aboutsummaryrefslogtreecommitdiffstats
path: root/libavutil/frame.h
blob: 18e239f87054d34e4d344527a5efc061229932aa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * @ingroup lavu_frame
 * reference-counted frame API
 */

#ifndef AVUTIL_FRAME_H
#define AVUTIL_FRAME_H

#include <stddef.h>
#include <stdint.h>

#include "avutil.h"
#include "buffer.h"
#include "dict.h"
#include "rational.h"
#include "samplefmt.h"
#include "pixfmt.h"
#include "version.h"


/**
 * @defgroup lavu_frame AVFrame
 * @ingroup lavu_data
 *
 * @{
 * AVFrame is an abstraction for reference-counted raw multimedia data.
 */

enum AVFrameSideDataType {
    /**
     * The data is the AVPanScan struct defined in libavcodec.
     */
    AV_FRAME_DATA_PANSCAN,
    /**
     * ATSC A53 Part 4 Closed Captions.
     * A53 CC bitstream is stored as uint8_t in AVFrameSideData.data.
     * The number of bytes of CC data is AVFrameSideData.size.
     */
    AV_FRAME_DATA_A53_CC,
    /**
     * Stereoscopic 3d metadata.
     * The data is the AVStereo3D struct defined in libavutil/stereo3d.h.
     */
    AV_FRAME_DATA_STEREO3D,
    /**
     * The data is the AVMatrixEncoding enum defined in libavutil/channel_layout.h.
     */
    AV_FRAME_DATA_MATRIXENCODING,
    /**
     * Metadata relevant to a downmix procedure.
     * The data is the AVDownmixInfo struct defined in libavutil/downmix_info.h.
     */
    AV_FRAME_DATA_DOWNMIX_INFO,
    /**
     * ReplayGain information in the form of the AVReplayGain struct.
     */
    AV_FRAME_DATA_REPLAYGAIN,
    /**
     * This side data contains a 3x3 transformation matrix describing an affine
     * transformation that needs to be applied to the frame for correct
     * presentation.
     *
     * See libavutil/display.h for a detailed description of the data.
     */
    AV_FRAME_DATA_DISPLAYMATRIX,
    /**
     * Active Format Description data consisting of a single byte as specified
     * in ETSI TS 101 154 using AVActiveFormatDescription enum.
     */
    AV_FRAME_DATA_AFD,
    /**
     * Motion vectors exported by some codecs (on demand through the export_mvs
     * flag set in the libavcodec AVCodecContext flags2 option).
     * The data is the AVMotionVector struct defined in
     * libavutil/motion_vector.h.
     */
    AV_FRAME_DATA_MOTION_VECTORS,
    /**
     * Recommmends skipping the specified number of samples. This is exported
     * only if the "skip_manual" AVOption is set in libavcodec.
     * This has the same format as AV_PKT_DATA_SKIP_SAMPLES.
     * @code
     * u32le number of samples to skip from start of this packet
     * u32le number of samples to skip from end of this packet
     * u8    reason for start skip
     * u8    reason for end   skip (0=padding silence, 1=convergence)
     * @endcode
     */
    AV_FRAME_DATA_SKIP_SAMPLES,
    /**
     * This side data must be associated with an audio frame and corresponds to
     * enum AVAudioServiceType defined in avcodec.h.
     */
    AV_FRAME_DATA_AUDIO_SERVICE_TYPE,
    /**
     * Mastering display metadata associated with a video frame. The payload is
     * an AVMasteringDisplayMetadata type and contains information about the
     * mastering display color volume.
     */
    AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
    /**
     * The GOP timecode in 25 bit timecode format. Data format is 64-bit integer.
     * This is set on the first frame of a GOP that has a temporal reference of 0.
     */
    AV_FRAME_DATA_GOP_TIMECODE,

    /**
     * The data represents the AVSphericalMapping structure defined in
     * libavutil/spherical.h.
     */
    AV_FRAME_DATA_SPHERICAL,

    /**
     * Content light level (based on CTA-861.3). This payload contains data in
     * the form of the AVContentLightMetadata struct.
     */
    AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,

    /**
     * The data contains an ICC profile as an opaque octet buffer following the
     * format described by ISO 15076-1 with an optional name defined in the
     * metadata key entry "name".
     */
    AV_FRAME_DATA_ICC_PROFILE,

    /**
     * Timecode which conforms to SMPTE ST 12-1. The data is an array of 4 uint32_t
     * where the first uint32_t describes how many (1-3) of the other timecodes are used.
     * The timecode format is described in the documentation of av_timecode_get_smpte_from_framenum()
     * function in libavutil/timecode.h.
     */
    AV_FRAME_DATA_S12M_TIMECODE,

    /**
     * HDR dynamic metadata associated with a video frame. The payload is
     * an AVDynamicHDRPlus type and contains information for color
     * volume transform - application 4 of SMPTE 2094-40:2016 standard.
     */
    AV_FRAME_DATA_DYNAMIC_HDR_PLUS,

    /**
     * Regions Of Interest, the data is an array of AVRegionOfInterest type, the number of
     * array element is implied by AVFrameSideData.size / AVRegionOfInterest.self_size.
     */
    AV_FRAME_DATA_REGIONS_OF_INTEREST,

    /**
     * Encoding parameters for a video frame, as described by AVVideoEncParams.
     */
    AV_FRAME_DATA_VIDEO_ENC_PARAMS,

    /**
     * User data unregistered metadata associated with a video frame.
     * This is the H.26[45] UDU SEI message, and shouldn't be used for any other purpose
     * The data is stored as uint8_t in AVFrameSideData.data which is 16 bytes of
     * uuid_iso_iec_11578 followed by AVFrameSideData.size - 16 bytes of user_data_payload_byte.
     */
    AV_FRAME_DATA_SEI_UNREGISTERED,

    /**
     * Film grain parameters for a frame, described by AVFilmGrainParams.
     * Must be present for every frame which should have film grain applied.
     */
    AV_FRAME_DATA_FILM_GRAIN_PARAMS,

    /**
     * Bounding boxes for object detection and classification,
     * as described by AVDetectionBBoxHeader.
     */
    AV_FRAME_DATA_DETECTION_BBOXES,

    /**
     * Dolby Vision RPU raw data, suitable for passing to x265
     * or other libraries. Array of uint8_t, with NAL emulation
     * bytes intact.
     */
    AV_FRAME_DATA_DOVI_RPU_BUFFER,

    /**
     * Parsed Dolby Vision metadata, suitable for passing to a software
     * implementation. The payload is the AVDOVIMetadata struct defined in
     * libavutil/dovi_meta.h.
     */
    AV_FRAME_DATA_DOVI_METADATA,
};

enum AVActiveFormatDescription {
    AV_AFD_SAME         = 8,
    AV_AFD_4_3          = 9,
    AV_AFD_16_9         = 10,
    AV_AFD_14_9         = 11,
    AV_AFD_4_3_SP_14_9  = 13,
    AV_AFD_16_9_SP_14_9 = 14,
    AV_AFD_SP_4_3       = 15,
};


/**
 * Structure to hold side data for an AVFrame.
 *
 * sizeof(AVFrameSideData) is not a part of the public ABI, so new fields may be added
 * to the end with a minor bump.
 */
typedef struct AVFrameSideData {
    enum AVFrameSideDataType type;
    uint8_t *data;
    size_t   size;
    AVDictionary *metadata;
    AVBufferRef *buf;
} AVFrameSideData;

/**
 * Structure describing a single Region Of Interest.
 *
 * When multiple regions are defined in a single side-data block, they
 * should be ordered from most to least important - some encoders are only
 * capable of supporting a limited number of distinct regions, so will have
 * to truncate the list.
 *
 * When overlapping regions are defined, the first region containing a given
 * area of the frame applies.
 */
typedef struct AVRegionOfInterest {
    /**
     * Must be set to the size of this data structure (that is,
     * sizeof(AVRegionOfInterest)).
     */
    uint32_t self_size;
    /**
     * Distance in pixels from the top edge of the frame to the top and
     * bottom edges and from the left edge of the frame to the left and
     * right edges of the rectangle defining this region of interest.
     *
     * The constraints on a region are encoder dependent, so the region
     * actually affected may be slightly larger for alignment or other
     * reasons.
     */
    int top;
    int bottom;
    int left;
    int right;
    /**
     * Quantisation offset.
     *
     * Must be in the range -1 to +1.  A value of zero indicates no quality
     * change.  A negative value asks for better quality (less quantisation),
     * while a positive value asks for worse quality (greater quantisation).
     *
     * The range is calibrated so that the extreme values indicate the
     * largest possible offset - if the rest of the frame is encoded with the
     * worst possible quality, an offset of -1 indicates that this region
     * should be encoded with the best possible quality anyway.  Intermediate
     * values are then interpolated in some codec-dependent way.
     *
     * For example, in 10-bit H.264 the quantisation parameter varies between
     * -12 and 51.  A typical qoffset value of -1/10 therefore indicates that
     * this region should be encoded with a QP around one-tenth of the full
     * range better than the rest of the frame.  So, if most of the frame
     * were to be encoded with a QP of around 30, this region would get a QP
     * of around 24 (an offset of approximately -1/10 * (51 - -12) = -6.3).
     * An extreme value of -1 would indicate that this region should be
     * encoded with the best possible quality regardless of the treatment of
     * the rest of the frame - that is, should be encoded at a QP of -12.
     */
    AVRational qoffset;
} AVRegionOfInterest;

/**
 * This structure describes decoded (raw) audio or video data.
 *
 * AVFrame must be allocated using av_frame_alloc(). Note that this only
 * allocates the AVFrame itself, the buffers for the data must be managed
 * through other means (see below).
 * AVFrame must be freed with av_frame_free().
 *
 * AVFrame is typically allocated once and then reused multiple times to hold
 * different data (e.g. a single AVFrame to hold frames received from a
 * decoder). In such a case, av_frame_unref() will free any references held by
 * the frame and reset it to its original clean state before it
 * is reused again.
 *
 * The data described by an AVFrame is usually reference counted through the
 * AVBuffer API. The underlying buffer references are stored in AVFrame.buf /
 * AVFrame.extended_buf. An AVFrame is considered to be reference counted if at
 * least one reference is set, i.e. if AVFrame.buf[0] != NULL. In such a case,
 * every single data plane must be contained in one of the buffers in
 * AVFrame.buf or AVFrame.extended_buf.
 * There may be a single buffer for all the data, or one separate buffer for
 * each plane, or anything in between.
 *
 * sizeof(AVFrame) is not a part of the public ABI, so new fields may be added
 * to the end with a minor bump.
 *
 * Fields can be accessed through AVOptions, the name string used, matches the
 * C structure field name for fields accessible through AVOptions. The AVClass
 * for AVFrame can be obtained from avcodec_get_frame_class()
 */
typedef struct AVFrame {
#define AV_NUM_DATA_POINTERS 8
    /**
     * pointer to the picture/channel planes.
     * This might be different from the first allocated byte. For video,
     * it could even point to the end of the image data.
     *
     * All pointers in data and extended_data must point into one of the
     * AVBufferRef in buf or extended_buf.
     *
     * Some decoders access areas outside 0,0 - width,height, please
     * see avcodec_align_dimensions2(). Some filters and swscale can read
     * up to 16 bytes beyond the planes, if these filters are to be used,
     * then 16 extra bytes must be allocated.
     *
     * NOTE: Pointers not needed by the format MUST be set to NULL.
     *
     * @attention In case of video, the data[] pointers can point to the
     * end of image data in order to reverse line order, when used in
     * combination with negative values in the linesize[] array.
     */
    uint8_t *data[AV_NUM_DATA_POINTERS];

    /**
     * For video, a positive or negative value, which is typically indicating
     * the size in bytes of each picture line, but it can also be:
     * - the negative byte size of lines for vertical flipping
     *   (with data[n] pointing to the end of the data
     * - a positive or negative multiple of the byte size as for accessing
     *   even and odd fields of a frame (possibly flipped)
     *
     * For audio, only linesize[0] may be set. For planar audio, each channel
     * plane must be the same size.
     *
     * For video the linesizes should be multiples of the CPUs alignment
     * preference, this is 16 or 32 for modern desktop CPUs.
     * Some code requires such alignment other code can be slower without
     * correct alignment, for yet other it makes no difference.
     *
     * @note The linesize may be larger than the size of usable data -- there
     * may be extra padding present for performance reasons.
     *
     * @attention In case of video, line size values can be negative to achieve
     * a vertically inverted iteration over image lines.
     */
    int linesize[AV_NUM_DATA_POINTERS];

    /**
     * pointers to the data planes/channels.
     *
     * For video, this should simply point to data[].
     *
     * For planar audio, each channel has a separate data pointer, and
     * linesize[0] contains the size of each channel buffer.
     * For packed audio, there is just one data pointer, and linesize[0]
     * contains the total size of the buffer for all channels.
     *
     * Note: Both data and extended_data should always be set in a valid frame,
     * but for planar audio with more channels that can fit in data,
     * extended_data must be used in order to access all channels.
     */
    uint8_t **extended_data;

    /**
     * @name Video dimensions
     * Video frames only. The coded dimensions (in pixels) of the video frame,
     * i.e. the size of the rectangle that contains some well-defined values.
     *
     * @note The part of the frame intended for display/presentation is further
     * restricted by the @ref cropping "Cropping rectangle".
     * @{
     */
    int width, height;
    /**
     * @}
     */

    /**
     * number of audio samples (per channel) described by this frame
     */
    int nb_samples;

    /**
     * format of the frame, -1 if unknown or unset
     * Values correspond to enum AVPixelFormat for video frames,
     * enum AVSampleFormat for audio)
     */
    int format;

    /**
     * 1 -> keyframe, 0-> not
     */
    int key_frame;

    /**
     * Picture type of the frame.
     */
    enum AVPictureType pict_type;

    /**
     * Sample aspect ratio for the video frame, 0/1 if unknown/unspecified.
     */
    AVRational sample_aspect_ratio;

    /**
     * Presentation timestamp in time_base units (time when frame should be shown to user).
     */
    int64_t pts;

    /**
     * DTS copied from the AVPacket that triggered returning this frame. (if frame threading isn't used)
     * This is also the Presentation time of this AVFrame calculated from
     * only AVPacket.dts values without pts values.
     */
    int64_t pkt_dts;

    /**
     * Time base for the timestamps in this frame.
     * In the future, this field may be set on frames output by decoders or
     * filters, but its value will be by default ignored on input to encoders
     * or filters.
     */
    AVRational time_base;

    /**
     * picture number in bitstream order
     */
    int coded_picture_number;
    /**
     * picture number in display order
     */
    int display_picture_number;

    /**
     * quality (between 1 (good) and FF_LAMBDA_MAX (bad))
     */
    int quality;

    /**
     * for some private data of the user
     */
    void *opaque;

    /**
     * When decoding, this signals how much the picture must be delayed.
     * extra_delay = repeat_pict / (2*fps)
     */
    int repeat_pict;

    /**
     * The content of the picture is interlaced.
     */
    int interlaced_frame;

    /**
     * If the content is interlaced, is top field displayed first.
     */
    int top_field_first;

    /**
     * Tell user application that palette has changed from previous frame.
     */
    int palette_has_changed;

    /**
     * reordered opaque 64 bits (generally an integer or a double precision float
     * PTS but can be anything).
     * The user sets AVCodecContext.reordered_opaque to represent the input at
     * that time,
     * the decoder reorders values as needed and sets AVFrame.reordered_opaque
     * to exactly one of the values provided by the user through AVCodecContext.reordered_opaque
     */
    int64_t reordered_opaque;

    /**
     * Sample rate of the audio data.
     */
    int sample_rate;

    /**
     * Channel layout of the audio data.
     */
    uint64_t channel_layout;

    /**
     * AVBuffer references backing the data for this frame. All the pointers in
     * data and extended_data must point inside one of the buffers in buf or
     * extended_buf. This array must be filled contiguously -- if buf[i] is
     * non-NULL then buf[j] must also be non-NULL for all j < i.
     *
     * There may be at most one AVBuffer per data plane, so for video this array
     * always contains all the references. For planar audio with more than
     * AV_NUM_DATA_POINTERS channels, there may be more buffers than can fit in
     * this array. Then the extra AVBufferRef pointers are stored in the
     * extended_buf array.
     */
    AVBufferRef *buf[AV_NUM_DATA_POINTERS];

    /**
     * For planar audio which requires more than AV_NUM_DATA_POINTERS
     * AVBufferRef pointers, this array will hold all the references which
     * cannot fit into AVFrame.buf.
     *
     * Note that this is different from AVFrame.extended_data, which always
     * contains all the pointers. This array only contains the extra pointers,
     * which cannot fit into AVFrame.buf.
     *
     * This array is always allocated using av_malloc() by whoever constructs
     * the frame. It is freed in av_frame_unref().
     */
    AVBufferRef **extended_buf;
    /**
     * Number of elements in extended_buf.
     */
    int        nb_extended_buf;

    AVFrameSideData **side_data;
    int            nb_side_data;

/**
 * @defgroup lavu_frame_flags AV_FRAME_FLAGS
 * @ingroup lavu_frame
 * Flags describing additional frame properties.
 *
 * @{
 */

/**
 * The frame data may be corrupted, e.g. due to decoding errors.
 */
#define AV_FRAME_FLAG_CORRUPT       (1 << 0)
/**
 * A flag to mark the frames which need to be decoded, but shouldn't be output.
 */
#define AV_FRAME_FLAG_DISCARD   (1 << 2)
/**
 * @}
 */

    /**
     * Frame flags, a combination of @ref lavu_frame_flags
     */
    int flags;

    /**
     * MPEG vs JPEG YUV range.
     * - encoding: Set by user
     * - decoding: Set by libavcodec
     */
    enum AVColorRange color_range;

    enum AVColorPrimaries color_primaries;

    enum AVColorTransferCharacteristic color_trc;

    /**
     * YUV colorspace type.
     * - encoding: Set by user
     * - decoding: Set by libavcodec
     */
    enum AVColorSpace colorspace;

    enum AVChromaLocation chroma_location;

    /**
     * frame timestamp estimated using various heuristics, in stream time base
     * - encoding: unused
     * - decoding: set by libavcodec, read by user.
     */
    int64_t best_effort_timestamp;

    /**
     * reordered pos from the last AVPacket that has been input into the decoder
     * - encoding: unused
     * - decoding: Read by user.
     */
    int64_t pkt_pos;

    /**
     * duration of the corresponding packet, expressed in
     * AVStream->time_base units, 0 if unknown.
     * - encoding: unused
     * - decoding: Read by user.
     */
    int64_t pkt_duration;

    /**
     * metadata.
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    AVDictionary *metadata;

    /**
     * decode error flags of the frame, set to a combination of
     * FF_DECODE_ERROR_xxx flags if the decoder produced a frame, but there
     * were errors during the decoding.
     * - encoding: unused
     * - decoding: set by libavcodec, read by user.
     */
    int decode_error_flags;
#define FF_DECODE_ERROR_INVALID_BITSTREAM   1
#define FF_DECODE_ERROR_MISSING_REFERENCE   2
#define FF_DECODE_ERROR_CONCEALMENT_ACTIVE  4
#define FF_DECODE_ERROR_DECODE_SLICES       8

    /**
     * number of audio channels, only used for audio.
     * - encoding: unused
     * - decoding: Read by user.
     */
    int channels;

    /**
     * size of the corresponding packet containing the compressed
     * frame.
     * It is set to a negative value if unknown.
     * - encoding: unused
     * - decoding: set by libavcodec, read by user.
     */
    int pkt_size;

    /**
     * For hwaccel-format frames, this should be a reference to the
     * AVHWFramesContext describing the frame.
     */
    AVBufferRef *hw_frames_ctx;

    /**
     * AVBufferRef for free use by the API user. FFmpeg will never check the
     * contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
     * the frame is unreferenced. av_frame_copy_props() calls create a new
     * reference with av_buffer_ref() for the target frame's opaque_ref field.
     *
     * This is unrelated to the opaque field, although it serves a similar
     * purpose.
     */
    AVBufferRef *opaque_ref;

    /**
     * @anchor cropping
     * @name Cropping
     * Video frames only. The number of pixels to discard from the the
     * top/bottom/left/right border of the frame to obtain the sub-rectangle of
     * the frame intended for presentation.
     * @{
     */
    size_t crop_top;
    size_t crop_bottom;
    size_t crop_left;
    size_t crop_right;
    /**
     * @}
     */

    /**
     * AVBufferRef for internal use by a single libav* library.
     * Must not be used to transfer data between libraries.
     * Has to be NULL when ownership of the frame leaves the respective library.
     *
     * Code outside the FFmpeg libs should never check or change the contents of the buffer ref.
     *
     * FFmpeg calls av_buffer_unref() on it when the frame is unreferenced.
     * av_frame_copy_props() calls create a new reference with av_buffer_ref()
     * for the target frame's private_ref field.
     */
    AVBufferRef *private_ref;
} AVFrame;


#if FF_API_COLORSPACE_NAME
/**
 * Get the name of a colorspace.
 * @return a static string identifying the colorspace; can be NULL.
 * @deprecated use av_color_space_name()
 */
attribute_deprecated
const char *av_get_colorspace_name(enum AVColorSpace val);
#endif
/**
 * Allocate an AVFrame and set its fields to default values.  The resulting
 * struct must be freed using av_frame_free().
 *
 * @return An AVFrame filled with default values or NULL on failure.
 *
 * @note this only allocates the AVFrame itself, not the data buffers. Those
 * must be allocated through other means, e.g. with av_frame_get_buffer() or
 * manually.
 */
AVFrame *av_frame_alloc(void);

/**
 * Free the frame and any dynamically allocated objects in it,
 * e.g. extended_data. If the frame is reference counted, it will be
 * unreferenced first.
 *
 * @param frame frame to be freed. The pointer will be set to NULL.
 */
void av_frame_free(AVFrame **frame);

/**
 * Set up a new reference to the data described by the source frame.
 *
 * Copy frame properties from src to dst and create a new reference for each
 * AVBufferRef from src.
 *
 * If src is not reference counted, new buffers are allocated and the data is
 * copied.
 *
 * @warning: dst MUST have been either unreferenced with av_frame_unref(dst),
 *           or newly allocated with av_frame_alloc() before calling this
 *           function, or undefined behavior will occur.
 *
 * @return 0 on success, a negative AVERROR on error
 */
int av_frame_ref(AVFrame *dst, const AVFrame *src);

/**
 * Create a new frame that references the same data as src.
 *
 * This is a shortcut for av_frame_alloc()+av_frame_ref().
 *
 * @return newly created AVFrame on success, NULL on error.
 */
AVFrame *av_frame_clone(const AVFrame *src);

/**
 * Unreference all the buffers referenced by frame and reset the frame fields.
 */
void av_frame_unref(AVFrame *frame);

/**
 * Move everything contained in src to dst and reset src.
 *
 * @warning: dst is not unreferenced, but directly overwritten without reading
 *           or deallocating its contents. Call av_frame_unref(dst) manually
 *           before calling this function to ensure that no memory is leaked.
 */
void av_frame_move_ref(AVFrame *dst, AVFrame *src);

/**
 * Allocate new buffer(s) for audio or video data.
 *
 * The following fields must be set on frame before calling this function:
 * - format (pixel format for video, sample format for audio)
 * - width and height for video
 * - nb_samples and channel_layout for audio
 *
 * This function will fill AVFrame.data and AVFrame.buf arrays and, if
 * necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
 * For planar formats, one buffer will be allocated for each plane.
 *
 * @warning: if frame already has been allocated, calling this function will
 *           leak memory. In addition, undefined behavior can occur in certain
 *           cases.
 *
 * @param frame frame in which to store the new buffers.
 * @param align Required buffer size alignment. If equal to 0, alignment will be
 *              chosen automatically for the current CPU. It is highly
 *              recommended to pass 0 here unless you know what you are doing.
 *
 * @return 0 on success, a negative AVERROR on error.
 */
int av_frame_get_buffer(AVFrame *frame, int align);

/**
 * Check if the frame data is writable.
 *
 * @return A positive value if the frame data is writable (which is true if and
 * only if each of the underlying buffers has only one reference, namely the one
 * stored in this frame). Return 0 otherwise.
 *
 * If 1 is returned the answer is valid until av_buffer_ref() is called on any
 * of the underlying AVBufferRefs (e.g. through av_frame_ref() or directly).
 *
 * @see av_frame_make_writable(), av_buffer_is_writable()
 */
int av_frame_is_writable(AVFrame *frame);

/**
 * Ensure that the frame data is writable, avoiding data copy if possible.
 *
 * Do nothing if the frame is writable, allocate new buffers and copy the data
 * if it is not.
 *
 * @return 0 on success, a negative AVERROR on error.
 *
 * @see av_frame_is_writable(), av_buffer_is_writable(),
 * av_buffer_make_writable()
 */
int av_frame_make_writable(AVFrame *frame);

/**
 * Copy the frame data from src to dst.
 *
 * This function does not allocate anything, dst must be already initialized and
 * allocated with the same parameters as src.
 *
 * This function only copies the frame data (i.e. the contents of the data /
 * extended data arrays), not any other properties.
 *
 * @return >= 0 on success, a negative AVERROR on error.
 */
int av_frame_copy(AVFrame *dst, const AVFrame *src);

/**
 * Copy only "metadata" fields from src to dst.
 *
 * Metadata for the purpose of this function are those fields that do not affect
 * the data layout in the buffers.  E.g. pts, sample rate (for audio) or sample
 * aspect ratio (for video), but not width/height or channel layout.
 * Side data is also copied.
 */
int av_frame_copy_props(AVFrame *dst, const AVFrame *src);

/**
 * Get the buffer reference a given data plane is stored in.
 *
 * @param plane index of the data plane of interest in frame->extended_data.
 *
 * @return the buffer reference that contains the plane or NULL if the input
 * frame is not valid.
 */
AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane);

/**
 * Add a new side data to a frame.
 *
 * @param frame a frame to which the side data should be added
 * @param type type of the added side data
 * @param size size of the side data
 *
 * @return newly added side data on success, NULL on error
 */
AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
                                        enum AVFrameSideDataType type,
                                        size_t size);

/**
 * Add a new side data to a frame from an existing AVBufferRef
 *
 * @param frame a frame to which the side data should be added
 * @param type  the type of the added side data
 * @param buf   an AVBufferRef to add as side data. The ownership of
 *              the reference is transferred to the frame.
 *
 * @return newly added side data on success, NULL on error. On failure
 *         the frame is unchanged and the AVBufferRef remains owned by
 *         the caller.
 */
AVFrameSideData *av_frame_new_side_data_from_buf(AVFrame *frame,
                                                 enum AVFrameSideDataType type,
                                                 AVBufferRef *buf);

/**
 * @return a pointer to the side data of a given type on success, NULL if there
 * is no side data with such type in this frame.
 */
AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
                                        enum AVFrameSideDataType type);

/**
 * Remove and free all side data instances of the given type.
 */
void av_frame_remove_side_data(AVFrame *frame, enum AVFrameSideDataType type);


/**
 * Flags for frame cropping.
 */
enum {
    /**
     * Apply the maximum possible cropping, even if it requires setting the
     * AVFrame.data[] entries to unaligned pointers. Passing unaligned data
     * to FFmpeg API is generally not allowed, and causes undefined behavior
     * (such as crashes). You can pass unaligned data only to FFmpeg APIs that
     * are explicitly documented to accept it. Use this flag only if you
     * absolutely know what you are doing.
     */
    AV_FRAME_CROP_UNALIGNED     = 1 << 0,
};

/**
 * Crop the given video AVFrame according to its crop_left/crop_top/crop_right/
 * crop_bottom fields. If cropping is successful, the function will adjust the
 * data pointers and the width/height fields, and set the crop fields to 0.
 *
 * In all cases, the cropping boundaries will be rounded to the inherent
 * alignment of the pixel format. In some cases, such as for opaque hwaccel
 * formats, the left/top cropping is ignored. The crop fields are set to 0 even
 * if the cropping was rounded or ignored.
 *
 * @param frame the frame which should be cropped
 * @param flags Some combination of AV_FRAME_CROP_* flags, or 0.
 *
 * @return >= 0 on success, a negative AVERROR on error. If the cropping fields
 * were invalid, AVERROR(ERANGE) is returned, and nothing is changed.
 */
int av_frame_apply_cropping(AVFrame *frame, int flags);

/**
 * @return a string identifying the side data type
 */
const char *av_frame_side_data_name(enum AVFrameSideDataType type);

/**
 * @}
 */

#endif /* AVUTIL_FRAME_H */