC_FLAG_RECON_FRAME flag enabled
2364 * @retval "other negative error code" legitimate decoding errors
2365 */
2366int avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame);
2367
2368/**
2369 * Supply a raw video or audio frame to the encoder. Use avcodec_receive_packet()
2370 * to retrieve buffered output packets.
2371 *
2372 * @param avctx codec context
2373 * @param[in] frame AVFrame containing the raw audio or video frame to be encoded.
2374 * Ownership of the frame remains with the caller, and the
2375 * encoder will not write to the frame. The encoder may create
2376 * a reference to the frame data (or copy it if the frame is
2377 * not reference-counted).
2378 * It can be NULL, in which case it is considered a flush
2379 * packet. This signals the end of the stream. If the encoder
2380 * still has packets buffered, it will return them after this
2381 * call. Once flushing mode has been entered, additional flush
2382 * packets are ignored, and sending frames will return
2383 * AVERROR_EOF.
2384 *
2385 * For audio:
2386 * If AV_CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
2387 * can have any number of samples.
2388 * If it is not set, frame->nb_samples must be equal to
2389 * avctx->frame_size for all frames except the last.
2390 * The final frame may be smaller than avctx->frame_size.
2391 * @retval 0 success
2392 * @retval AVERROR(EAGAIN) input is not accepted in the current state - user must
2393 * read output with avcodec_receive_packet() (once all
2394 * output is read, the packet should be resent, and the
2395 * call will not fail with EAGAIN).
2396 * @retval AVERROR_EOF the encoder has been flushed, and no new frames can
2397 * be sent to it
2398 * @retval AVERROR(EINVAL) codec not opened, it is a decoder, or requires flush
2399 * @retval AVERROR(ENOMEM) failed to add packet to internal queue, or similar
2400 * @retval "another negative error code" legitimate encoding errors
2401 */
2402int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame);
2403
2404/**
2405 * Read encoded data from the encoder.
2406 *
2407 * @param avctx codec context
2408 * @param avpkt This will be set to a reference-counted packet allocated by the
2409 * encoder. Note that the function will always call
2410 * av_packet_unref(avpkt) before doing anything else.
2411 * @retval 0 success
2412 * @retval AVERROR(EAGAIN) output is not available in the current state - user must
2413 * try to send input
2414 * @retval AVERROR_EOF the encoder has been fully flushed, and there will be no
2415 * more output packets
2416 * @retval AVERROR(EINVAL) codec not opened, or it is a decoder
2417 * @retval "another negative error code" legitimate encoding errors
2418 */
2419int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt);
2420
2421/**
2422 * Create and return a AVHWFramesContext with values adequate for hardware
2423 * decoding. This is meant to get called from the get_format callback, and is
2424 * a helper for preparing a AVHWFramesContext for AVCodecContext.hw_frames_ctx.
2425 * This API is for decoding with certain hardware acceleration modes/APIs only.
2426 *
2427 * The returned AVHWFramesContext is not initialized. The caller must do this
2428 * with av_hwframe_ctx_init().
2429 *
2430 * Calling this function is not a requirement, but makes it simpler to avoid
2431 * codec or hardware API specific details when manually allocating frames.
2432 *
2433 * Alternatively to this, an API user can set AVCodecContext.hw_device_ctx,
2434 * which sets up AVCodecContext.hw_frames_ctx fully automatically, and makes
2435 * it unnecessary to call this function or having to care about
2436 * AVHWFramesContext initialization at all.
2437 *
2438 * There are a number of requirements for calling this function:
2439 *
2440 * - It must be called from get_format with the same avctx parameter that was
2441 * passed to get_format. Calling it outside of get_format is not allowed, and
2442 * can trigger undefined behavior.
2443 * - The function is not always supported (see description of return values).
2444 * Even if this function returns successfully, hwaccel initialization could
2445 * fail later. (The degree to which implementations check whether the stream
2446 * is actually supported varies. Some do this check only after the user's
2447 * get_format callback returns.)
2448 * - The hw_pix_fmt must be one of the choices suggested by get_format. If the
2449 * user decides to use a AVHWFramesContext prepared with this API function,
2450 * the user must return the same hw_pix_fmt from get_format.
2451 * - The device_ref passed to this function must support the given hw_pix_fmt.
2452 * - After calling this API function, it is the user's responsibility to
2453 * initialize the AVHWFramesContext (returned by the out_frames_ref parameter),
2454 * and to set AVCodecContext.hw_frames_ctx to it. If done, this must be done
2455 * before returning from get_format (this is implied by the normal
2456 * AVCodecContext.hw_frames_ctx API rules).
2457 * - The AVHWFramesContext parameters may change every time time get_format is
2458 * called. Also, AVCodecContext.hw_frames_ctx is reset before get_format. So
2459 * you are inherently required to go through this process again on every
2460 * get_format call.
2461 * - It is perfectly possible to call this function without actually using
2462 * the resulting AVHWFramesContext. One use-case might be trying to reuse a
2463 * previously initialized AVHWFramesContext, and calling this API function
2464 * only to test whether the required frame parameters have changed.
2465 * - Fields that use dynamically allocated values of any kind must not be set
2466 * by the user unless setting them is explicitly allowed by the documentation.
2467 * If the user sets AVHWFramesContext.free and AVHWFramesContext.user_opaque,
2468 * the new free callback must call the potentially set previous free callback.
2469 * This API call may set any dynamically allocated fields, including the free
2470 * callback.
2471 *
2472 * The function will set at least the following fields on AVHWFramesContext
2473 * (potentially more, depending on hwaccel API):
2474 *
2475 * - All fields set by av_hwframe_ctx_alloc().
2476 * - Set the format field to hw_pix_fmt.
2477 * - Set the sw_format field to the most suited and most versatile format. (An
2478 * implication is that this will prefer generic formats over opaque formats
2479 * with arbitrary restrictions, if possible.)
2480 * - Set the width/height fields to the coded frame size, rounded up to the
2481 * API-specific minimum alignment.
2482 * - Only _if_ the hwaccel requires a pre-allocated pool: set the initial_pool_size
2483 * field to the number of maximum reference surfaces possible with the codec,
2484 * plus 1 surface for the user to work (meaning the user can safely reference
2485 * at most 1 decoded surface at a time), plus additional buffering introduced
2486 * by frame threading. If the hwaccel does not require pre-allocation, the
2487 * field is left to 0, and the decoder will allocate new surfaces on demand
2488 * during decoding.
2489 * - Possibly AVHWFramesContext.hwctx fields, depending on the underlying
2490 * hardware API.
2491 *
2492 * Essentially, out_frames_ref returns the same as av_hwframe_ctx_alloc(), but
2493 * with basic frame parameters set.
2494 *
2495 * The function is stateless, and does not change the AVCodecContext or the
2496 * device_ref AVHWDeviceContext.
2497 *
2498 * @param avctx The context which is currently calling get_format, and which
2499 * implicitly contains all state needed for filling the returned
2500 * AVHWFramesContext properly.
2501 * @param device_ref A reference to the AVHWDeviceContext describing the device
2502 * which will be used by the hardware decoder.
2503 * @param hw_pix_fmt The hwaccel format you are going to return from get_format.
2504 * @param out_frames_ref On success, set to a reference to an _uninitialized_
2505 * AVHWFramesContext, created from the given device_ref.
2506 * Fields will be set to values required for decoding.
2507 * Not changed if an error is returned.
2508 * @return zero on success, a negative value on error. The following error codes
2509 * have special semantics:
2510 * AVERROR(ENOENT): the decoder does not support this functionality. Setup
2511 * is always manual, or it is a decoder which does not
2512 * support setting AVCodecContext.hw_frames_ctx at all,
2513 * or it is a software format.
2514 * AVERROR(EINVAL): it is known that hardware decoding is not supported for
2515 * this configuration, or the device_ref is not supported
2516 * for the hwaccel referenced by hw_pix_fmt.
2517 */
2518int avcodec_get_hw_frames_parameters(AVCodecContext *avctx,
2519 AVBufferRef *device_ref,
2520 enum AVPixelFormat hw_pix_fmt,
2521 AVBufferRef **out_frames_ref);
2522
2523enum AVCodecConfig {
2524 AV_CODEC_CONFIG_PIX_FORMAT, ///< AVPixelFormat, terminated by AV_PIX_FMT_NONE
2525 AV_CODEC_CONFIG_FRAME_RATE, ///< AVRational, terminated by {0, 0}
2526 AV_CODEC_CONFIG_SAMPLE_RATE, ///< int, terminated by 0
2527 AV_CODEC_CONFIG_SAMPLE_FORMAT, ///< AVSampleFormat, terminated by AV_SAMPLE_FMT_NONE
2528 AV_CODEC_CONFIG_CHANNEL_LAYOUT, ///< AVChannelLayout, terminated by {0}
2529 AV_CODEC_CONFIG_COLOR_RANGE, ///< AVColorRange, terminated by AVCOL_RANGE_UNSPECIFIED
2530 AV_CODEC_CONFIG_COLOR_SPACE, ///< AVColorSpace, terminated by AVCOL_SPC_UNSPECIFIED
2531};
2532
2533/**
2534 * Retrieve a list of all supported values for a given configuration type.
2535 *
2536 * @param avctx An optional context to use. Values such as
2537 * `strict_std_compliance` may affect the result. If NULL,
2538 * default values are used.
2539 * @param codec The codec to query, or NULL to use avctx->codec.
2540 * @param config The configuration to query.
2541 * @param flags Currently unused; should be set to zero.
2542 * @param out_configs On success, set to a list of configurations, terminated
2543 * by a config-specific terminator, or NULL if all
2544 * possible values are supported.
2545 * @param out_num_configs On success, set to the number of elements in
2546 *out_configs, excluding the terminator. Optional.
2547 */
2548int avcodec_get_supported_config(const AVCodecContext *avctx,
2549 const AVCodec *codec, enum AVCodecConfig config,
2550 unsigned flags, const void **out_configs,
2551 int *out_num_configs);
2552
2553
2554
2555/**
2556 * @defgroup lavc_parsing Frame parsing
2557 * @{
2558 */
2559
2560enum AVPictureStructure {
2561 AV_PICTURE_STRUCTURE_UNKNOWN, ///< unknown
2562 AV_PICTURE_STRUCTURE_TOP_FIELD, ///< coded as top field
2563 AV_PICTURE_STRUCTURE_BOTTOM_FIELD, ///< coded as bottom field
2564 AV_PICTURE_STRUCTURE_FRAME, ///< coded as frame
2565};
2566
2567typedef struct AVCodecParserContext {
2568 void *priv_data;
2569 const struct AVCodecParser *parser;
2570 int64_t frame_offset; /* offset of the current frame */
2571 int64_t cur_offset; /* current offset
2572 (incremented by each av_parser_parse()) */
2573 int64_t next_frame_offset; /* offset of the next frame */
2574 /* video info */
2575 int pict_type; /* XXX: Put it back in AVCodecContext. */
2576 /**
2577 * This field is used for proper frame duration computation in lavf.
2578 * It signals, how much longer the frame duration of the current frame
2579 * is compared to normal frame duration.
2580 *
2581 * frame_duration = (1 + repeat_pict) * time_base
2582 *
2583 * It is used by codecs like H.264 to display telecined material.
2584 */
2585 int repeat_pict; /* XXX: Put it back in AVCodecContext. */
2586 int64_t pts; /* pts of the current frame */
2587 int64_t dts; /* dts of the current frame */
2588
2589 /* private data */
2590 int64_t last_pts;
2591 int64_t last_dts;
2592 int fetch_timestamp;
2593
2594#define AV_PARSER_PTS_NB 4
2595 int cur_frame_start_index;
2596 int64_t cur_frame_offset[AV_PARSER_PTS_NB];
2597 int64_t cur_frame_pts[AV_PARSER_PTS_NB];
2598 int64_t cur_frame_dts[AV_PARSER_PTS_NB];
2599
2600 int flags;
2601#define PARSER_FLAG_COMPLETE_FRAMES 0x0001
2602#define PARSER_FLAG_ONCE 0x0002
2603/// Set if the parser has a valid file offset
2604#define PARSER_FLAG_FETCHED_OFFSET 0x0004
2605#define PARSER_FLAG_USE_CODEC_TS 0x1000
2606
2607 int64_t offset; ///< byte offset from starting packet start
2608 int64_t cur_frame_end[AV_PARSER_PTS_NB];
2609
2610 /**
2611 * Set by parser to 1 for key frames and 0 for non-key frames.
2612 * It is initialized to -1, so if the parser doesn't set this flag,
2613 * old-style fallback using AV_PICTURE_TYPE_I picture type as key frames
2614 * will be used.
2615 */
2616 int key_frame;
2617
2618 // Timestamp generation support:
2619 /**
2620 * Synchronization point for start of timestamp generation.
2621 *
2622 * Set to >0 for sync point, 0 for no sync point and <0 for undefined
2623 * (default).
2624 *
2625 * For example, this corresponds to presence of H.264 buffering period
2626 * SEI message.
2627 */
2628 int dts_sync_point;
2629
2630 /**
2631 * Offset of the current timestamp against last timestamp sync point in
2632 * units of AVCodecContext.time_base.
2633 *
2634 * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
2635 * contain a valid timestamp offset.
2636 *
2637 * Note that the timestamp of sync point has usually a nonzero
2638 * dts_ref_dts_delta, which refers to the previous sync point. Offset of
2639 * the next frame after timestamp sync point will be usually 1.
2640 *
2641 * For example, this corresponds to H.264 cpb_removal_delay.
2642 */
2643 int dts_ref_dts_delta;
2644
2645 /**
2646 * Presentation delay of current frame in units of AVCodecContext.time_base.
2647 *
2648 * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
2649 * contain valid non-negative timestamp delta (presentation time of a frame
2650 * must not lie in the past).
2651 *
2652 * This delay represents the difference between decoding and presentation
2653 * time of the frame.
2654 *
2655 * For example, this corresponds to H.264 dpb_output_delay.
2656 */
2657 int pts_dts_delta;
2658
2659 /**
2660 * Position of the packet in file.
2661 *
2662 * Analogous to cur_frame_pts/dts
2663 */
2664 int64_t cur_frame_pos[AV_PARSER_PTS_NB];
2665
2666 /**
2667 * Byte position of currently parsed frame in stream.
2668 */
2669 int64_t pos;
2670
2671 /**
2672 * Previous frame byte position.
2673 */
2674 int64_t last_pos;
2675
2676 /**
2677 * Duration of the current frame.
2678 * For audio, this is in units of 1 / AVCodecContext.sample_rate.
2679 * For all other types, this is in units of AVCodecContext.time_base.
2680 */
2681 int duration;
2682
2683 enum AVFieldOrder field_order;
2684
2685 /**
2686 * Indicate whether a picture is coded as a frame, top field or bottom field.
2687 *
2688 * For example, H.264 field_pic_flag equal to 0 corresponds to
2689 * AV_PICTURE_STRUCTURE_FRAME. An H.264 picture with field_pic_flag
2690 * equal to 1 and bottom_field_flag equal to 0 corresponds to
2691 * AV_PICTURE_STRUCTURE_TOP_FIELD.
2692 */
2693 enum AVPictureStructure picture_structure;
2694
2695 /**
2696 * Picture number incremented in presentation or output order.
2697 * This field may be reinitialized at the first picture of a new sequence.
2698 *
2699 * For example, this corresponds to H.264 PicOrderCnt.
2700 */
2701 int output_picture_number;
2702
2703 /**
2704 * Dimensions of the decoded video intended for presentation.
2705 */
2706 int width;
2707 int height;
2708
2709 /**
2710 * Dimensions of the coded video.
2711 */
2712 int coded_width;
2713 int coded_height;
2714
2715 /**
2716 * The format of the coded data, corresponds to enum AVPixelFormat for video
2717 * and for enum AVSampleFormat for audio.
2718 *
2719 * Note that a decoder can have considerable freedom in how exactly it
2720 * decodes the data, so the format reported here might be different from the
2721 * one returned by a decoder.
2722 */
2723 int format;
2724} AVCodecParserContext;
2725
2726typedef struct AVCodecParser {
2727 int codec_ids[7]; /* several codec IDs are permitted */
2728 int priv_data_size;
2729 int (*parser_init)(AVCodecParserContext *s);
2730 /* This callback never returns an error, a negative value means that
2731 * the frame start was in a previous packet. */
2732 int (*parser_parse)(AVCodecParserContext *s,
2733 AVCodecContext *avctx,
2734 const uint8_t **poutbuf, int *poutbuf_size,
2735 const uint8_t *buf, int buf_size);
2736 void (*parser_close)(AVCodecParserContext *s);
2737 int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
2738} AVCodecParser;
2739
2740/**
2741 * Iterate over all registered codec parsers.
2742 *
2743 * @param opaque a pointer where libavcodec will store the iteration state. Must
2744 * point to NULL to start the iteration.
2745 *
2746 * @return the next registered codec parser or NULL when the iteration is
2747 * finished
2748 */
2749const AVCodecParser *av_parser_iterate(void **opaque);
2750
2751AVCodecParserContext *av_parser_init(int codec_id);
2752
2753/**
2754 * Parse a packet.
2755 *
2756 * @param s parser context.
2757 * @param avctx codec context.
2758 * @param poutbuf set to pointer to parsed buffer or NULL if not yet finished.
2759 * @param poutbuf_size set to size of parsed buffer or zero if not yet finished.
2760 * @param buf input buffer.
2761 * @param buf_size buffer size in bytes without the padding. I.e. the full buffer
2762 size is assumed to be buf_size + AV_INPUT_BUFFER_PADDING_SIZE.
2763 To signal EOF, this should be 0 (so that the last frame
2764 can be output).
2765 * @param pts input presentation timestamp.
2766 * @param dts input decoding timestamp.
2767 * @param pos input byte position in stream.
2768 * @return the number of bytes of the input bitstream used.
2769 *
2770 * Example:
2771 * @code
2772 * while(in_len){
2773 * len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
2774 * in_data, in_len,
2775 * pts, dts, pos);
2776 * in_data += len;
2777 * in_len -= len;
2778 *
2779 * if(size)
2780 * decode_frame(data, size);
2781 * }
2782 * @endcode
2783 */
2784int av_parser_parse2(AVCodecParserContext *s,
2785 AVCodecContext *avctx,
2786 uint8_t **poutbuf, int *poutbuf_size,
2787 const uint8_t *buf, int buf_size,
2788 int64_t pts, int64_t dts,
2789 int64_t pos);
2790
2791void av_parser_close(AVCodecParserContext *s);
2792
2793/**
2794 * @}
2795 * @}
2796 */
2797
2798/**
2799 * @addtogroup lavc_encoding
2800 * @{
2801 */
2802
2803int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
2804 const AVSubtitle *sub);
2805
2806
2807/**
2808 * @}
2809 */
2810
2811/**
2812 * @defgroup lavc_misc Utility functions
2813 * @ingroup libavc
2814 *
2815 * Miscellaneous utility functions related to both encoding and decoding
2816 * (or neither).
2817 * @{
2818 */
2819
2820/**
2821 * @defgroup lavc_misc_pixfmt Pixel formats
2822 *
2823 * Functions for working with pixel formats.
2824 * @{
2825 */
2826
2827/**
2828 * Return a value representing the fourCC code associated to the
2829 * pixel format pix_fmt, or 0 if no associated fourCC code can be
2830 * found.
2831 */
2832unsigned int avcodec_pix_fmt_to_codec_tag(enum AVPixelFormat pix_fmt);
2833
2834/**
2835 * Find the best pixel format to convert to given a certain source pixel
2836 * format. When converting from one pixel format to another, information loss
2837 * may occur. For example, when converting from RGB24 to GRAY, the color
2838 * information will be lost. Similarly, other losses occur when converting from
2839 * some formats to other formats. avcodec_find_best_pix_fmt_of_2() searches which of
2840 * the given pixel formats should be used to suffer the least amount of loss.
2841 * The pixel formats from which it chooses one, are determined by the
2842 * pix_fmt_list parameter.
2843 *
2844 *
2845 * @param[in] pix_fmt_list AV_PIX_FMT_NONE terminated array of pixel formats to choose from
2846 * @param[in] src_pix_fmt source pixel format
2847 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
2848 * @param[out] loss_ptr Combination of flags informing you what kind of losses will occur.
2849 * @return The best pixel format to convert to or -1 if none was found.
2850 */
2851enum AVPixelFormat avcodec_find_best_pix_fmt_of_list(const enum AVPixelFormat *pix_fmt_list,
2852 enum AVPixelFormat src_pix_fmt,
2853 int has_alpha, int *loss_ptr);
2854
2855enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
2856
2857/**
2858 * @}
2859 */
2860
2861void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);
2862
2863int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size);
2864int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count);
2865//FIXME func typedef
2866
2867/**
2868 * Fill AVFrame audio data and linesize pointers.
2869 *
2870 * The buffer buf must be a preallocated buffer with a size big enough
2871 * to contain the specified samples amount. The filled AVFrame data
2872 * pointers will point to this buffer.
2873 *
2874 * AVFrame extended_data channel pointers are allocated if necessary for
2875 * planar audio.
2876 *
2877 * @param frame the AVFrame
2878 * frame->nb_samples must be set prior to calling the
2879 * function. This function fills in frame->data,
2880 * frame->extended_data, frame->linesize[0].
2881 * @param nb_channels channel count
2882 * @param sample_fmt sample format
2883 * @param buf buffer to use for frame data
2884 * @param buf_size size of buffer
2885 * @param align plane size sample alignment (0 = default)
2886 * @return >=0 on success, negative error code on failure
2887 * @todo return the size in bytes required to store the samples in
2888 * case of success, at the next libavutil bump
2889 */
2890int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
2891 enum AVSampleFormat sample_fmt, const uint8_t *buf,
2892 int buf_size, int align);
2893
2894/**
2895 * Reset the internal codec state / flush internal buffers. Should be called
2896 * e.g. when seeking or when switching to a different stream.
2897 *
2898 * @note for decoders, this function just releases any references the decoder
2899 * might keep internally, but the caller's references remain valid.
2900 *
2901 * @note for encoders, this function will only do something if the encoder
2902 * declares support for AV_CODEC_CAP_ENCODER_FLUSH. When called, the encoder
2903 * will drain any remaining packets, and can then be reused for a different
2904 * stream (as opposed to sending a null frame which will leave the encoder
2905 * in a permanent EOF state after draining). This can be desirable if the
2906 * cost of tearing down and replacing the encoder instance is high.
2907 */
2908void avcodec_flush_buffers(AVCodecContext *avctx);
2909
2910/**
2911 * Return audio frame duration.
2912 *
2913 * @param avctx codec context
2914 * @param frame_bytes size of the frame, or 0 if unknown
2915 * @return frame duration, in samples, if known. 0 if not able to
2916 * determine.
2917 */
2918int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
2919
2920/* memory */
2921
2922/**
2923 * Same behaviour av_fast_malloc but the buffer has additional
2924 * AV_INPUT_BUFFER_PADDING_SIZE at the end which will always be 0.
2925 *
2926 * In addition the whole buffer will initially and after resizes
2927 * be 0-initialized so that no uninitialized data will ever appear.
2928 */
2929void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size);
2930
2931/**
2932 * Same behaviour av_fast_padded_malloc except that buffer will always
2933 * be 0-initialized after call.
2934 */
2935void av_fast_padded_mallocz(void *ptr, unsigned int *size, size_t min_size);
2936
2937/**
2938 * @return a positive value if s is open (i.e. avcodec_open2() was called on it),
2939 * 0 otherwise.
2940 */
2941int avcodec_is_open(AVCodecContext *s);
2942
2943/**
2944 * @}
2945 */
2946
2947#endif /* AVCODEC_AVCODEC_H */
2948