summaryrefslogtreecommitdiffstats
path: root/video/img_format.c
blob: a48d700e3ea10d522e57a27b2c24c32aaafcb4e6 (plain)
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
/*
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <assert.h>
#include <string.h>

#include <libavcodec/avcodec.h>
#include <libavutil/imgutils.h>
#include <libavutil/pixfmt.h>
#include <libavutil/pixdesc.h>

#include "config.h"

#include "video/img_format.h"
#include "video/mp_image.h"
#include "video/fmt-conversion.h"

struct mp_imgfmt_entry {
    const char *name;
    // Valid if flags!=0.
    // This can be incomplete, and missing fields are filled in:
    //  - sets num_planes and bpp[], derived from comps[] (rounds to bytes)
    //  - sets MP_IMGFLAG_GRAY, derived from comps[]
    //  - sets MP_IMGFLAG_ALPHA, derived from comps[]
    //  - sets align_x/y if 0, derived from chroma shift
    //  - sets xs[]/ys[] always, derived from num_planes/chroma_shift
    //  - sets MP_IMGFLAG_HAS_COMPS|MP_IMGFLAG_NE if num_planes>0
    //  - sets MP_IMGFLAG_TYPE_UINT if no other type set
    //  - sets id to mp_imgfmt_list[] implied format
    struct mp_imgfmt_desc desc;
};

#define FRINGE_GBRP(def, dname, b)                                          \
    [def - IMGFMT_CUST_BASE] = {                                            \
        .name = dname,                                                      \
        .desc = { .flags = MP_IMGFLAG_COLOR_RGB,                            \
                  .comps = { {2, 0, 8, (b) - 8}, {0, 0, 8, (b) - 8},        \
                             {1, 0, 8, (b) - 8}, }, }}

#define FLOAT_YUV(def, dname, xs, ys, a)                                    \
    [def - IMGFMT_CUST_BASE] = {                                            \
        .name = dname,                                                      \
        .desc = { .flags = MP_IMGFLAG_COLOR_YUV | MP_IMGFLAG_TYPE_FLOAT,    \
                   .chroma_xs = xs, .chroma_ys = ys,                        \
                   .comps = { {0, 0, 32}, {1, 0, 32}, {2, 0, 32},           \
                              {3 * (a), 0, 32 * (a)} }, }}

static const struct mp_imgfmt_entry mp_imgfmt_list[] = {
    // not in ffmpeg
    [IMGFMT_VDPAU_OUTPUT - IMGFMT_CUST_BASE] = {
        .name = "vdpau_output",
        .desc = {
            .flags = MP_IMGFLAG_NE | MP_IMGFLAG_RGB | MP_IMGFLAG_HWACCEL,
        },
    },
    [IMGFMT_RGB30 - IMGFMT_CUST_BASE] = {
        .name = "rgb30",
        .desc = {
            .flags = MP_IMGFLAG_RGB,
            .comps = { {0, 20, 10}, {0, 10, 10}, {0, 0, 10} },
        },
    },
    [IMGFMT_YAP8 - IMGFMT_CUST_BASE] = {
        .name = "yap8",
        .desc = {
            .flags = MP_IMGFLAG_COLOR_YUV,
            .comps = { {0, 0, 8}, {0}, {0}, {1, 0, 8} },
        },
    },
    [IMGFMT_YAP16 - IMGFMT_CUST_BASE] = {
        .name = "yap16",
        .desc = {
            .flags = MP_IMGFLAG_COLOR_YUV,
            .comps = { {0, 0, 16}, {0}, {0}, {1, 0, 16} },
        },
    },
    [IMGFMT_Y1 - IMGFMT_CUST_BASE] = {
        .name = "y1",
        .desc = {
            .flags = MP_IMGFLAG_COLOR_RGB,
            .comps = { {0, 0, 8, -7} },
        },
    },
    [IMGFMT_YAPF - IMGFMT_CUST_BASE] = {
        .name = "grayaf32", // try to mimic ffmpeg naming convention
        .desc = {
            .flags = MP_IMGFLAG_COLOR_YUV | MP_IMGFLAG_TYPE_FLOAT,
            .comps = { {0, 0, 32}, {0}, {0}, {1, 0, 32} },
        },
    },
    FLOAT_YUV(IMGFMT_444PF,  "yuv444pf",  0, 0, 0),
    FLOAT_YUV(IMGFMT_444APF, "yuva444pf", 0, 0, 1),
    FLOAT_YUV(IMGFMT_420PF,  "yuv420pf",  1, 1, 0),
    FLOAT_YUV(IMGFMT_420APF, "yuva420pf", 1, 1, 1),
    FLOAT_YUV(IMGFMT_422PF,  "yuv422pf",  1, 0, 0),
    FLOAT_YUV(IMGFMT_422APF, "yuva422pf", 1, 0, 1),
    FLOAT_YUV(IMGFMT_440PF,  "yuv440pf",  0, 1, 0),
    FLOAT_YUV(IMGFMT_440APF, "yuva440pf", 0, 1, 1),
    FLOAT_YUV(IMGFMT_410PF,  "yuv410pf",  2, 2, 0),
    FLOAT_YUV(IMGFMT_410APF, "yuva410pf", 2, 2, 1),
    FLOAT_YUV(IMGFMT_411PF,  "yuv411pf",  2, 0, 0),
    FLOAT_YUV(IMGFMT_411APF, "yuva411pf", 2, 0, 1),
    FRINGE_GBRP(IMGFMT_GBRP1, "gbrp1", 1),
    FRINGE_GBRP(IMGFMT_GBRP2, "gbrp2", 2),
    FRINGE_GBRP(IMGFMT_GBRP3, "gbrp3", 3),
    FRINGE_GBRP(IMGFMT_GBRP4, "gbrp4", 4),
    FRINGE_GBRP(IMGFMT_GBRP5, "gbrp5", 5),
    FRINGE_GBRP(IMGFMT_GBRP6, "gbrp6", 6),
    // in FFmpeg, but FFmpeg names have an annoying "_vld" suffix
    [IMGFMT_VIDEOTOOLBOX - IMGFMT_CUST_BASE] = {
        .name = "videotoolbox",
    },
    [IMGFMT_VAAPI - IMGFMT_CUST_BASE] = {
        .name = "vaapi",
    },
};

static const struct mp_imgfmt_entry *get_mp_desc(int imgfmt)
{
    if (imgfmt < IMGFMT_CUST_BASE)
        return NULL;
    int index = imgfmt - IMGFMT_CUST_BASE;
    if (index >= MP_ARRAY_SIZE(mp_imgfmt_list))
        return NULL;
    const struct mp_imgfmt_entry *e = &mp_imgfmt_list[index];
    return e->name ? e : NULL;
}

char **mp_imgfmt_name_list(void)
{
    int count = IMGFMT_END - IMGFMT_START;
    char **list = talloc_zero_array(NULL, char *, count + 1);
    int num = 0;
    for (int n = IMGFMT_START; n < IMGFMT_END; n++) {
        const char *name = mp_imgfmt_to_name(n);
        if (strcmp(name, "unknown") != 0)
            list[num++] = talloc_strdup(list, name);
    }
    return list;
}

int mp_imgfmt_from_name(bstr name)
{
    if (bstr_equals0(name, "none"))
        return 0;
    for (int n = 0; n < MP_ARRAY_SIZE(mp_imgfmt_list); n++) {
        const struct mp_imgfmt_entry *p = &mp_imgfmt_list[n];
        if (p->name && bstr_equals0(name, p->name))
            return IMGFMT_CUST_BASE + n;
    }
    return pixfmt2imgfmt(av_get_pix_fmt(mp_tprintf(80, "%.*s", BSTR_P(name))));
}

char *mp_imgfmt_to_name_buf(char *buf, size_t buf_size, int fmt)
{
    const struct mp_imgfmt_entry *p = get_mp_desc(fmt);
    const char *name = p ? p->name : NULL;
    if (!name) {
        const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(imgfmt2pixfmt(fmt));
        if (pixdesc)
            name = pixdesc->name;
    }
    if (!name)
        name = "unknown";
    snprintf(buf, buf_size, "%s", name);
    int len = strlen(buf);
    if (len > 2 && buf[len - 2] == MP_SELECT_LE_BE('l', 'b') && buf[len - 1] == 'e')
        buf[len - 2] = '\0';
    return buf;
}

static void fill_pixdesc_layout(struct mp_imgfmt_desc *desc,
                                enum AVPixelFormat fmt,
                                const AVPixFmtDescriptor *pd)
{
    if (pd->flags & AV_PIX_FMT_FLAG_PAL ||
        pd->flags & AV_PIX_FMT_FLAG_HWACCEL)
        goto fail;

    bool has_alpha = pd->flags & AV_PIX_FMT_FLAG_ALPHA;
    if (pd->nb_components != 1 + has_alpha &&
        pd->nb_components != 3 + has_alpha)
        goto fail;

    // Very convenient: we assume we're always on little endian, and FFmpeg
    // explicitly marks big endian formats => don't need to guess whether a
    // format is little endian, or not affected by byte order.
    bool is_be = pd->flags & AV_PIX_FMT_FLAG_BE;
    bool is_ne = MP_SELECT_LE_BE(false, true) == is_be;

    // Packed sub-sampled YUV is very... special.
    bool is_packed_ss_yuv = pd->log2_chroma_w && !pd->log2_chroma_h &&
        pd->comp[1].plane == 0 && pd->comp[2].plane == 0 &&
        pd->nb_components == 3;

    if (is_packed_ss_yuv)
        desc->bpp[0] = pd->comp[1].step * 8;

    // Determine if there are any byte overlaps => relevant for determining
    // access unit for endian, since pixdesc does not expose this, and assumes
    // a weird model where you do separate memory fetches for each component.
    bool any_shared_bytes = !!(pd->flags & AV_PIX_FMT_FLAG_BITSTREAM);
    for (int c = 0; c < pd->nb_components; c++) {
        for (int i = 0; i < c; i++) {
            const AVComponentDescriptor *d1 = &pd->comp[c];
            const AVComponentDescriptor *d2 = &pd->comp[i];
            if (d1->plane == d2->plane) {
                if (d1->offset + (d1->depth + 7) / 8u > d2->offset &&
                    d2->offset + (d2->depth + 7) / 8u > d1->offset)
                    any_shared_bytes = true;
            }
        }
    }

    int el_bits = (pd->flags & AV_PIX_FMT_FLAG_BITSTREAM) ? 1 : 8;
    for (int c = 0; c < pd->nb_components; c++) {
        const AVComponentDescriptor *d = &pd->comp[c];
        if (d->plane >= MP_MAX_PLANES)
            goto fail;

        desc->num_planes = MPMAX(desc->num_planes, d->plane + 1);

        int plane_bits = desc->bpp[d->plane];
        int c_bits = d->step * el_bits;

        // The first component wins, because either all components result in
        // the same value, or luma wins (luma always comes before chroma).
        if (plane_bits) {
            if (c_bits > plane_bits)
                goto fail; // inconsistent
        } else {
            desc->bpp[d->plane] = plane_bits = c_bits;
        }

        int shift = d->shift;
        // What the fuck: for some inexplicable reason, MONOB uses shift=7
        // in pixdesc, which is basically out of bounds. Pixdesc bug?
        // Make it behave like MONOW. (No, the bit-order is not different.)
        if (fmt == AV_PIX_FMT_MONOBLACK)
            shift = 0;

        int offset = d->offset * el_bits;
        // The pixdesc logic for reading and endian swapping is as follows
        // (reverse engineered from av_read_image_line2()):
        // - determine a word size that will include the component fully;
        //   this includes the "active" bits and the amount "shifted" away
        //   (for example shift=7/depth=18 => 32 bit word reading [31:0])
        // - the same format can use different word sizes (e.g. bgr565: the R
        //   component at offset 0 is read as 8 bit; BG is read as 16 bits)
        // - if BE flag is set, swap the word before proceeding
        // - extract via shift and mask derived by depth
        int word = mp_round_next_power_of_2(MPMAX(d->depth + shift, 8));
        // The purpose of this is unknown. It's an absurdity fished out of
        // av_read_image_line2()'s implementation. It seems technically
        // unnecessary, and provides no information. On the other hand, it
        // compensates for seemingly bogus packed integer pixdescs; this
        // is "why" some formats use d->offset = -1.
        if (is_be && el_bits == 8 && word == 8)
            offset += 8;
        // Pixdesc's model sometimes requires accesses with varying word-sizes,
        // as seen in bgr565 and other formats. Also, it makes you read some
        // formats with multiple endian-dependent accesses, where accessing a
        // larger unit would make more sense. (Consider X2RGB10BE, for which
        // pixdesc wants you to perform 3 * 2 byte accesses, and swap each of
        // the read 16 bit words. What you really want is to swap the entire 4
        // byte thing, and then extract the components with bit shifts).
        // This is complete bullshit, so we transform it into word swaps before
        // further processing. Care needs to be taken to not change formats like
        // P010 or YA16 (prefer component accesses for them; P010 isn't even
        // representable, because endian_shift is for all planes).
        // As a heuristic, assume that if any components share a byte, the whole
        // pixel is read as a single memory access and endian swapped at once.
        int access_size = 8;
        if (plane_bits > 8) {
            if (any_shared_bytes) {
                access_size = plane_bits;
                if (is_be && word != access_size) {
                    // Before: offset = 8*byte_offset (with word bits of data)
                    // After: offset = bit_offset into swapped endian_size word
                    offset = access_size - word - offset;
                }
            } else {
                access_size = word;
            }
        }
        int endian_size = (access_size && !is_ne) ? access_size : 8;
        int endian_shift = mp_log2(endian_size) - 3;
        if (!MP_IS_POWER_OF_2(endian_size) || endian_shift < 0 || endian_shift > 3)
            goto fail;
        if (desc->endian_shift && desc->endian_shift != endian_shift)
            goto fail;
        desc->endian_shift = endian_shift;

        // We always use bit offsets; this doesn't lose any information,
        // and pixdesc is merely more redundant.
        offset += shift;
        if (offset < 0 || offset >= (1 << 6))
            goto fail;
        if (offset + d->depth > plane_bits)
            goto fail;
        if (d->depth < 0 || d->depth >= (1 << 6))
            goto fail;
        desc->comps[c] = (struct mp_imgfmt_comp_desc){
            .plane = d->plane,
            .offset = offset,
            .size = d->depth,
        };
    }

    for (int p = 0; p < desc->num_planes; p++) {
        if (!desc->bpp[p])
            goto fail; // plane doesn't exist
    }

    // What the fuck: this is probably a pixdesc bug, so fix it.
    if (fmt == AV_PIX_FMT_RGB8) {
        desc->comps[2] = (struct mp_imgfmt_comp_desc){0, 0, 2};
        desc->comps[1] = (struct mp_imgfmt_comp_desc){0, 2, 3};
        desc->comps[0] = (struct mp_imgfmt_comp_desc){0, 5, 3};
    }

    // Overlap test. If any shared bits are happening, this is not a format we
    // can represent (or it's something like Bayer: components in the same bits,
    // but different alternating lines).
    bool any_shared_bits = false;
    for (int c = 0; c < pd->nb_components; c++) {
        for (int i = 0; i < c; i++) {
            struct mp_imgfmt_comp_desc *c1 = &desc->comps[c];
            struct mp_imgfmt_comp_desc *c2 = &desc->comps[i];
            if (c1->plane == c2->plane) {
                if (c1->offset + c1->size > c2->offset &&
                    c2->offset + c2->size > c1->offset)
                    any_shared_bits = true;
            }
        }
    }

    if (any_shared_bits) {
        for (int c = 0; c < pd->nb_components; c++)
            desc->comps[c] = (struct mp_imgfmt_comp_desc){0};
    }

    // Many important formats have padding within an access word. For example
    // yuv420p10 has the upper 6 bit cleared to 0; P010 has the lower 6 bits
    // cleared to 0. Pixdesc cannot represent that these bits are 0. There are
    // other formats where padding is not guaranteed to be 0, but they are
    // described in the same way.
    // Apply a heuristic that is supposed to identify formats which use
    // guaranteed 0 padding. This could fail, but nobody said this pixdesc crap
    // is robust.
    for (int c = 0; c < pd->nb_components; c++) {
        struct mp_imgfmt_comp_desc *cd = &desc->comps[c];
        // Note: rgb444 would defeat our heuristic if we checked only per comp.
        //       also, exclude "bitstream" formats due to monow/monob
        int fsize = MP_ALIGN_UP(cd->size, 8);
        if (!any_shared_bytes && el_bits == 8 && fsize != cd->size &&
            fsize - cd->size <= (1 << 3))
        {
            if (!(cd->offset % 8u)) {
                cd->pad = -(fsize - cd->size);
                cd->size = fsize;
            } else if (!((cd->offset + cd->size) % 8u)) {
                cd->pad = fsize - cd->size;
                cd->size = fsize;
                cd->offset = MP_ALIGN_DOWN(cd->offset, 8);
            }
        }
    }

    // The alpha component always has ID 4 (index 3) in our representation, so
    // move the alpha component to there.
    if (has_alpha && pd->nb_components < 4) {
        desc->comps[3] = desc->comps[pd->nb_components - 1];
        desc->comps[pd->nb_components - 1] = (struct mp_imgfmt_comp_desc){0};
    }

    if (is_packed_ss_yuv) {
        desc->flags |= MP_IMGFLAG_PACKED_SS_YUV;
        desc->bpp[0] /= 1 << pd->log2_chroma_w;
    } else if (!any_shared_bits) {
        desc->flags |= MP_IMGFLAG_HAS_COMPS;
    }

    return;

fail:
    for (int n = 0; n < 4; n++)
        desc->comps[n] = (struct mp_imgfmt_comp_desc){0};
    // Average bit size fallback.
    desc->num_planes = av_pix_fmt_count_planes(fmt);
    for (int p = 0; p < desc->num_planes; p++) {
        int ls = av_image_get_linesize(fmt, 256, p);
        desc->bpp[p] = ls > 0 ? ls * 8 / 256 : 0;
    }
}

static bool mp_imgfmt_get_desc_from_pixdesc(int mpfmt, struct mp_imgfmt_desc *out)
{
    enum AVPixelFormat fmt = imgfmt2pixfmt(mpfmt);
    const AVPixFmtDescriptor *pd = av_pix_fmt_desc_get(fmt);
    if (!pd || pd->nb_components > 4)
        return false;

    struct mp_imgfmt_desc desc = {
        .id = mpfmt,
        .chroma_xs = pd->log2_chroma_w,
        .chroma_ys = pd->log2_chroma_h,
    };

    if (pd->flags & AV_PIX_FMT_FLAG_ALPHA)
        desc.flags |= MP_IMGFLAG_ALPHA;

    if (pd->flags & AV_PIX_FMT_FLAG_HWACCEL)
        desc.flags |= MP_IMGFLAG_TYPE_HW;

    // Pixdesc does not provide a flag for XYZ, so this is the best we can do.
    if (strncmp(pd->name, "xyz", 3) == 0) {
        desc.flags |= MP_IMGFLAG_COLOR_XYZ;
    } else if (pd->flags & AV_PIX_FMT_FLAG_RGB) {
        desc.flags |= MP_IMGFLAG_COLOR_RGB;
    } else if (fmt == AV_PIX_FMT_MONOBLACK || fmt == AV_PIX_FMT_MONOWHITE) {
        desc.flags |= MP_IMGFLAG_COLOR_RGB;
    } else if (fmt == AV_PIX_FMT_PAL8) {
        desc.flags |= MP_IMGFLAG_COLOR_RGB | MP_IMGFLAG_TYPE_PAL8;
    }

    if (pd->flags & AV_PIX_FMT_FLAG_FLOAT)
        desc.flags |= MP_IMGFLAG_TYPE_FLOAT;

    // Educated guess.
    if (!(desc.flags & MP_IMGFLAG_COLOR_MASK) &&
        !(desc.flags & MP_IMGFLAG_TYPE_HW))
        desc.flags |= MP_IMGFLAG_COLOR_YUV;

    desc.align_x = 1 << desc.chroma_xs;
    desc.align_y = 1 << desc.chroma_ys;

    fill_pixdesc_layout(&desc, fmt, pd);

    if (desc.flags & (MP_IMGFLAG_HAS_COMPS | MP_IMGFLAG_PACKED_SS_YUV)) {
        if (!(desc.flags & MP_IMGFLAG_TYPE_MASK))
            desc.flags |= MP_IMGFLAG_TYPE_UINT;
    }

    if (desc.bpp[0] % 8u && (pd->flags & AV_PIX_FMT_FLAG_BITSTREAM))
        desc.align_x = 8 / desc.bpp[0]; // expect power of 2

    // Very heuristical.
    bool is_ne = !desc.endian_shift;
    bool need_endian = (desc.comps[0].size % 8u && desc.bpp[0] > 8) ||
                       desc.comps[0].size > 8;

    if (need_endian) {
        bool is_le = MP_SELECT_LE_BE(is_ne, !is_ne);
        desc.flags |= is_le ? MP_IMGFLAG_LE : MP_IMGFLAG_BE;
    } else {
        desc.flags |= MP_IMGFLAG_LE | MP_IMGFLAG_BE;
    }

    *out = desc;
    return true;
}

bool mp_imgfmt_get_packed_yuv_locations(int imgfmt, uint8_t *luma_offsets)
{
    struct mp_imgfmt_desc desc = mp_imgfmt_get_desc(imgfmt);
    if (!(desc.flags & MP_IMGFLAG_PACKED_SS_YUV))
        return false;

    assert(desc.num_planes == 1);

    // Guess at which positions the additional luma samples are. We iterate
    // starting with the first byte, and then put a luma sample at places
    // not covered by other luma/chroma.
    // Pixdesc does not and can not provide this information. This heuristic
    // may fail in certain cases. What a load of bullshit, right?
    int lsize = desc.comps[0].size;
    int cur_offset = 0;
    for (int lsample = 1; lsample < (1 << desc.chroma_xs); lsample++) {
        while (1) {
            if (cur_offset + lsize > desc.bpp[0] * desc.align_x)
                return false;
            bool free = true;
            for (int c = 0; c < 3; c++) {
                struct mp_imgfmt_comp_desc *cd = &desc.comps[c];
                if (!cd->size)
                    continue;
                if (cd->offset + cd->size > cur_offset &&
                    cur_offset + lsize > cd->offset)
                {
                    free = false;
                    break;
                }
            }
            if (free)
                break;
            cur_offset += lsize;
        }
        luma_offsets[lsample] = cur_offset;
        cur_offset += lsize;
    }

    luma_offsets[0] = desc.comps[0].offset;
    return true;
}

static bool get_native_desc(int mpfmt, struct mp_imgfmt_desc *desc)
{
    const struct mp_imgfmt_entry *p = get_mp_desc(mpfmt);
    if (!p || !p->desc.flags)
        return false;

    *desc = p->desc;

    // Fill in some fields mp_imgfmt_entry.desc is not required to set.

    desc->id = mpfmt;

    for (int n = 0; n < MP_NUM_COMPONENTS; n++) {
        struct mp_imgfmt_comp_desc *cd = &desc->comps[n];
        if (cd->size)
            desc->num_planes = MPMAX(desc->num_planes, cd->plane + 1);
        desc->bpp[cd->plane] =
            MPMAX(desc->bpp[cd->plane], MP_ALIGN_UP(cd->offset + cd->size, 8));
    }

    if (!desc->align_x && !desc->align_y) {
        desc->align_x = 1 << desc->chroma_xs;
        desc->align_y = 1 << desc->chroma_ys;
    }

    if (desc->num_planes)
        desc->flags |= MP_IMGFLAG_HAS_COMPS | MP_IMGFLAG_NE;

    if (!(desc->flags & MP_IMGFLAG_TYPE_MASK))
        desc->flags |= MP_IMGFLAG_TYPE_UINT;

    return true;
}

int mp_imgfmt_desc_get_num_comps(struct mp_imgfmt_desc *desc)
{
    int flags = desc->flags;
    if (!(flags & MP_IMGFLAG_COLOR_MASK))
        return 0;
    return 3 + (flags & MP_IMGFLAG_GRAY ? -2 : 0) + !!(flags & MP_IMGFLAG_ALPHA);
}

struct mp_imgfmt_desc mp_imgfmt_get_desc(int mpfmt)
{
    struct mp_imgfmt_desc desc;

    if (!get_native_desc(mpfmt, &desc) &&
        !mp_imgfmt_get_desc_from_pixdesc(mpfmt, &desc))
        return (struct mp_imgfmt_desc){0};

    for (int p = 0; p < desc.num_planes; p++) {
        desc.xs[p] = (p == 1 || p == 2) ? desc.chroma_xs : 0;
        desc.ys[p] = (p == 1 || p == 2) ? desc.chroma_ys : 0;
    }

    bool is_ba = desc.num_planes > 0;
    for (int p = 0; p < desc.num_planes; p++)
        is_ba = !(desc.bpp[p] % 8u);

    if (is_ba)
        desc.flags |= MP_IMGFLAG_BYTE_ALIGNED;

    if (desc.flags & MP_IMGFLAG_HAS_COMPS) {
        if (desc.comps[3].size)
            desc.flags |= MP_IMGFLAG_ALPHA;

        // Assuming all colors are (CCC+[A]) or (C+[A]), the latter being gray.
        if (!desc.comps[1].size)
            desc.flags |= MP_IMGFLAG_GRAY;

        bool bb = true;
        for (int n = 0; n < MP_NUM_COMPONENTS; n++) {
            if (desc.comps[n].offset % 8u || desc.comps[n].size % 8u)
                bb = false;
        }
        if (bb)
            desc.flags |= MP_IMGFLAG_BYTES;
    }

    if ((desc.flags & (MP_IMGFLAG_YUV | MP_IMGFLAG_RGB))
        && (desc.flags & MP_IMGFLAG_HAS_COMPS)
        && (desc.flags & MP_IMGFLAG_BYTES)
        && ((desc.flags & MP_IMGFLAG_TYPE_MASK) == MP_IMGFLAG_TYPE_UINT))
    {
        int cnt = mp_imgfmt_desc_get_num_comps(&desc);
        bool same_depth = true;
        for (int p = 0; p < desc.num_planes; p++)
            same_depth &= desc.bpp[p] == desc.bpp[0];
        if (same_depth && cnt == desc.num_planes) {
            if (desc.flags & MP_IMGFLAG_YUV) {
                desc.flags |= MP_IMGFLAG_YUV_P;
            } else {
                desc.flags |= MP_IMGFLAG_RGB_P;
            }
        }
        if (cnt == 3 && desc.num_planes == 2 &&
            desc.bpp[1] == desc.bpp[0] * 2 &&
            (desc.flags & MP_IMGFLAG_YUV))
        {

            desc.flags |= MP_IMGFLAG_YUV_NV;
        }
    }

    return desc;
}

static bool validate_regular_imgfmt(const struct mp_regular_imgfmt *fmt)
{
    bool present[MP_NUM_COMPONENTS] = {0};
    int n_comp = 0;

    for (int n = 0; n < fmt->num_planes; n++) {
        const struct mp_regular_imgfmt_plane *plane = &fmt->planes[n];
        n_comp += plane->num_components;
        if (n_comp > MP_NUM_COMPONENTS)
            return false;
        if (!plane->num_components)
            return false; // no empty planes in between allowed

        bool pad_only = true;
        int chroma_luma = 0; // luma: 1, chroma: 2, both: 3
        for (int i = 0; i < plane->num_components; i++) {
            int comp = plane->components[i];
            if (comp > MP_NUM_COMPONENTS)
                return false;
            if (comp == 0)
                continue;
            pad_only = false;
            if (present[comp - 1])
                return false; // no duplicates
            present[comp - 1] = true;
            chroma_luma |= (comp == 2 || comp == 3) ? 2 : 1;
        }
        if (pad_only)
            return false; // no planes with only padding allowed
        if ((fmt->chroma_xs > 0 || fmt->chroma_ys > 0) && chroma_luma == 3)
            return false; // separate chroma/luma planes required
    }

    if (!(present[0] || present[3]) ||  // at least component 1 or alpha needed
        (present[1] && !present[0]) ||  // component 2 requires component 1
        (present[2] && !present[1]))    // component 3 requires component 2
        return false;

    return true;
}

static enum mp_csp get_forced_csp_from_flags(int flags)
{
    if (flags & MP_IMGFLAG_COLOR_XYZ)
        return MP_CSP_XYZ;

    if (flags & MP_IMGFLAG_COLOR_RGB)
        return MP_CSP_RGB;

    return MP_CSP_AUTO;
}

enum mp_csp mp_imgfmt_get_forced_csp(int imgfmt)
{
    return get_forced_csp_from_flags(mp_imgfmt_get_desc(imgfmt).flags);
}

static enum mp_component_type get_component_type_from_flags(int flags)
{
    if (flags & MP_IMGFLAG_TYPE_UINT)
        return MP_COMPONENT_TYPE_UINT;

    if (flags & MP_IMGFLAG_TYPE_FLOAT)
        return MP_COMPONENT_TYPE_FLOAT;

    return MP_COMPONENT_TYPE_UNKNOWN;
}

enum mp_component_type mp_imgfmt_get_component_type(int imgfmt)
{
    return get_component_type_from_flags(mp_imgfmt_get_desc(imgfmt).flags);
}

int mp_find_other_endian(int imgfmt)
{
    return pixfmt2imgfmt(av_pix_fmt_swap_endianness(imgfmt2pixfmt(imgfmt)));
}

bool mp_get_regular_imgfmt(struct mp_regular_imgfmt *dst, int imgfmt)
{
    struct mp_regular_imgfmt res = {0};

    struct mp_imgfmt_desc desc = mp_imgfmt_get_desc(imgfmt);
    if (!desc.num_planes)
        return false;
    res.num_planes = desc.num_planes;

    if (desc.endian_shift || !(desc.flags & MP_IMGFLAG_HAS_COMPS))
        return false;

    res.component_type = get_component_type_from_flags(desc.flags);
    if (!res.component_type)
        return false;

    struct mp_imgfmt_comp_desc *comp0 = &desc.comps[0];
    if (comp0->size < 1 || comp0->size > 64 || (comp0->size % 8u))
        return false;

    res.component_size = comp0->size / 8u;
    res.component_pad = comp0->pad;

    for (int n = 0; n < res.num_planes; n++) {
        if (desc.bpp[n] % comp0->size)
            return false;
        res.planes[n].num_components = desc.bpp[n] / comp0->size;
    }

    for (int n = 0; n < MP_NUM_COMPONENTS; n++) {
        struct mp_imgfmt_comp_desc *comp = &desc.comps[n];
        if (!comp->size)
            continue;

        struct mp_regular_imgfmt_plane *plane = &res.planes[comp->plane];

        res.num_planes = MPMAX(res.num_planes, comp->plane + 1);

        // We support uniform depth only.
        if (comp->size != comp0->size || comp->pad != comp0->pad)
            return false;

        // Size-aligned only.
        int pos = comp->offset / comp->size;
        if (comp->offset != pos * comp->size || pos >= MP_NUM_COMPONENTS)
            return false;

        if (plane->components[pos])
            return false;
        plane->components[pos] = n + 1;
    }

    res.chroma_xs = desc.chroma_xs;
    res.chroma_ys = desc.chroma_ys;

    res.forced_csp = get_forced_csp_from_flags(desc.flags);

    if (!validate_regular_imgfmt(&res))
        return false;

    *dst = res;
    return true;
}

static bool regular_imgfmt_equals(struct mp_regular_imgfmt *a,
                                  struct mp_regular_imgfmt *b)
{
    if (a->component_type != b->component_type ||
        a->component_size != b->component_size ||
        a->num_planes     != b->num_planes ||
        a->component_pad  != b->component_pad ||
        a->forced_csp     != b->forced_csp ||
        a->chroma_xs      != b->chroma_xs ||
        a->chroma_ys      != b->chroma_ys)
        return false;

    for (int n = 0; n < a->num_planes; n++) {
        int num_comps = a->planes[n].num_components;
        if (num_comps != b->planes[n].num_components)
            return false;
        for (int i = 0; i < num_comps; i++) {
            if (a->planes[n].components[i] != b->planes[n].components[i])
                return false;
        }
    }

    return true;
}

// Find a format that matches this one exactly.
int mp_find_regular_imgfmt(struct mp_regular_imgfmt *src)
{
    for (int n = IMGFMT_START + 1; n < IMGFMT_END; n++) {
        struct mp_regular_imgfmt f;
        if (mp_get_regular_imgfmt(&f, n) && regular_imgfmt_equals(src, &f))
            return n;
    }
    return 0;
}

// Compare the dst image formats, and return the one which can carry more data
// (e.g. higher depth, more color components, lower chroma subsampling, etc.),
// with respect to what is required to keep most of the src format.
// Returns the imgfmt, or 0 on error.
int mp_imgfmt_select_best(int dst1, int dst2, int src)
{
    enum AVPixelFormat dst1pxf = imgfmt2pixfmt(dst1);
    enum AVPixelFormat dst2pxf = imgfmt2pixfmt(dst2);
    enum AVPixelFormat srcpxf = imgfmt2pixfmt(src);
    enum AVPixelFormat dstlist[] = {dst1pxf, dst2pxf, AV_PIX_FMT_NONE};
    return pixfmt2imgfmt(avcodec_find_best_pix_fmt_of_list(dstlist, srcpxf, 1, 0));
}

// Same as mp_imgfmt_select_best(), but with a list of dst formats.
int mp_imgfmt_select_best_list(int *dst, int num_dst, int src)
{
    int best = 0;
    for (int n = 0; n < num_dst; n++)
        best = best ? mp_imgfmt_select_best(best, dst[n], src) : dst[n];
    return best;
}