aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/h264dec.c
blob: 0154fe17b665842284c5d782ca5c895be098fbec (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
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
/*
 * H.26L/H.264/AVC/JVT/14496-10/... decoder
 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
 *
 * 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
 * H.264 / AVC / MPEG-4 part10 codec.
 * @author Michael Niedermayer <michaelni@gmx.at>
 */

#define UNCHECKED_BITSTREAM_READER 1

#include "config_components.h"

#include "libavutil/avassert.h"
#include "libavutil/emms.h"
#include "libavutil/imgutils.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/thread.h"
#include "libavutil/video_enc_params.h"

#include "codec_internal.h"
#include "internal.h"
#include "error_resilience.h"
#include "avcodec.h"
#include "h264.h"
#include "h264dec.h"
#include "h2645_parse.h"
#include "h264data.h"
#include "h264_ps.h"
#include "golomb.h"
#include "hwaccel_internal.h"
#include "hwconfig.h"
#include "mpegutils.h"
#include "profiles.h"
#include "rectangle.h"
#include "refstruct.h"
#include "thread.h"
#include "threadframe.h"

const uint16_t ff_h264_mb_sizes[4] = { 256, 384, 512, 768 };

int avpriv_h264_has_num_reorder_frames(AVCodecContext *avctx)
{
    H264Context *h = avctx->priv_data;
    return h && h->ps.sps ? h->ps.sps->num_reorder_frames : 0;
}

static void h264_er_decode_mb(void *opaque, int ref, int mv_dir, int mv_type,
                              int (*mv)[2][4][2],
                              int mb_x, int mb_y, int mb_intra, int mb_skipped)
{
    const H264Context *h = opaque;
    H264SliceContext *sl = &h->slice_ctx[0];

    sl->mb_x = mb_x;
    sl->mb_y = mb_y;
    sl->mb_xy = mb_x + mb_y * h->mb_stride;
    memset(sl->non_zero_count_cache, 0, sizeof(sl->non_zero_count_cache));
    av_assert1(ref >= 0);
    /* FIXME: It is possible albeit uncommon that slice references
     * differ between slices. We take the easy approach and ignore
     * it for now. If this turns out to have any relevance in
     * practice then correct remapping should be added. */
    if (ref >= sl->ref_count[0])
        ref = 0;
    if (!sl->ref_list[0][ref].data[0]) {
        av_log(h->avctx, AV_LOG_DEBUG, "Reference not available for error concealing\n");
        ref = 0;
    }
    if ((sl->ref_list[0][ref].reference&3) != 3) {
        av_log(h->avctx, AV_LOG_DEBUG, "Reference invalid\n");
        return;
    }
    fill_rectangle(&h->cur_pic.ref_index[0][4 * sl->mb_xy],
                   2, 2, 2, ref, 1);
    fill_rectangle(&sl->ref_cache[0][scan8[0]], 4, 4, 8, ref, 1);
    fill_rectangle(sl->mv_cache[0][scan8[0]], 4, 4, 8,
                   pack16to32((*mv)[0][0][0], (*mv)[0][0][1]), 4);
    sl->mb_mbaff =
    sl->mb_field_decoding_flag = 0;
    ff_h264_hl_decode_mb(h, &h->slice_ctx[0]);
}

void ff_h264_draw_horiz_band(const H264Context *h, H264SliceContext *sl,
                             int y, int height)
{
    AVCodecContext *avctx = h->avctx;
    const AVFrame   *src  = h->cur_pic.f;
    const AVPixFmtDescriptor *desc;
    int offset[AV_NUM_DATA_POINTERS];
    int vshift;
    const int field_pic = h->picture_structure != PICT_FRAME;

    if (!avctx->draw_horiz_band)
        return;

    if (field_pic && h->first_field && !(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD))
        return;

    if (field_pic) {
        height <<= 1;
        y      <<= 1;
    }

    height = FFMIN(height, avctx->height - y);

    desc   = av_pix_fmt_desc_get(avctx->pix_fmt);
    vshift = desc->log2_chroma_h;

    offset[0] = y * src->linesize[0];
    offset[1] =
    offset[2] = (y >> vshift) * src->linesize[1];
    for (int i = 3; i < AV_NUM_DATA_POINTERS; i++)
        offset[i] = 0;

    emms_c();

    avctx->draw_horiz_band(avctx, src, offset,
                           y, h->picture_structure, height);
}

void ff_h264_free_tables(H264Context *h)
{
    int i;

    av_freep(&h->intra4x4_pred_mode);
    av_freep(&h->chroma_pred_mode_table);
    av_freep(&h->cbp_table);
    av_freep(&h->mvd_table[0]);
    av_freep(&h->mvd_table[1]);
    av_freep(&h->direct_table);
    av_freep(&h->non_zero_count);
    av_freep(&h->slice_table_base);
    h->slice_table = NULL;
    av_freep(&h->list_counts);

    av_freep(&h->mb2b_xy);
    av_freep(&h->mb2br_xy);

    ff_refstruct_pool_uninit(&h->qscale_table_pool);
    ff_refstruct_pool_uninit(&h->mb_type_pool);
    ff_refstruct_pool_uninit(&h->motion_val_pool);
    ff_refstruct_pool_uninit(&h->ref_index_pool);

#if CONFIG_ERROR_RESILIENCE
    av_freep(&h->er.mb_index2xy);
    av_freep(&h->er.error_status_table);
    av_freep(&h->er.er_temp_buffer);
    av_freep(&h->dc_val_base);
#endif

    for (i = 0; i < h->nb_slice_ctx; i++) {
        H264SliceContext *sl = &h->slice_ctx[i];

        av_freep(&sl->bipred_scratchpad);
        av_freep(&sl->edge_emu_buffer);
        av_freep(&sl->top_borders[0]);
        av_freep(&sl->top_borders[1]);

        sl->bipred_scratchpad_allocated = 0;
        sl->edge_emu_buffer_allocated   = 0;
        sl->top_borders_allocated[0]    = 0;
        sl->top_borders_allocated[1]    = 0;
    }
}

int ff_h264_alloc_tables(H264Context *h)
{
    ERContext *const er = &h->er;
    const int big_mb_num = h->mb_stride * (h->mb_height + 1);
    const int row_mb_num = 2*h->mb_stride*FFMAX(h->nb_slice_ctx, 1);
    const int st_size = big_mb_num + h->mb_stride;
    int x, y;

    if (!FF_ALLOCZ_TYPED_ARRAY(h->intra4x4_pred_mode,     row_mb_num * 8)  ||
        !FF_ALLOCZ_TYPED_ARRAY(h->non_zero_count,         big_mb_num)      ||
        !FF_ALLOCZ_TYPED_ARRAY(h->slice_table_base,       st_size)         ||
        !FF_ALLOCZ_TYPED_ARRAY(h->cbp_table,              big_mb_num)      ||
        !FF_ALLOCZ_TYPED_ARRAY(h->chroma_pred_mode_table, big_mb_num)      ||
        !FF_ALLOCZ_TYPED_ARRAY(h->mvd_table[0],           row_mb_num * 8)  ||
        !FF_ALLOCZ_TYPED_ARRAY(h->mvd_table[1],           row_mb_num * 8)  ||
        !FF_ALLOCZ_TYPED_ARRAY(h->direct_table,           big_mb_num * 4)  ||
        !FF_ALLOCZ_TYPED_ARRAY(h->list_counts,            big_mb_num)      ||
        !FF_ALLOCZ_TYPED_ARRAY(h->mb2b_xy,                big_mb_num)      ||
        !FF_ALLOCZ_TYPED_ARRAY(h->mb2br_xy,               big_mb_num))
        return AVERROR(ENOMEM);
    h->slice_ctx[0].intra4x4_pred_mode = h->intra4x4_pred_mode;
    h->slice_ctx[0].mvd_table[0] = h->mvd_table[0];
    h->slice_ctx[0].mvd_table[1] = h->mvd_table[1];
    memset(h->slice_table_base, -1,
           st_size * sizeof(*h->slice_table_base));
    h->slice_table = h->slice_table_base + h->mb_stride * 2 + 1;
    for (y = 0; y < h->mb_height; y++)
        for (x = 0; x < h->mb_width; x++) {
            const int mb_xy = x + y * h->mb_stride;
            const int b_xy  = 4 * x + 4 * y * h->b_stride;

            h->mb2b_xy[mb_xy]  = b_xy;
            h->mb2br_xy[mb_xy] = 8 * (FMO ? mb_xy : (mb_xy % (2 * h->mb_stride)));
        }

    if (CONFIG_ERROR_RESILIENCE) {
        const int er_size = h->mb_height * h->mb_stride * (4*sizeof(int) + 1);
        int mb_array_size = h->mb_height * h->mb_stride;
        int y_size  = (2 * h->mb_width + 1) * (2 * h->mb_height + 1);
        int yc_size = y_size + 2 * big_mb_num;

        /* init ER */
        er->avctx          = h->avctx;
        er->decode_mb      = h264_er_decode_mb;
        er->opaque         = h;
        er->quarter_sample = 1;

        er->mb_num      = h->mb_num;
        er->mb_width    = h->mb_width;
        er->mb_height   = h->mb_height;
        er->mb_stride   = h->mb_stride;
        er->b8_stride   = h->mb_width * 2 + 1;

        // error resilience code looks cleaner with this
        if (!FF_ALLOCZ_TYPED_ARRAY(er->mb_index2xy,        h->mb_num + 1) ||
            !FF_ALLOCZ_TYPED_ARRAY(er->error_status_table, mb_array_size) ||
            !FF_ALLOCZ_TYPED_ARRAY(er->er_temp_buffer,     er_size)       ||
            !FF_ALLOCZ_TYPED_ARRAY(h->dc_val_base,         yc_size))
            return AVERROR(ENOMEM); // ff_h264_free_tables will clean up for us

        for (y = 0; y < h->mb_height; y++)
            for (x = 0; x < h->mb_width; x++)
                er->mb_index2xy[x + y * h->mb_width] = x + y * h->mb_stride;

        er->mb_index2xy[h->mb_height * h->mb_width] = (h->mb_height - 1) *
                                                      h->mb_stride + h->mb_width;
        er->dc_val[0] = h->dc_val_base + h->mb_width * 2 + 2;
        er->dc_val[1] = h->dc_val_base + y_size + h->mb_stride + 1;
        er->dc_val[2] = er->dc_val[1] + big_mb_num;
        for (int i = 0; i < yc_size; i++)
            h->dc_val_base[i] = 1024;
    }

    return 0;
}

/**
 * Init slice context
 */
void ff_h264_slice_context_init(H264Context *h, H264SliceContext *sl)
{
    sl->ref_cache[0][scan8[5]  + 1] =
    sl->ref_cache[0][scan8[7]  + 1] =
    sl->ref_cache[0][scan8[13] + 1] =
    sl->ref_cache[1][scan8[5]  + 1] =
    sl->ref_cache[1][scan8[7]  + 1] =
    sl->ref_cache[1][scan8[13] + 1] = PART_NOT_AVAILABLE;

    sl->er = &h->er;
}

static int h264_init_pic(H264Picture *pic)
{
    pic->f = av_frame_alloc();
    if (!pic->f)
        return AVERROR(ENOMEM);

    pic->f_grain = av_frame_alloc();
    if (!pic->f_grain)
        return AVERROR(ENOMEM);

    return 0;
}

static int h264_init_context(AVCodecContext *avctx, H264Context *h)
{
    int i, ret;

    h->avctx                 = avctx;
    h->cur_chroma_format_idc = -1;

    h->width_from_caller     = avctx->width;
    h->height_from_caller    = avctx->height;

    h->workaround_bugs       = avctx->workaround_bugs;
    h->flags                 = avctx->flags;
    h->poc.prev_poc_msb      = 1 << 16;
    h->recovery_frame        = -1;
    h->frame_recovered       = 0;
    h->poc.prev_frame_num    = -1;
    h->sei.common.frame_packing.arrangement_cancel_flag = -1;
    h->sei.common.unregistered.x264_build = -1;

    h->next_outputed_poc = INT_MIN;
    for (i = 0; i < FF_ARRAY_ELEMS(h->last_pocs); i++)
        h->last_pocs[i] = INT_MIN;

    ff_h264_sei_uninit(&h->sei);

    if (avctx->active_thread_type & FF_THREAD_FRAME) {
        h->decode_error_flags_pool = ff_refstruct_pool_alloc(sizeof(atomic_int), 0);
        if (!h->decode_error_flags_pool)
            return AVERROR(ENOMEM);
    }

    h->nb_slice_ctx = (avctx->active_thread_type & FF_THREAD_SLICE) ? avctx->thread_count : 1;
    h->slice_ctx = av_calloc(h->nb_slice_ctx, sizeof(*h->slice_ctx));
    if (!h->slice_ctx) {
        h->nb_slice_ctx = 0;
        return AVERROR(ENOMEM);
    }

    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
        if ((ret = h264_init_pic(&h->DPB[i])) < 0)
            return ret;
    }

    if ((ret = h264_init_pic(&h->cur_pic)) < 0)
        return ret;

    if ((ret = h264_init_pic(&h->last_pic_for_ec)) < 0)
        return ret;

    for (i = 0; i < h->nb_slice_ctx; i++)
        h->slice_ctx[i].h264 = h;

    return 0;
}

static void h264_free_pic(H264Context *h, H264Picture *pic)
{
    ff_h264_unref_picture(pic);
    av_frame_free(&pic->f);
    av_frame_free(&pic->f_grain);
}

static av_cold int h264_decode_end(AVCodecContext *avctx)
{
    H264Context *h = avctx->priv_data;
    int i;

    ff_h264_remove_all_refs(h);
    ff_h264_free_tables(h);

    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
        h264_free_pic(h, &h->DPB[i]);
    }
    memset(h->delayed_pic, 0, sizeof(h->delayed_pic));

    h->cur_pic_ptr = NULL;

    ff_refstruct_pool_uninit(&h->decode_error_flags_pool);

    av_freep(&h->slice_ctx);
    h->nb_slice_ctx = 0;

    ff_h264_sei_uninit(&h->sei);
    ff_h264_ps_uninit(&h->ps);

    ff_h2645_packet_uninit(&h->pkt);

    h264_free_pic(h, &h->cur_pic);
    h264_free_pic(h, &h->last_pic_for_ec);

    return 0;
}

static AVOnce h264_vlc_init = AV_ONCE_INIT;

static av_cold int h264_decode_init(AVCodecContext *avctx)
{
    H264Context *h = avctx->priv_data;
    int ret;

    ret = h264_init_context(avctx, h);
    if (ret < 0)
        return ret;

    ret = ff_thread_once(&h264_vlc_init, ff_h264_decode_init_vlc);
    if (ret != 0) {
        av_log(avctx, AV_LOG_ERROR, "pthread_once has failed.");
        return AVERROR_UNKNOWN;
    }

#if FF_API_TICKS_PER_FRAME
FF_DISABLE_DEPRECATION_WARNINGS
    avctx->ticks_per_frame = 2;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    if (!avctx->internal->is_copy) {
        if (avctx->extradata_size > 0 && avctx->extradata) {
            ret = ff_h264_decode_extradata(avctx->extradata, avctx->extradata_size,
                                           &h->ps, &h->is_avc, &h->nal_length_size,
                                           avctx->err_recognition, avctx);
           if (ret < 0) {
               int explode = avctx->err_recognition & AV_EF_EXPLODE;
               av_log(avctx, explode ? AV_LOG_ERROR: AV_LOG_WARNING,
                      "Error decoding the extradata\n");
               if (explode) {
                   return ret;
               }
               ret = 0;
           }
        }
    }

    if (h->ps.sps && h->ps.sps->bitstream_restriction_flag &&
        h->avctx->has_b_frames < h->ps.sps->num_reorder_frames) {
        h->avctx->has_b_frames = h->ps.sps->num_reorder_frames;
    }

    ff_h264_flush_change(h);

    if (h->enable_er < 0 && (avctx->active_thread_type & FF_THREAD_SLICE))
        h->enable_er = 0;

    if (h->enable_er && (avctx->active_thread_type & FF_THREAD_SLICE)) {
        av_log(avctx, AV_LOG_WARNING,
               "Error resilience with slice threads is enabled. It is unsafe and unsupported and may crash. "
               "Use it at your own risk\n");
    }

    return 0;
}

/**
 * instantaneous decoder refresh.
 */
static void idr(H264Context *h)
{
    int i;
    ff_h264_remove_all_refs(h);
    h->poc.prev_frame_num        =
    h->poc.prev_frame_num_offset = 0;
    h->poc.prev_poc_msb          = 1<<16;
    h->poc.prev_poc_lsb          = -1;
    for (i = 0; i < FF_ARRAY_ELEMS(h->last_pocs); i++)
        h->last_pocs[i] = INT_MIN;
}

/* forget old pics after a seek */
void ff_h264_flush_change(H264Context *h)
{
    int i, j;

    h->next_outputed_poc = INT_MIN;
    h->prev_interlaced_frame = 1;
    idr(h);

    h->poc.prev_frame_num = -1;
    if (h->cur_pic_ptr) {
        h->cur_pic_ptr->reference = 0;
        for (j=i=0; h->delayed_pic[i]; i++)
            if (h->delayed_pic[i] != h->cur_pic_ptr)
                h->delayed_pic[j++] = h->delayed_pic[i];
        h->delayed_pic[j] = NULL;
    }
    ff_h264_unref_picture(&h->last_pic_for_ec);

    h->first_field = 0;
    h->recovery_frame = -1;
    h->frame_recovered = 0;
    h->current_slice = 0;
    h->mmco_reset = 1;
}

static void h264_decode_flush(AVCodecContext *avctx)
{
    H264Context *h = avctx->priv_data;
    int i;

    memset(h->delayed_pic, 0, sizeof(h->delayed_pic));

    ff_h264_flush_change(h);
    ff_h264_sei_uninit(&h->sei);

    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++)
        ff_h264_unref_picture(&h->DPB[i]);
    h->cur_pic_ptr = NULL;
    ff_h264_unref_picture(&h->cur_pic);

    h->mb_y = 0;
    h->non_gray = 0;

    ff_h264_free_tables(h);
    h->context_initialized = 0;

    if (FF_HW_HAS_CB(avctx, flush))
        FF_HW_SIMPLE_CALL(avctx, flush);
}

static int get_last_needed_nal(H264Context *h)
{
    int nals_needed = 0;
    int slice_type = 0;
    int picture_intra_only = 1;
    int first_slice = 0;
    int i, ret;

    for (i = 0; i < h->pkt.nb_nals; i++) {
        H2645NAL *nal = &h->pkt.nals[i];
        GetBitContext gb;

        /* packets can sometimes contain multiple PPS/SPS,
         * e.g. two PAFF field pictures in one packet, or a demuxer
         * which splits NALs strangely if so, when frame threading we
         * can't start the next thread until we've read all of them */
        switch (nal->type) {
        case H264_NAL_SPS:
        case H264_NAL_PPS:
            nals_needed = i;
            break;
        case H264_NAL_DPA:
        case H264_NAL_IDR_SLICE:
        case H264_NAL_SLICE:
            ret = init_get_bits8(&gb, nal->data + 1, nal->size - 1);
            if (ret < 0) {
                av_log(h->avctx, AV_LOG_ERROR, "Invalid zero-sized VCL NAL unit\n");
                if (h->avctx->err_recognition & AV_EF_EXPLODE)
                    return ret;

                break;
            }
            if (!get_ue_golomb_long(&gb) ||  // first_mb_in_slice
                !first_slice ||
                first_slice != nal->type)
                nals_needed = i;
            slice_type = get_ue_golomb_31(&gb);
            if (slice_type > 9)
                slice_type = 0;
            if (slice_type > 4)
                slice_type -= 5;

            slice_type = ff_h264_golomb_to_pict_type[slice_type];
            picture_intra_only &= (slice_type & 3) == AV_PICTURE_TYPE_I;
            if (!first_slice)
                first_slice = nal->type;
        }
    }

    h->picture_intra_only = picture_intra_only;

    return nals_needed;
}

static void debug_green_metadata(const H264SEIGreenMetaData *gm, void *logctx)
{
    av_log(logctx, AV_LOG_DEBUG, "Green Metadata Info SEI message\n");
    av_log(logctx, AV_LOG_DEBUG, "  green_metadata_type: %d\n", gm->green_metadata_type);

    if (gm->green_metadata_type == 0) {
        av_log(logctx, AV_LOG_DEBUG, "  green_metadata_period_type: %d\n", gm->period_type);

        if (gm->period_type == 2)
            av_log(logctx, AV_LOG_DEBUG, "  green_metadata_num_seconds: %d\n", gm->num_seconds);
        else if (gm->period_type == 3)
            av_log(logctx, AV_LOG_DEBUG, "  green_metadata_num_pictures: %d\n", gm->num_pictures);

        av_log(logctx, AV_LOG_DEBUG, "  SEI GREEN Complexity Metrics: %f %f %f %f\n",
               (float)gm->percent_non_zero_macroblocks/255,
               (float)gm->percent_intra_coded_macroblocks/255,
               (float)gm->percent_six_tap_filtering/255,
               (float)gm->percent_alpha_point_deblocking_instance/255);

    } else if (gm->green_metadata_type == 1) {
        av_log(logctx, AV_LOG_DEBUG, "  xsd_metric_type: %d\n", gm->xsd_metric_type);

        if (gm->xsd_metric_type == 0)
            av_log(logctx, AV_LOG_DEBUG, "  xsd_metric_value: %f\n",
                   (float)gm->xsd_metric_value/100);
    }
}

static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size)
{
    AVCodecContext *const avctx = h->avctx;
    int nals_needed = 0; ///< number of NALs that need decoding before the next frame thread starts
    int idr_cleared=0;
    int i, ret = 0;

    h->has_slice = 0;
    h->nal_unit_type= 0;

    if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
        h->current_slice = 0;
        if (!h->first_field) {
            h->cur_pic_ptr = NULL;
            ff_h264_sei_uninit(&h->sei);
        }
    }

    if (h->nal_length_size == 4) {
        if (buf_size > 8 && AV_RB32(buf) == 1 && AV_RB32(buf+5) > (unsigned)buf_size) {
            h->is_avc = 0;
        }else if(buf_size > 3 && AV_RB32(buf) > 1 && AV_RB32(buf) <= (unsigned)buf_size)
            h->is_avc = 1;
    }

    ret = ff_h2645_packet_split(&h->pkt, buf, buf_size, avctx, h->nal_length_size,
                                avctx->codec_id, !!h->is_avc * H2645_FLAG_IS_NALFF);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR,
               "Error splitting the input into NAL units.\n");
        return ret;
    }

    if (avctx->active_thread_type & FF_THREAD_FRAME)
        nals_needed = get_last_needed_nal(h);
    if (nals_needed < 0)
        return nals_needed;

    for (i = 0; i < h->pkt.nb_nals; i++) {
        H2645NAL *nal = &h->pkt.nals[i];
        int max_slice_ctx, err;

        if (avctx->skip_frame >= AVDISCARD_NONREF &&
            nal->ref_idc == 0 && nal->type != H264_NAL_SEI)
            continue;

        // FIXME these should stop being context-global variables
        h->nal_ref_idc   = nal->ref_idc;
        h->nal_unit_type = nal->type;

        err = 0;
        switch (nal->type) {
        case H264_NAL_IDR_SLICE:
            if ((nal->data[1] & 0xFC) == 0x98) {
                av_log(h->avctx, AV_LOG_ERROR, "Invalid inter IDR frame\n");
                h->next_outputed_poc = INT_MIN;
                ret = -1;
                goto end;
            }
            if(!idr_cleared) {
                idr(h); // FIXME ensure we don't lose some frames if there is reordering
            }
            idr_cleared = 1;
            h->has_recovery_point = 1;
        case H264_NAL_SLICE:
            h->has_slice = 1;

            if ((err = ff_h264_queue_decode_slice(h, nal))) {
                H264SliceContext *sl = h->slice_ctx + h->nb_slice_ctx_queued;
                sl->ref_count[0] = sl->ref_count[1] = 0;
                break;
            }

            if (h->current_slice == 1) {
                if (avctx->active_thread_type & FF_THREAD_FRAME &&
                    i >= nals_needed && !h->setup_finished && h->cur_pic_ptr) {
                    ff_thread_finish_setup(avctx);
                    h->setup_finished = 1;
                }

                if (h->avctx->hwaccel &&
                    (ret = FF_HW_CALL(h->avctx, start_frame, buf, buf_size)) < 0)
                    goto end;
            }

            max_slice_ctx = avctx->hwaccel ? 1 : h->nb_slice_ctx;
            if (h->nb_slice_ctx_queued == max_slice_ctx) {
                if (h->avctx->hwaccel) {
                    ret = FF_HW_CALL(avctx, decode_slice, nal->raw_data, nal->raw_size);
                    h->nb_slice_ctx_queued = 0;
                } else
                    ret = ff_h264_execute_decode_slices(h);
                if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                    goto end;
            }
            break;
        case H264_NAL_DPA:
        case H264_NAL_DPB:
        case H264_NAL_DPC:
            avpriv_request_sample(avctx, "data partitioning");
            break;
        case H264_NAL_SEI:
            if (h->setup_finished) {
                avpriv_request_sample(avctx, "Late SEI");
                break;
            }
            ret = ff_h264_sei_decode(&h->sei, &nal->gb, &h->ps, avctx);
            h->has_recovery_point = h->has_recovery_point || h->sei.recovery_point.recovery_frame_cnt != -1;
            if (avctx->debug & FF_DEBUG_GREEN_MD)
                debug_green_metadata(&h->sei.green_metadata, h->avctx);
            if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                goto end;
            break;
        case H264_NAL_SPS: {
            GetBitContext tmp_gb = nal->gb;
            if (FF_HW_HAS_CB(avctx, decode_params)) {
                ret = FF_HW_CALL(avctx, decode_params,
                                 nal->type, nal->raw_data, nal->raw_size);
                if (ret < 0)
                    goto end;
            }
            if (ff_h264_decode_seq_parameter_set(&tmp_gb, avctx, &h->ps, 0) >= 0)
                break;
            av_log(h->avctx, AV_LOG_DEBUG,
                   "SPS decoding failure, trying again with the complete NAL\n");
            init_get_bits8(&tmp_gb, nal->raw_data + 1, nal->raw_size - 1);
            if (ff_h264_decode_seq_parameter_set(&tmp_gb, avctx, &h->ps, 0) >= 0)
                break;
            ff_h264_decode_seq_parameter_set(&nal->gb, avctx, &h->ps, 1);
            break;
        }
        case H264_NAL_PPS:
            if (FF_HW_HAS_CB(avctx, decode_params)) {
                ret = FF_HW_CALL(avctx, decode_params,
                                 nal->type, nal->raw_data, nal->raw_size);
                if (ret < 0)
                    goto end;
            }
            ret = ff_h264_decode_picture_parameter_set(&nal->gb, avctx, &h->ps,
                                                       nal->size_bits);
            if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                goto end;
            break;
        case H264_NAL_AUD:
        case H264_NAL_END_SEQUENCE:
        case H264_NAL_END_STREAM:
        case H264_NAL_FILLER_DATA:
        case H264_NAL_SPS_EXT:
        case H264_NAL_AUXILIARY_SLICE:
            break;
        default:
            av_log(avctx, AV_LOG_DEBUG, "Unknown NAL code: %d (%d bits)\n",
                   nal->type, nal->size_bits);
        }

        if (err < 0) {
            av_log(h->avctx, AV_LOG_ERROR, "decode_slice_header error\n");
        }
    }

    ret = ff_h264_execute_decode_slices(h);
    if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
        goto end;

    // set decode_error_flags to allow users to detect concealed decoding errors
    if ((ret < 0 || h->er.error_occurred) && h->cur_pic_ptr) {
        if (h->cur_pic_ptr->decode_error_flags) {
            /* Frame-threading in use */
            atomic_int *decode_error = h->cur_pic_ptr->decode_error_flags;
            /* Using atomics here is not supposed to provide syncronisation;
             * they are merely used to allow to set decode_error from both
             * decoding threads in case of coded slices. */
            atomic_fetch_or_explicit(decode_error, FF_DECODE_ERROR_DECODE_SLICES,
                                     memory_order_relaxed);
        } else
            h->cur_pic_ptr->f->decode_error_flags |= FF_DECODE_ERROR_DECODE_SLICES;
    }

    ret = 0;
end:

#if CONFIG_ERROR_RESILIENCE
    /*
     * FIXME: Error handling code does not seem to support interlaced
     * when slices span multiple rows
     * The ff_er_add_slice calls don't work right for bottom
     * fields; they cause massive erroneous error concealing
     * Error marking covers both fields (top and bottom).
     * This causes a mismatched s->error_count
     * and a bad error table. Further, the error count goes to
     * INT_MAX when called for bottom field, because mb_y is
     * past end by one (callers fault) and resync_mb_y != 0
     * causes problems for the first MB line, too.
     */
    if (!FIELD_PICTURE(h) && h->current_slice && h->enable_er) {

        H264SliceContext *sl = h->slice_ctx;
        int use_last_pic = h->last_pic_for_ec.f->buf[0] && !sl->ref_count[0];
        int decode_error_flags = 0;

        ff_h264_set_erpic(&h->er.cur_pic, h->cur_pic_ptr);

        if (use_last_pic) {
            ff_h264_set_erpic(&h->er.last_pic, &h->last_pic_for_ec);
            sl->ref_list[0][0].parent = &h->last_pic_for_ec;
            memcpy(sl->ref_list[0][0].data, h->last_pic_for_ec.f->data, sizeof(sl->ref_list[0][0].data));
            memcpy(sl->ref_list[0][0].linesize, h->last_pic_for_ec.f->linesize, sizeof(sl->ref_list[0][0].linesize));
            sl->ref_list[0][0].reference = h->last_pic_for_ec.reference;
        } else if (sl->ref_count[0]) {
            ff_h264_set_erpic(&h->er.last_pic, sl->ref_list[0][0].parent);
        } else
            ff_h264_set_erpic(&h->er.last_pic, NULL);

        if (sl->ref_count[1])
            ff_h264_set_erpic(&h->er.next_pic, sl->ref_list[1][0].parent);

        ff_er_frame_end(&h->er, &decode_error_flags);
        if (decode_error_flags) {
            if (h->cur_pic_ptr->decode_error_flags) {
                atomic_int *decode_error = h->cur_pic_ptr->decode_error_flags;
                atomic_fetch_or_explicit(decode_error, decode_error_flags,
                                         memory_order_relaxed);
            } else
                h->cur_pic_ptr->f->decode_error_flags |= decode_error_flags;
        }
        if (use_last_pic)
            memset(&sl->ref_list[0][0], 0, sizeof(sl->ref_list[0][0]));
    }
#endif /* CONFIG_ERROR_RESILIENCE */
    /* clean up */
    if (h->cur_pic_ptr && !h->droppable && h->has_slice) {
        ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                  h->picture_structure == PICT_BOTTOM_FIELD);
    }

    return (ret < 0) ? ret : buf_size;
}

/**
 * Return the number of bytes consumed for building the current frame.
 */
static int get_consumed_bytes(int pos, int buf_size)
{
    if (pos == 0)
        pos = 1;        // avoid infinite loops (I doubt that is needed but...)
    if (pos + 10 > buf_size)
        pos = buf_size; // oops ;)

    return pos;
}

static int h264_export_enc_params(AVFrame *f, const H264Picture *p)
{
    AVVideoEncParams *par;
    unsigned int nb_mb = p->mb_height * p->mb_width;
    unsigned int x, y;

    par = av_video_enc_params_create_side_data(f, AV_VIDEO_ENC_PARAMS_H264, nb_mb);
    if (!par)
        return AVERROR(ENOMEM);

    par->qp = p->pps->init_qp;

    par->delta_qp[1][0] = p->pps->chroma_qp_index_offset[0];
    par->delta_qp[1][1] = p->pps->chroma_qp_index_offset[0];
    par->delta_qp[2][0] = p->pps->chroma_qp_index_offset[1];
    par->delta_qp[2][1] = p->pps->chroma_qp_index_offset[1];

    for (y = 0; y < p->mb_height; y++)
        for (x = 0; x < p->mb_width; x++) {
            const unsigned int block_idx = y * p->mb_width + x;
            const unsigned int     mb_xy = y * p->mb_stride + x;
            AVVideoBlockParams *b = av_video_enc_params_block(par, block_idx);

            b->src_x = x * 16;
            b->src_y = y * 16;
            b->w     = 16;
            b->h     = 16;

            b->delta_qp = p->qscale_table[mb_xy] - par->qp;
        }

    return 0;
}

static int output_frame(H264Context *h, AVFrame *dst, H264Picture *srcp)
{
    int ret;

    ret = av_frame_ref(dst, srcp->needs_fg ? srcp->f_grain : srcp->f);
    if (ret < 0)
        return ret;

    if (srcp->needs_fg && (ret = av_frame_copy_props(dst, srcp->f)) < 0)
        return ret;

    if (srcp->decode_error_flags) {
        atomic_int *decode_error = srcp->decode_error_flags;
        /* The following is not supposed to provide synchronisation at all:
         * given that srcp has already finished decoding, decode_error
         * has already been set to its final value. */
        dst->decode_error_flags |= atomic_load_explicit(decode_error, memory_order_relaxed);
    }

    av_dict_set(&dst->metadata, "stereo_mode", ff_h264_sei_stereo_mode(&h->sei.common.frame_packing), 0);

    if (srcp->sei_recovery_frame_cnt == 0)
        dst->flags |= AV_FRAME_FLAG_KEY;

    if (h->avctx->export_side_data & AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS) {
        ret = h264_export_enc_params(dst, srcp);
        if (ret < 0)
            goto fail;
    }

    if (!(h->avctx->export_side_data & AV_CODEC_EXPORT_DATA_FILM_GRAIN))
        av_frame_remove_side_data(dst, AV_FRAME_DATA_FILM_GRAIN_PARAMS);

    return 0;
fail:
    av_frame_unref(dst);
    return ret;
}

static int is_avcc_extradata(const uint8_t *buf, int buf_size)
{
    int cnt= buf[5]&0x1f;
    const uint8_t *p= buf+6;
    if (!cnt)
        return 0;
    while(cnt--){
        int nalsize= AV_RB16(p) + 2;
        if(nalsize > buf_size - (p-buf) || (p[2] & 0x9F) != 7)
            return 0;
        p += nalsize;
    }
    cnt = *(p++);
    if(!cnt)
        return 0;
    while(cnt--){
        int nalsize= AV_RB16(p) + 2;
        if(nalsize > buf_size - (p-buf) || (p[2] & 0x9F) != 8)
            return 0;
        p += nalsize;
    }
    return 1;
}

static int finalize_frame(H264Context *h, AVFrame *dst, H264Picture *out, int *got_frame)
{
    int ret;

    if (((h->avctx->flags & AV_CODEC_FLAG_OUTPUT_CORRUPT) ||
         (h->avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL) ||
         out->recovered)) {

        if (h->skip_gray > 0 &&
            h->non_gray && out->gray &&
            !(h->avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL)
        )
            return 0;

        if (!h->avctx->hwaccel &&
            (out->field_poc[0] == INT_MAX ||
             out->field_poc[1] == INT_MAX)
           ) {
            int p;
            AVFrame *f = out->f;
            int field = out->field_poc[0] == INT_MAX;
            uint8_t *dst_data[4];
            int linesizes[4];
            const uint8_t *src_data[4];

            av_log(h->avctx, AV_LOG_DEBUG, "Duplicating field %d to fill missing\n", field);

            for (p = 0; p<4; p++) {
                dst_data[p] = f->data[p] + (field^1)*f->linesize[p];
                src_data[p] = f->data[p] +  field   *f->linesize[p];
                linesizes[p] = 2*f->linesize[p];
            }

            av_image_copy(dst_data, linesizes, src_data, linesizes,
                          f->format, f->width, f->height>>1);
        }

        ret = output_frame(h, dst, out);
        if (ret < 0)
            return ret;

        *got_frame = 1;

        if (CONFIG_MPEGVIDEODEC) {
            ff_print_debug_info2(h->avctx, dst,
                                 out->mb_type,
                                 out->qscale_table,
                                 out->motion_val,
                                 out->mb_width, out->mb_height, out->mb_stride, 1);
        }
    }

    return 0;
}

static int send_next_delayed_frame(H264Context *h, AVFrame *dst_frame,
                                   int *got_frame, int buf_index)
{
    int ret, i, out_idx;
    H264Picture *out;

    h->cur_pic_ptr = NULL;
    h->first_field = 0;

    while (h->delayed_pic[0]) {
        out = h->delayed_pic[0];
        out_idx = 0;
        for (i = 1;
             h->delayed_pic[i] &&
             !(h->delayed_pic[i]->f->flags & AV_FRAME_FLAG_KEY) &&
             !h->delayed_pic[i]->mmco_reset;
             i++)
            if (h->delayed_pic[i]->poc < out->poc) {
                out     = h->delayed_pic[i];
                out_idx = i;
            }

        for (i = out_idx; h->delayed_pic[i]; i++)
            h->delayed_pic[i] = h->delayed_pic[i + 1];

        if (out) {
            h->frame_recovered |= out->recovered;
            out->recovered |= h->frame_recovered & FRAME_RECOVERED_SEI;

            out->reference &= ~DELAYED_PIC_REF;
            ret = finalize_frame(h, dst_frame, out, got_frame);
            if (ret < 0)
                return ret;
            if (*got_frame)
                break;
        }
    }

    return buf_index;
}

static int h264_decode_frame(AVCodecContext *avctx, AVFrame *pict,
                             int *got_frame, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;
    H264Context *h     = avctx->priv_data;
    int buf_index;
    int ret;

    h->flags = avctx->flags;
    h->setup_finished = 0;
    h->nb_slice_ctx_queued = 0;

    ff_h264_unref_picture(&h->last_pic_for_ec);

    /* end of stream, output what is still in the buffers */
    if (buf_size == 0)
        return send_next_delayed_frame(h, pict, got_frame, 0);

    if (av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA, NULL)) {
        size_t side_size;
        uint8_t *side = av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA, &side_size);
        ff_h264_decode_extradata(side, side_size,
                                 &h->ps, &h->is_avc, &h->nal_length_size,
                                 avctx->err_recognition, avctx);
    }
    if (h->is_avc && buf_size >= 9 && buf[0]==1 && buf[2]==0 && (buf[4]&0xFC)==0xFC) {
        if (is_avcc_extradata(buf, buf_size))
            return ff_h264_decode_extradata(buf, buf_size,
                                            &h->ps, &h->is_avc, &h->nal_length_size,
                                            avctx->err_recognition, avctx);
    }

    buf_index = decode_nal_units(h, buf, buf_size);
    if (buf_index < 0)
        return AVERROR_INVALIDDATA;

    if (!h->cur_pic_ptr && h->nal_unit_type == H264_NAL_END_SEQUENCE) {
        av_assert0(buf_index <= buf_size);
        return send_next_delayed_frame(h, pict, got_frame, buf_index);
    }

    if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) && (!h->cur_pic_ptr || !h->has_slice)) {
        if (avctx->skip_frame >= AVDISCARD_NONREF ||
            buf_size >= 4 && !memcmp("Q264", buf, 4))
            return buf_size;
        av_log(avctx, AV_LOG_ERROR, "no frame!\n");
        return AVERROR_INVALIDDATA;
    }

    if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) ||
        (h->mb_y >= h->mb_height && h->mb_height)) {
        if ((ret = ff_h264_field_end(h, &h->slice_ctx[0], 0)) < 0)
            return ret;

        /* Wait for second field. */
        if (h->next_output_pic) {
            ret = finalize_frame(h, pict, h->next_output_pic, got_frame);
            if (ret < 0)
                return ret;
        }
    }

    av_assert0(pict->buf[0] || !*got_frame);

    ff_h264_unref_picture(&h->last_pic_for_ec);

    return get_consumed_bytes(buf_index, buf_size);
}

#define OFFSET(x) offsetof(H264Context, x)
#define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
#define VDX VD | AV_OPT_FLAG_EXPORT
static const AVOption h264_options[] = {
    { "is_avc", "is avc", OFFSET(is_avc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, VDX },
    { "nal_length_size", "nal_length_size", OFFSET(nal_length_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 4, VDX },
    { "enable_er", "Enable error resilience on damaged frames (unsafe)", OFFSET(enable_er), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, VD },
    { "x264_build", "Assume this x264 version if no x264 version found in any SEI", OFFSET(x264_build), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, VD },
    { "skip_gray", "Do not return gray gap frames", OFFSET(skip_gray), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, VD },
    { "noref_gray", "Avoid using gray gap frames as references", OFFSET(noref_gray), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, VD },
    { NULL },
};

static const AVClass h264_class = {
    .class_name = "H264 Decoder",
    .item_name  = av_default_item_name,
    .option     = h264_options,
    .version    = LIBAVUTIL_VERSION_INT,
};

const FFCodec ff_h264_decoder = {
    .p.name                = "h264",
    CODEC_LONG_NAME("H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10"),
    .p.type                = AVMEDIA_TYPE_VIDEO,
    .p.id                  = AV_CODEC_ID_H264,
    .priv_data_size        = sizeof(H264Context),
    .init                  = h264_decode_init,
    .close                 = h264_decode_end,
    FF_CODEC_DECODE_CB(h264_decode_frame),
    .p.capabilities        = AV_CODEC_CAP_DR1 |
                             AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS |
                             AV_CODEC_CAP_FRAME_THREADS,
    .hw_configs            = (const AVCodecHWConfigInternal *const []) {
#if CONFIG_H264_DXVA2_HWACCEL
                               HWACCEL_DXVA2(h264),
#endif
#if CONFIG_H264_D3D11VA_HWACCEL
                               HWACCEL_D3D11VA(h264),
#endif
#if CONFIG_H264_D3D11VA2_HWACCEL
                               HWACCEL_D3D11VA2(h264),
#endif
#if CONFIG_H264_D3D12VA_HWACCEL
                               HWACCEL_D3D12VA(h264),
#endif
#if CONFIG_H264_NVDEC_HWACCEL
                               HWACCEL_NVDEC(h264),
#endif
#if CONFIG_H264_VAAPI_HWACCEL
                               HWACCEL_VAAPI(h264),
#endif
#if CONFIG_H264_VDPAU_HWACCEL
                               HWACCEL_VDPAU(h264),
#endif
#if CONFIG_H264_VIDEOTOOLBOX_HWACCEL
                               HWACCEL_VIDEOTOOLBOX(h264),
#endif
#if CONFIG_H264_VULKAN_HWACCEL
                               HWACCEL_VULKAN(h264),
#endif
                               NULL
                           },
    .caps_internal         = FF_CODEC_CAP_EXPORTS_CROPPING |
                             FF_CODEC_CAP_INIT_CLEANUP,
    .flush                 = h264_decode_flush,
    UPDATE_THREAD_CONTEXT(ff_h264_update_thread_context),
    UPDATE_THREAD_CONTEXT_FOR_USER(ff_h264_update_thread_context_for_user),
    .p.profiles            = NULL_IF_CONFIG_SMALL(ff_h264_profiles),
    .p.priv_class          = &h264_class,
};