aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/avisynth.c
blob: 625bdf7e3a6f9329810c7d4d659db28b61211a22 (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
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
/*
 * AviSynth(+) support
 * Copyright (c) 2012 AvxSynth Team
 *
 * 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
 */

#include "libavutil/attributes.h"
#include "libavutil/internal.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/thread.h"

#include "avformat.h"
#include "demux.h"
#include "internal.h"
#include "config.h"

/* Enable function pointer definitions for runtime loading. */
#define AVSC_NO_DECLSPEC

/* Platform-specific directives. */
#ifdef _WIN32
  #include "compat/w32dlfcn.h"
  #include "libavutil/wchar_filename.h"
  #undef EXTERN_C
  #define AVISYNTH_LIB "avisynth"
#else
  #include <dlfcn.h>
  #define AVISYNTH_NAME "libavisynth"
  #define AVISYNTH_LIB AVISYNTH_NAME SLIBSUF
#endif

/* Endianness guards for audio */
#if HAVE_BIGENDIAN
    #define PCM(format) (AV_CODEC_ID_PCM_ ## format ## BE)
#else
    #define PCM(format) (AV_CODEC_ID_PCM_ ## format ## LE)
#endif

#include <avisynth/avisynth_c.h>

typedef struct AviSynthLibrary {
    void *library;
#define AVSC_DECLARE_FUNC(name) name ## _func name
    AVSC_DECLARE_FUNC(avs_bit_blt);
    AVSC_DECLARE_FUNC(avs_clip_get_error);
    AVSC_DECLARE_FUNC(avs_check_version);
    AVSC_DECLARE_FUNC(avs_create_script_environment);
    AVSC_DECLARE_FUNC(avs_delete_script_environment);
    AVSC_DECLARE_FUNC(avs_get_audio);
    AVSC_DECLARE_FUNC(avs_get_channel_mask);
    AVSC_DECLARE_FUNC(avs_get_error);
    AVSC_DECLARE_FUNC(avs_get_frame);
    AVSC_DECLARE_FUNC(avs_get_version);
    AVSC_DECLARE_FUNC(avs_get_video_info);
    AVSC_DECLARE_FUNC(avs_invoke);
    AVSC_DECLARE_FUNC(avs_is_color_space);
    AVSC_DECLARE_FUNC(avs_release_clip);
    AVSC_DECLARE_FUNC(avs_release_value);
    AVSC_DECLARE_FUNC(avs_release_video_frame);
    AVSC_DECLARE_FUNC(avs_take_clip);
    AVSC_DECLARE_FUNC(avs_bits_per_pixel);
    AVSC_DECLARE_FUNC(avs_get_height_p);
    AVSC_DECLARE_FUNC(avs_get_pitch_p);
    AVSC_DECLARE_FUNC(avs_get_read_ptr_p);
    AVSC_DECLARE_FUNC(avs_get_row_size_p);
    AVSC_DECLARE_FUNC(avs_is_planar_rgb);
    AVSC_DECLARE_FUNC(avs_is_planar_rgba);
    AVSC_DECLARE_FUNC(avs_get_frame_props_ro);
    AVSC_DECLARE_FUNC(avs_prop_get_int);
    AVSC_DECLARE_FUNC(avs_prop_get_type);
    AVSC_DECLARE_FUNC(avs_get_env_property);
#undef AVSC_DECLARE_FUNC
} AviSynthLibrary;

typedef enum AviSynthFlags {
    AVISYNTH_FRAMEPROP_FIELD_ORDER = (1 << 0),
    AVISYNTH_FRAMEPROP_RANGE = (1 << 1),
    AVISYNTH_FRAMEPROP_PRIMARIES = (1 << 2),
    AVISYNTH_FRAMEPROP_TRANSFER = (1 << 3),
    AVISYNTH_FRAMEPROP_MATRIX = (1 << 4),
    AVISYNTH_FRAMEPROP_CHROMA_LOCATION = (1 << 5),
    AVISYNTH_FRAMEPROP_SAR = (1 << 6),
} AviSynthFlags;

typedef struct AviSynthContext {
    const AVClass *class;
    AVS_ScriptEnvironment *env;
    AVS_Clip *clip;
    const AVS_VideoInfo *vi;

    /* avisynth_read_packet_video() iterates over this. */
    int n_planes;
    const int *planes;

    int curr_stream;
    int curr_frame;
    int64_t curr_sample;

    int error;

    uint32_t flags;

    /* Linked list pointers. */
    struct AviSynthContext *next;
} AviSynthContext;

static const int avs_planes_packed[1] = { 0 };
static const int avs_planes_grey[1]   = { AVS_PLANAR_Y };
static const int avs_planes_yuv[3]    = { AVS_PLANAR_Y, AVS_PLANAR_U,
                                          AVS_PLANAR_V };
static const int avs_planes_rgb[3]    = { AVS_PLANAR_G, AVS_PLANAR_B,
                                          AVS_PLANAR_R };
static const int avs_planes_yuva[4]   = { AVS_PLANAR_Y, AVS_PLANAR_U,
                                          AVS_PLANAR_V, AVS_PLANAR_A };
static const int avs_planes_rgba[4]   = { AVS_PLANAR_G, AVS_PLANAR_B,
                                          AVS_PLANAR_R, AVS_PLANAR_A };

static AVMutex avisynth_mutex = AV_MUTEX_INITIALIZER;

/* A conflict between C++ global objects, atexit, and dynamic loading requires
 * us to register our own atexit handler to prevent double freeing. */
static AviSynthLibrary avs_library;
static int avs_atexit_called        = 0;

/* Linked list of AviSynthContexts. An atexit handler destroys this list. */
static AviSynthContext *avs_ctx_list = NULL;

static av_cold void avisynth_atexit_handler(void);

static av_cold int avisynth_load_library(void)
{
    avs_library.library = dlopen(AVISYNTH_LIB, RTLD_NOW | RTLD_LOCAL);
    if (!avs_library.library)
        return AVERROR_UNKNOWN;

#define LOAD_AVS_FUNC(name, continue_on_fail)                          \
        avs_library.name = (name ## _func)                             \
                           dlsym(avs_library.library, #name);          \
        if (!continue_on_fail && !avs_library.name)                    \
            goto fail;

    LOAD_AVS_FUNC(avs_bit_blt, 0);
    LOAD_AVS_FUNC(avs_clip_get_error, 0);
    LOAD_AVS_FUNC(avs_check_version, 0);
    LOAD_AVS_FUNC(avs_create_script_environment, 0);
    LOAD_AVS_FUNC(avs_delete_script_environment, 0);
    LOAD_AVS_FUNC(avs_get_audio, 0);
    LOAD_AVS_FUNC(avs_get_channel_mask, 1);
    LOAD_AVS_FUNC(avs_get_error, 1); // New to AviSynth 2.6
    LOAD_AVS_FUNC(avs_get_frame, 0);
    LOAD_AVS_FUNC(avs_get_version, 0);
    LOAD_AVS_FUNC(avs_get_video_info, 0);
    LOAD_AVS_FUNC(avs_invoke, 0);
    LOAD_AVS_FUNC(avs_is_color_space, 1);
    LOAD_AVS_FUNC(avs_release_clip, 0);
    LOAD_AVS_FUNC(avs_release_value, 0);
    LOAD_AVS_FUNC(avs_release_video_frame, 0);
    LOAD_AVS_FUNC(avs_take_clip, 0);
    LOAD_AVS_FUNC(avs_bits_per_pixel, 1);
    LOAD_AVS_FUNC(avs_get_height_p, 1);
    LOAD_AVS_FUNC(avs_get_pitch_p, 1);
    LOAD_AVS_FUNC(avs_get_read_ptr_p, 1);
    LOAD_AVS_FUNC(avs_get_row_size_p, 1);
    LOAD_AVS_FUNC(avs_is_planar_rgb, 1);
    LOAD_AVS_FUNC(avs_is_planar_rgba, 1);
    LOAD_AVS_FUNC(avs_get_frame_props_ro, 1);
    LOAD_AVS_FUNC(avs_prop_get_int, 1);
    LOAD_AVS_FUNC(avs_prop_get_type, 1);
    LOAD_AVS_FUNC(avs_get_env_property, 1);
#undef LOAD_AVS_FUNC

    atexit(avisynth_atexit_handler);
    return 0;

fail:
    dlclose(avs_library.library);
    return AVERROR_UNKNOWN;
}

/* Note that avisynth_context_create and avisynth_context_destroy
 * do not allocate or free the actual context! That is taken care of
 * by libavformat. */
static av_cold int avisynth_context_create(AVFormatContext *s)
{
    AviSynthContext *avs = s->priv_data;
    int ret;

    if (!avs_library.library)
        if (ret = avisynth_load_library())
            return ret;

    avs->env = avs_library.avs_create_script_environment(3);
    if (avs_library.avs_get_error) {
        const char *error = avs_library.avs_get_error(avs->env);
        if (error) {
            av_log(s, AV_LOG_ERROR, "%s\n", error);
            return AVERROR_UNKNOWN;
        }
    }

    if (!avs_ctx_list) {
        avs_ctx_list = avs;
    } else {
        avs->next    = avs_ctx_list;
        avs_ctx_list = avs;
    }

    return 0;
}

static av_cold void avisynth_context_destroy(AviSynthContext *avs)
{
    if (avs_atexit_called)
        return;

    if (avs == avs_ctx_list) {
        avs_ctx_list = avs->next;
    } else {
        AviSynthContext *prev = avs_ctx_list;
        while (prev->next != avs)
            prev = prev->next;
        prev->next = avs->next;
    }

    if (avs->clip) {
        avs_library.avs_release_clip(avs->clip);
        avs->clip = NULL;
    }
    if (avs->env) {
        avs_library.avs_delete_script_environment(avs->env);
        avs->env = NULL;
    }
}

static av_cold void avisynth_atexit_handler(void)
{
    AviSynthContext *avs = avs_ctx_list;

    while (avs) {
        AviSynthContext *next = avs->next;
        avisynth_context_destroy(avs);
        avs = next;
    }
    dlclose(avs_library.library);

    avs_atexit_called = 1;
}

/* Create AVStream from audio and video data. */
static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st)
{
    AviSynthContext *avs = s->priv_data;
    const AVS_Map *avsmap;
    AVS_VideoFrame *frame;
    int error;
    int planar = 0; // 0: packed, 1: YUV, 2: Y8, 3: Planar RGB, 4: YUVA, 5: Planar RGBA
    int sar_num = 1;
    int sar_den = 1;

    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codecpar->codec_id   = AV_CODEC_ID_RAWVIDEO;
    st->codecpar->width      = avs->vi->width;
    st->codecpar->height     = avs->vi->height;

    st->avg_frame_rate    = (AVRational) { avs->vi->fps_numerator,
                                           avs->vi->fps_denominator };
    st->start_time        = 0;
    st->duration          = avs->vi->num_frames;
    st->nb_frames         = avs->vi->num_frames;
    avpriv_set_pts_info(st, 32, avs->vi->fps_denominator, avs->vi->fps_numerator);


    switch (avs->vi->pixel_type) {
    /* 10~16-bit YUV pix_fmts (AviSynth+) */
    case AVS_CS_YUV444P10:
        st->codecpar->format = AV_PIX_FMT_YUV444P10;
        planar               = 1;
        break;
    case AVS_CS_YUV422P10:
        st->codecpar->format = AV_PIX_FMT_YUV422P10;
        planar               = 1;
        break;
    case AVS_CS_YUV420P10:
        st->codecpar->format = AV_PIX_FMT_YUV420P10;
        planar               = 1;
        break;
    case AVS_CS_YUV444P12:
        st->codecpar->format = AV_PIX_FMT_YUV444P12;
        planar               = 1;
        break;
    case AVS_CS_YUV422P12:
        st->codecpar->format = AV_PIX_FMT_YUV422P12;
        planar               = 1;
        break;
    case AVS_CS_YUV420P12:
        st->codecpar->format = AV_PIX_FMT_YUV420P12;
        planar               = 1;
        break;
    case AVS_CS_YUV444P14:
        st->codecpar->format = AV_PIX_FMT_YUV444P14;
        planar               = 1;
        break;
    case AVS_CS_YUV422P14:
        st->codecpar->format = AV_PIX_FMT_YUV422P14;
        planar               = 1;
        break;
    case AVS_CS_YUV420P14:
        st->codecpar->format = AV_PIX_FMT_YUV420P14;
        planar               = 1;
        break;
    case AVS_CS_YUV444P16:
        st->codecpar->format = AV_PIX_FMT_YUV444P16;
        planar               = 1;
        break;
    case AVS_CS_YUV422P16:
        st->codecpar->format = AV_PIX_FMT_YUV422P16;
        planar               = 1;
        break;
    case AVS_CS_YUV420P16:
        st->codecpar->format = AV_PIX_FMT_YUV420P16;
        planar               = 1;
        break;
    /* 8~16-bit YUV pix_fmts with Alpha (AviSynth+) */
    case AVS_CS_YUVA444:
        st->codecpar->format = AV_PIX_FMT_YUVA444P;
        planar               = 4;
        break;
    case AVS_CS_YUVA422:
        st->codecpar->format = AV_PIX_FMT_YUVA422P;
        planar               = 4;
        break;
    case AVS_CS_YUVA420:
        st->codecpar->format = AV_PIX_FMT_YUVA420P;
        planar               = 4;
        break;
    case AVS_CS_YUVA444P10:
        st->codecpar->format = AV_PIX_FMT_YUVA444P10;
        planar               = 4;
        break;
    case AVS_CS_YUVA422P10:
        st->codecpar->format = AV_PIX_FMT_YUVA422P10;
        planar               = 4;
        break;
    case AVS_CS_YUVA420P10:
        st->codecpar->format = AV_PIX_FMT_YUVA420P10;
        planar               = 4;
        break;
    case AVS_CS_YUVA422P12:
        st->codecpar->format = AV_PIX_FMT_YUVA422P12;
        planar               = 4;
        break;
    case AVS_CS_YUVA444P16:
        st->codecpar->format = AV_PIX_FMT_YUVA444P16;
        planar               = 4;
        break;
    case AVS_CS_YUVA422P16:
        st->codecpar->format = AV_PIX_FMT_YUVA422P16;
        planar               = 4;
        break;
    case AVS_CS_YUVA420P16:
        st->codecpar->format = AV_PIX_FMT_YUVA420P16;
        planar               = 4;
        break;
    /* Planar RGB pix_fmts (AviSynth+) */
    case AVS_CS_RGBP:
        st->codecpar->format = AV_PIX_FMT_GBRP;
        planar               = 3;
        break;
    case AVS_CS_RGBP10:
        st->codecpar->format = AV_PIX_FMT_GBRP10;
        planar               = 3;
        break;
    case AVS_CS_RGBP12:
        st->codecpar->format = AV_PIX_FMT_GBRP12;
        planar               = 3;
        break;
    case AVS_CS_RGBP14:
        st->codecpar->format = AV_PIX_FMT_GBRP14;
        planar               = 3;
        break;
    case AVS_CS_RGBP16:
        st->codecpar->format = AV_PIX_FMT_GBRP16;
        planar               = 3;
        break;
    /* Single precision floating point Planar RGB (AviSynth+) */
    case AVS_CS_RGBPS:
        st->codecpar->format = AV_PIX_FMT_GBRPF32;
        planar               = 3;
        break;
    /* Planar RGB pix_fmts with Alpha (AviSynth+) */
    case AVS_CS_RGBAP:
        st->codecpar->format = AV_PIX_FMT_GBRAP;
        planar               = 5;
        break;
    case AVS_CS_RGBAP10:
        st->codecpar->format = AV_PIX_FMT_GBRAP10;
        planar               = 5;
        break;
    case AVS_CS_RGBAP12:
        st->codecpar->format = AV_PIX_FMT_GBRAP12;
        planar               = 5;
        break;
    case AVS_CS_RGBAP16:
        st->codecpar->format = AV_PIX_FMT_GBRAP16;
        planar               = 5;
        break;
    /* Single precision floating point Planar RGB with Alpha (AviSynth+) */
    case AVS_CS_RGBAPS:
        st->codecpar->format = AV_PIX_FMT_GBRAPF32;
        planar               = 5;
        break;
    /* 10~16-bit gray pix_fmts (AviSynth+) */
    case AVS_CS_Y10:
        st->codecpar->format = AV_PIX_FMT_GRAY10;
        planar               = 2;
        break;
    case AVS_CS_Y12:
        st->codecpar->format = AV_PIX_FMT_GRAY12;
        planar               = 2;
        break;
    case AVS_CS_Y14:
        st->codecpar->format = AV_PIX_FMT_GRAY14;
        planar               = 2;
        break;
    case AVS_CS_Y16:
        st->codecpar->format = AV_PIX_FMT_GRAY16;
        planar               = 2;
        break;
    /* Single precision floating point gray (AviSynth+) */
    case AVS_CS_Y32:
        st->codecpar->format = AV_PIX_FMT_GRAYF32;
        planar               = 2;
        break;
    /* pix_fmts added in AviSynth 2.6 */
    case AVS_CS_YV24:
        st->codecpar->format = AV_PIX_FMT_YUV444P;
        planar               = 1;
        break;
    case AVS_CS_YV16:
        st->codecpar->format = AV_PIX_FMT_YUV422P;
        planar               = 1;
        break;
    case AVS_CS_YV411:
        st->codecpar->format = AV_PIX_FMT_YUV411P;
        planar               = 1;
        break;
    case AVS_CS_Y8:
        st->codecpar->format = AV_PIX_FMT_GRAY8;
        planar               = 2;
        break;
    /* 16-bit packed RGB pix_fmts (AviSynth+) */
    case AVS_CS_BGR48:
        st->codecpar->format = AV_PIX_FMT_BGR48;
        break;
    case AVS_CS_BGR64:
        st->codecpar->format = AV_PIX_FMT_BGRA64;
        break;
    /* AviSynth 2.5 pix_fmts */
    case AVS_CS_BGR24:
        st->codecpar->format = AV_PIX_FMT_BGR24;
        break;
    case AVS_CS_BGR32:
        st->codecpar->format = AV_PIX_FMT_RGB32;
        break;
    case AVS_CS_YUY2:
        st->codecpar->format = AV_PIX_FMT_YUYV422;
        break;
    case AVS_CS_YV12:
        st->codecpar->format = AV_PIX_FMT_YUV420P;
        planar               = 1;
        break;
    case AVS_CS_I420: // Is this even used anywhere?
        st->codecpar->format = AV_PIX_FMT_YUV420P;
        planar               = 1;
        break;
    default:
        av_log(s, AV_LOG_ERROR,
               "unknown AviSynth colorspace %d\n", avs->vi->pixel_type);
        avs->error = 1;
        return AVERROR_UNKNOWN;
    }

    switch (planar) {
    case 5: // Planar RGB + Alpha
        avs->n_planes = 4;
        avs->planes   = avs_planes_rgba;
        break;
    case 4: // YUV + Alpha
        avs->n_planes = 4;
        avs->planes   = avs_planes_yuva;
        break;
    case 3: // Planar RGB
        avs->n_planes = 3;
        avs->planes   = avs_planes_rgb;
        break;
    case 2: // Y8
        avs->n_planes = 1;
        avs->planes   = avs_planes_grey;
        break;
    case 1: // YUV
        avs->n_planes = 3;
        avs->planes   = avs_planes_yuv;
        break;
    default:
        avs->n_planes = 1;
        avs->planes   = avs_planes_packed;
    }

    /* Read AviSynth+'s frame properties to set additional info.
     *
     * Due to a bug preventing the C interface from accessing frame
     * properties in earlier versions of interface version 8, and
     * previous attempts at being clever resulting in pre-8 versions
     * of AviSynth+ segfaulting, only enable this if we detect
     * version 9 at the minimum.  Technically, 8.1 works, but the time
     * distance between 8.1 and 9 is very small, so just restrict it to 9. */

    if (avs_library.avs_get_version(avs->clip) >= 9) {

        frame  = avs_library.avs_get_frame(avs->clip, 0);
        avsmap = avs_library.avs_get_frame_props_ro(avs->env, frame);

        /* Field order */
        if(avs->flags & AVISYNTH_FRAMEPROP_FIELD_ORDER) {
            if(avs_library.avs_prop_get_type(avs->env, avsmap, "_FieldBased") == AVS_PROPTYPE_UNSET) {
                st->codecpar->field_order = AV_FIELD_UNKNOWN;
            } else {
                switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_FieldBased", 0, &error)) {
                case 0:
                    st->codecpar->field_order = AV_FIELD_PROGRESSIVE;
                    break;
                case 1:
                    st->codecpar->field_order = AV_FIELD_BB;
                    break;
                case 2:
                    st->codecpar->field_order = AV_FIELD_TT;
                    break;
                default:
                    st->codecpar->field_order = AV_FIELD_UNKNOWN;
                }
            }
        }

        /* Color Range */
        if(avs->flags & AVISYNTH_FRAMEPROP_RANGE) {
            if(avs_library.avs_prop_get_type(avs->env, avsmap, "_ColorRange") == AVS_PROPTYPE_UNSET) {
                st->codecpar->color_range = AVCOL_RANGE_UNSPECIFIED;
            } else {
                switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_ColorRange", 0, &error)) {
                case 0:
                    st->codecpar->color_range = AVCOL_RANGE_JPEG;
                    break;
                case 1:
                    st->codecpar->color_range = AVCOL_RANGE_MPEG;
                    break;
                default:
                    st->codecpar->color_range = AVCOL_RANGE_UNSPECIFIED;
                }
            }
        }

        /* Color Primaries */
        if(avs->flags & AVISYNTH_FRAMEPROP_PRIMARIES) {
            switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_Primaries", 0, &error)) {
            case 1:
                st->codecpar->color_primaries = AVCOL_PRI_BT709;
                break;
            case 2:
                st->codecpar->color_primaries = AVCOL_PRI_UNSPECIFIED;
                break;
            case 4:
                st->codecpar->color_primaries = AVCOL_PRI_BT470M;
                break;
            case 5:
                st->codecpar->color_primaries = AVCOL_PRI_BT470BG;
                break;
            case 6:
                st->codecpar->color_primaries = AVCOL_PRI_SMPTE170M;
                break;
            case 7:
                st->codecpar->color_primaries = AVCOL_PRI_SMPTE240M;
                break;
            case 8:
                st->codecpar->color_primaries = AVCOL_PRI_FILM;
                break;
            case 9:
                st->codecpar->color_primaries = AVCOL_PRI_BT2020;
                break;
            case 10:
                st->codecpar->color_primaries = AVCOL_PRI_SMPTE428;
                break;
            case 11:
                st->codecpar->color_primaries = AVCOL_PRI_SMPTE431;
                break;
            case 12:
                st->codecpar->color_primaries = AVCOL_PRI_SMPTE432;
                break;
            case 22:
                st->codecpar->color_primaries = AVCOL_PRI_EBU3213;
                break;
            default:
                st->codecpar->color_primaries = AVCOL_PRI_UNSPECIFIED;
            }
        }

        /* Color Transfer Characteristics */
        if(avs->flags & AVISYNTH_FRAMEPROP_TRANSFER) {
            switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_Transfer", 0, &error)) {
            case 1:
                st->codecpar->color_trc = AVCOL_TRC_BT709;
                break;
            case 2:
                st->codecpar->color_trc = AVCOL_TRC_UNSPECIFIED;
                break;
            case 4:
                st->codecpar->color_trc = AVCOL_TRC_GAMMA22;
                break;
            case 5:
                st->codecpar->color_trc = AVCOL_TRC_GAMMA28;
                break;
            case 6:
                st->codecpar->color_trc = AVCOL_TRC_SMPTE170M;
                break;
            case 7:
                st->codecpar->color_trc = AVCOL_TRC_SMPTE240M;
                break;
            case 8:
                st->codecpar->color_trc = AVCOL_TRC_LINEAR;
                break;
            case 9:
                st->codecpar->color_trc = AVCOL_TRC_LOG;
                break;
            case 10:
                st->codecpar->color_trc = AVCOL_TRC_LOG_SQRT;
                break;
            case 11:
                st->codecpar->color_trc = AVCOL_TRC_IEC61966_2_4;
                break;
            case 12:
                st->codecpar->color_trc = AVCOL_TRC_BT1361_ECG;
                break;
            case 13:
                st->codecpar->color_trc = AVCOL_TRC_IEC61966_2_1;
                break;
            case 14:
                st->codecpar->color_trc = AVCOL_TRC_BT2020_10;
                break;
            case 15:
                st->codecpar->color_trc = AVCOL_TRC_BT2020_12;
                break;
            case 16:
                st->codecpar->color_trc = AVCOL_TRC_SMPTE2084;
                break;
            case 17:
                st->codecpar->color_trc = AVCOL_TRC_SMPTE428;
                break;
            case 18:
                st->codecpar->color_trc = AVCOL_TRC_ARIB_STD_B67;
                break;
            default:
                st->codecpar->color_trc = AVCOL_TRC_UNSPECIFIED;
            }
        }

        /* Matrix coefficients */
        if(avs->flags & AVISYNTH_FRAMEPROP_MATRIX) {
            if(avs_library.avs_prop_get_type(avs->env, avsmap, "_Matrix") == AVS_PROPTYPE_UNSET) {
                st->codecpar->color_space = AVCOL_SPC_UNSPECIFIED;
            } else {
                switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_Matrix", 0, &error)) {
                case 0:
                    st->codecpar->color_space = AVCOL_SPC_RGB;
                    break;
                case 1:
                    st->codecpar->color_space = AVCOL_SPC_BT709;
                    break;
                case 2:
                    st->codecpar->color_space = AVCOL_SPC_UNSPECIFIED;
                    break;
                case 4:
                    st->codecpar->color_space = AVCOL_SPC_FCC;
                    break;
                case 5:
                    st->codecpar->color_space = AVCOL_SPC_BT470BG;
                    break;
                case 6:
                    st->codecpar->color_space = AVCOL_SPC_SMPTE170M;
                    break;
                case 7:
                    st->codecpar->color_space = AVCOL_SPC_SMPTE240M;
                    break;
                case 8:
                    st->codecpar->color_space = AVCOL_SPC_YCGCO;
                    break;
                case 9:
                    st->codecpar->color_space = AVCOL_SPC_BT2020_NCL;
                    break;
                case 10:
                    st->codecpar->color_space = AVCOL_SPC_BT2020_CL;
                    break;
                case 11:
                    st->codecpar->color_space = AVCOL_SPC_SMPTE2085;
                    break;
                case 12:
                    st->codecpar->color_space = AVCOL_SPC_CHROMA_DERIVED_NCL;
                    break;
                case 13:
                    st->codecpar->color_space = AVCOL_SPC_CHROMA_DERIVED_CL;
                    break;
                case 14:
                    st->codecpar->color_space = AVCOL_SPC_ICTCP;
                    break;
                default:
                    st->codecpar->color_space = AVCOL_SPC_UNSPECIFIED;
                }
            }
        }

        /* Chroma Location */
        if(avs->flags & AVISYNTH_FRAMEPROP_CHROMA_LOCATION) {
            if(avs_library.avs_prop_get_type(avs->env, avsmap, "_ChromaLocation") == AVS_PROPTYPE_UNSET) {
                st->codecpar->chroma_location = AVCHROMA_LOC_UNSPECIFIED;
            } else {
                switch (avs_library.avs_prop_get_int(avs->env, avsmap, "_ChromaLocation", 0, &error)) {
                case 0:
                    st->codecpar->chroma_location = AVCHROMA_LOC_LEFT;
                    break;
                case 1:
                    st->codecpar->chroma_location = AVCHROMA_LOC_CENTER;
                    break;
                case 2:
                    st->codecpar->chroma_location = AVCHROMA_LOC_TOPLEFT;
                    break;
                case 3:
                    st->codecpar->chroma_location = AVCHROMA_LOC_TOP;
                    break;
                case 4:
                    st->codecpar->chroma_location = AVCHROMA_LOC_BOTTOMLEFT;
                    break;
                case 5:
                    st->codecpar->chroma_location = AVCHROMA_LOC_BOTTOM;
                    break;
                default:
                    st->codecpar->chroma_location = AVCHROMA_LOC_UNSPECIFIED;
                }
            }
        }

        /* Sample aspect ratio */
        if(avs->flags & AVISYNTH_FRAMEPROP_SAR) {
            sar_num = avs_library.avs_prop_get_int(avs->env, avsmap, "_SARNum", 0, &error);
            sar_den = avs_library.avs_prop_get_int(avs->env, avsmap, "_SARDen", 0, &error);
            st->sample_aspect_ratio = (AVRational){ sar_num, sar_den };
        }

        avs_library.avs_release_video_frame(frame);
    } else {
        st->codecpar->field_order = AV_FIELD_UNKNOWN;
        /* AviSynth works with frame-based video, detecting field order can
         * only work when avs_is_field_based returns 'false'. */
        av_log(s, AV_LOG_TRACE, "avs_is_field_based: %d\n", avs_is_field_based(avs->vi));
        if (avs_is_field_based(avs->vi) == 0) {
            if (avs_is_tff(avs->vi)) {
                st->codecpar->field_order = AV_FIELD_TT;
            }
            else if (avs_is_bff(avs->vi)) {
                st->codecpar->field_order = AV_FIELD_BB;
            }
        }
    }

    return 0;
}

static int avisynth_create_stream_audio(AVFormatContext *s, AVStream *st)
{
    AviSynthContext *avs = s->priv_data;

    st->codecpar->codec_type            = AVMEDIA_TYPE_AUDIO;
    st->codecpar->sample_rate           = avs->vi->audio_samples_per_second;
    st->codecpar->ch_layout.nb_channels = avs->vi->nchannels;
    st->duration                        = avs->vi->num_audio_samples;
    avpriv_set_pts_info(st, 64, 1, avs->vi->audio_samples_per_second);

    if (avs_library.avs_get_version(avs->clip) >= 10)
        av_channel_layout_from_mask(&st->codecpar->ch_layout,
                                    avs_library.avs_get_channel_mask(avs->vi));

    switch (avs->vi->sample_type) {
    case AVS_SAMPLE_INT8:
        st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
        break;
    case AVS_SAMPLE_INT16:
        st->codecpar->codec_id = PCM(S16);
        break;
    case AVS_SAMPLE_INT24:
        st->codecpar->codec_id = PCM(S24);
        break;
    case AVS_SAMPLE_INT32:
        st->codecpar->codec_id = PCM(S32);
        break;
    case AVS_SAMPLE_FLOAT:
        st->codecpar->codec_id = PCM(F32);
        break;
    default:
        av_log(s, AV_LOG_ERROR,
               "unknown AviSynth sample type %d\n", avs->vi->sample_type);
        avs->error = 1;
        return AVERROR_UNKNOWN;
    }
    return 0;
}

static int avisynth_create_stream(AVFormatContext *s)
{
    AviSynthContext *avs = s->priv_data;
    AVStream *st;
    int ret;
    int id = 0;

    if (avs_has_video(avs->vi)) {
        st = avformat_new_stream(s, NULL);
        if (!st)
            return AVERROR_UNKNOWN;
        st->id = id++;
        if (ret = avisynth_create_stream_video(s, st))
            return ret;
    }
    if (avs_has_audio(avs->vi)) {
        st = avformat_new_stream(s, NULL);
        if (!st)
            return AVERROR_UNKNOWN;
        st->id = id++;
        if (ret = avisynth_create_stream_audio(s, st))
            return ret;
    }
    return 0;
}

static int avisynth_open_file(AVFormatContext *s)
{
    AviSynthContext *avs = s->priv_data;
    AVS_Value val;
    int ret;

    if (ret = avisynth_context_create(s))
        return ret;

    if (!avs_library.avs_check_version(avs->env, 7)) {
        AVS_Value args[] = {
            avs_new_value_string(s->url),
            avs_new_value_bool(1) // filename is in UTF-8
        };
        val = avs_library.avs_invoke(avs->env, "Import",
                                     avs_new_value_array(args, 2), 0);
    } else {
        AVS_Value arg;
#ifdef _WIN32
        char *filename_ansi;
        /* Convert UTF-8 to ANSI code page */
        if (utf8toansi(s->url, &filename_ansi)) {
            ret = AVERROR_UNKNOWN;
            goto fail;
        }
        arg = avs_new_value_string(filename_ansi);
#else
        arg = avs_new_value_string(s->url);
#endif
        val = avs_library.avs_invoke(avs->env, "Import", arg, 0);
#ifdef _WIN32
        av_free(filename_ansi);
#endif
    }

    if (avs_is_error(val)) {
        av_log(s, AV_LOG_ERROR, "%s\n", avs_as_error(val));
        ret = AVERROR_UNKNOWN;
        goto fail;
    }
    if (!avs_is_clip(val)) {
        av_log(s, AV_LOG_ERROR, "AviSynth script did not return a clip\n");
        ret = AVERROR_UNKNOWN;
        goto fail;
    }

    avs->clip = avs_library.avs_take_clip(val, avs->env);
    avs->vi   = avs_library.avs_get_video_info(avs->clip);

    /* On Windows, FFmpeg supports AviSynth interface version 6 or higher.
     * This includes AviSynth 2.6 RC1 or higher, and AviSynth+ r1718 or higher,
     * and excludes 2.5 and the 2.6 alphas. */

    if (avs_library.avs_get_version(avs->clip) < 6) {
        av_log(s, AV_LOG_ERROR,
               "AviSynth version is too old. Please upgrade to either AviSynth 2.6 >= RC1 or AviSynth+ >= r1718.\n");
        ret = AVERROR_UNKNOWN;
        goto fail;
    }

    /* Release the AVS_Value as it will go out of scope. */
    avs_library.avs_release_value(val);

    if (ret = avisynth_create_stream(s))
        goto fail;

    return 0;

fail:
    avisynth_context_destroy(avs);
    return ret;
}

static void avisynth_next_stream(AVFormatContext *s, AVStream **st,
                                 AVPacket *pkt, int *discard)
{
    AviSynthContext *avs = s->priv_data;

    avs->curr_stream++;
    avs->curr_stream %= s->nb_streams;

    *st = s->streams[avs->curr_stream];
    if ((*st)->discard == AVDISCARD_ALL)
        *discard = 1;
    else
        *discard = 0;

    return;
}

/* Copy AviSynth clip data into an AVPacket. */
static int avisynth_read_packet_video(AVFormatContext *s, AVPacket *pkt,
                                      int discard)
{
    AviSynthContext *avs = s->priv_data;
    AVS_VideoFrame *frame;
    unsigned char *dst_p;
    const unsigned char *src_p;
    int n, i, plane, rowsize, planeheight, pitch, bits, ret;
    const char *error;

    if (avs->curr_frame >= avs->vi->num_frames)
        return AVERROR_EOF;

    /* This must happen even if the stream is discarded to prevent desync. */
    n = avs->curr_frame++;
    if (discard)
        return 0;

    bits = avs_library.avs_bits_per_pixel(avs->vi);

    /* Without the cast to int64_t, calculation overflows at about 9k x 9k
     * resolution. */
    pkt->size = (((int64_t)avs->vi->width *
                  (int64_t)avs->vi->height) * bits) / 8;
    if (!pkt->size)
        return AVERROR_UNKNOWN;

    if ((ret = av_new_packet(pkt, pkt->size)) < 0)
        return ret;

    pkt->pts      = n;
    pkt->dts      = n;
    pkt->duration = 1;
    pkt->stream_index = avs->curr_stream;

    frame = avs_library.avs_get_frame(avs->clip, n);
    error = avs_library.avs_clip_get_error(avs->clip);
    if (error) {
        av_log(s, AV_LOG_ERROR, "%s\n", error);
        avs->error = 1;
        av_packet_unref(pkt);
        return AVERROR_UNKNOWN;
    }

    dst_p = pkt->data;
    for (i = 0; i < avs->n_planes; i++) {
        plane = avs->planes[i];
        src_p = avs_library.avs_get_read_ptr_p(frame, plane);
        pitch = avs_library.avs_get_pitch_p(frame, plane);

        rowsize     = avs_library.avs_get_row_size_p(frame, plane);
        planeheight = avs_library.avs_get_height_p(frame, plane);

        /* Flip RGB video. */
        if (avs_library.avs_is_color_space(avs->vi, AVS_CS_BGR)   ||
            avs_library.avs_is_color_space(avs->vi, AVS_CS_BGR48) ||
            avs_library.avs_is_color_space(avs->vi, AVS_CS_BGR64)) {
            src_p = src_p + (planeheight - 1) * pitch;
            pitch = -pitch;
        }

        avs_library.avs_bit_blt(avs->env, dst_p, rowsize, src_p, pitch,
                                 rowsize, planeheight);
        dst_p += rowsize * planeheight;
    }

    avs_library.avs_release_video_frame(frame);
    return 0;
}

static int avisynth_read_packet_audio(AVFormatContext *s, AVPacket *pkt,
                                      int discard)
{
    AviSynthContext *avs = s->priv_data;
    AVRational fps, samplerate;
    int samples, ret;
    int64_t n;
    const char *error;

    if (avs->curr_sample >= avs->vi->num_audio_samples)
        return AVERROR_EOF;

    fps.num        = avs->vi->fps_numerator;
    fps.den        = avs->vi->fps_denominator;
    samplerate.num = avs->vi->audio_samples_per_second;
    samplerate.den = 1;

    if (avs_has_video(avs->vi)) {
        if (avs->curr_frame < avs->vi->num_frames)
            samples = av_rescale_q(avs->curr_frame, samplerate, fps) -
                      avs->curr_sample;
        else
            samples = av_rescale_q(1, samplerate, fps);
    } else {
        samples = 1000;
    }

    /* After seeking, audio may catch up with video. */
    if (samples <= 0) {
        pkt->size = 0;
        pkt->data = NULL;
        return 0;
    }

    if (avs->curr_sample + samples > avs->vi->num_audio_samples)
        samples = avs->vi->num_audio_samples - avs->curr_sample;

    /* This must happen even if the stream is discarded to prevent desync. */
    n                 = avs->curr_sample;
    avs->curr_sample += samples;
    if (discard)
        return 0;

    pkt->size = avs_bytes_per_channel_sample(avs->vi) *
                samples * avs->vi->nchannels;
    if (!pkt->size)
        return AVERROR_UNKNOWN;

    if ((ret = av_new_packet(pkt, pkt->size)) < 0)
        return ret;

    pkt->pts      = n;
    pkt->dts      = n;
    pkt->duration = samples;
    pkt->stream_index = avs->curr_stream;

    avs_library.avs_get_audio(avs->clip, pkt->data, n, samples);
    error = avs_library.avs_clip_get_error(avs->clip);
    if (error) {
        av_log(s, AV_LOG_ERROR, "%s\n", error);
        avs->error = 1;
        av_packet_unref(pkt);
        return AVERROR_UNKNOWN;
    }
    return 0;
}

static av_cold int avisynth_read_header(AVFormatContext *s)
{
    int ret;

    // Calling library must implement a lock for thread-safe opens.
    if (ff_mutex_lock(&avisynth_mutex))
        return AVERROR_UNKNOWN;

    if (ret = avisynth_open_file(s)) {
        ff_mutex_unlock(&avisynth_mutex);
        return ret;
    }

    ff_mutex_unlock(&avisynth_mutex);
    return 0;
}

static int avisynth_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    AviSynthContext *avs = s->priv_data;
    AVStream *st;
    int discard = 0;
    int ret;

    if (avs->error)
        return AVERROR_UNKNOWN;

    /* If either stream reaches EOF, try to read the other one before
     * giving up. */
    avisynth_next_stream(s, &st, pkt, &discard);
    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
        ret = avisynth_read_packet_video(s, pkt, discard);
        if (ret == AVERROR_EOF && avs_has_audio(avs->vi)) {
            avisynth_next_stream(s, &st, pkt, &discard);
            return avisynth_read_packet_audio(s, pkt, discard);
        }
    } else {
        ret = avisynth_read_packet_audio(s, pkt, discard);
        if (ret == AVERROR_EOF && avs_has_video(avs->vi)) {
            avisynth_next_stream(s, &st, pkt, &discard);
            return avisynth_read_packet_video(s, pkt, discard);
        }
    }

    return ret;
}

static av_cold int avisynth_read_close(AVFormatContext *s)
{
    if (ff_mutex_lock(&avisynth_mutex))
        return AVERROR_UNKNOWN;

    avisynth_context_destroy(s->priv_data);
    ff_mutex_unlock(&avisynth_mutex);
    return 0;
}

static int avisynth_read_seek(AVFormatContext *s, int stream_index,
                              int64_t timestamp, int flags)
{
    AviSynthContext *avs = s->priv_data;
    AVStream *st;
    AVRational fps, samplerate;

    if (avs->error)
        return AVERROR_UNKNOWN;

    fps        = (AVRational) { avs->vi->fps_numerator,
                                avs->vi->fps_denominator };
    samplerate = (AVRational) { avs->vi->audio_samples_per_second, 1 };

    st = s->streams[stream_index];
    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
        /* AviSynth frame counts are signed int. */
        if ((timestamp >= avs->vi->num_frames) ||
            (timestamp > INT_MAX)              ||
            (timestamp < 0))
            return AVERROR_EOF;
        avs->curr_frame = timestamp;
        if (avs_has_audio(avs->vi))
            avs->curr_sample = av_rescale_q(timestamp, samplerate, fps);
    } else {
        if ((timestamp >= avs->vi->num_audio_samples) || (timestamp < 0))
            return AVERROR_EOF;
        /* Force frame granularity for seeking. */
        if (avs_has_video(avs->vi)) {
            avs->curr_frame  = av_rescale_q(timestamp, fps, samplerate);
            avs->curr_sample = av_rescale_q(avs->curr_frame, samplerate, fps);
        } else {
            avs->curr_sample = timestamp;
        }
    }

    return 0;
}

#define AVISYNTH_FRAMEPROP_DEFAULT AVISYNTH_FRAMEPROP_FIELD_ORDER | AVISYNTH_FRAMEPROP_RANGE | \
                                   AVISYNTH_FRAMEPROP_PRIMARIES | AVISYNTH_FRAMEPROP_TRANSFER | \
                                   AVISYNTH_FRAMEPROP_MATRIX | AVISYNTH_FRAMEPROP_CHROMA_LOCATION
#define OFFSET(x) offsetof(AviSynthContext, x)
static const AVOption avisynth_options[] = {
    { "avisynth_flags", "set flags related to reading frame properties from script (AviSynth+ v3.7.1 or higher)", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = AVISYNTH_FRAMEPROP_DEFAULT}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "field_order", "read field order", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_FIELD_ORDER}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "range", "read color range", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_RANGE}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "primaries", "read color primaries", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_PRIMARIES}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "transfer", "read color transfer characteristics", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_TRANSFER}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "matrix", "read matrix coefficients", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_MATRIX}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "chroma_location", "read chroma location", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_CHROMA_LOCATION}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { "sar", "read sample aspect ratio", 0, AV_OPT_TYPE_CONST, {.i64 = AVISYNTH_FRAMEPROP_SAR}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "flags" },
    { NULL },
};

static const AVClass avisynth_demuxer_class = {
    .class_name = "AviSynth demuxer",
    .item_name  = av_default_item_name,
    .option     = avisynth_options,
    .version    = LIBAVUTIL_VERSION_INT,
};

const FFInputFormat ff_avisynth_demuxer = {
    .p.name         = "avisynth",
    .p.long_name    = NULL_IF_CONFIG_SMALL("AviSynth script"),
    .p.extensions   = "avs",
    .p.priv_class   = &avisynth_demuxer_class,
    .priv_data_size = sizeof(AviSynthContext),
    .read_header    = avisynth_read_header,
    .read_packet    = avisynth_read_packet,
    .read_close     = avisynth_read_close,
    .read_seek      = avisynth_read_seek,
};