aboutsummaryrefslogtreecommitdiffstats
path: root/libavutil/imgutils.c
blob: 4938a7ef6767f5a7e7e0a103b2435e0a32e3a76b (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
/*
 * 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
 * misc image utilities
 */

#include "avassert.h"
#include "common.h"
#include "imgutils.h"
#include "imgutils_internal.h"
#include "internal.h"
#include "intreadwrite.h"
#include "log.h"
#include "mathematics.h"
#include "pixdesc.h"
#include "rational.h"

void av_image_fill_max_pixsteps(int max_pixsteps[4], int max_pixstep_comps[4],
                                const AVPixFmtDescriptor *pixdesc)
{
    int i;
    memset(max_pixsteps, 0, 4*sizeof(max_pixsteps[0]));
    if (max_pixstep_comps)
        memset(max_pixstep_comps, 0, 4*sizeof(max_pixstep_comps[0]));

    for (i = 0; i < 4; i++) {
        const AVComponentDescriptor *comp = &(pixdesc->comp[i]);
        if (comp->step > max_pixsteps[comp->plane]) {
            max_pixsteps[comp->plane] = comp->step;
            if (max_pixstep_comps)
                max_pixstep_comps[comp->plane] = i;
        }
    }
}

static inline
int image_get_linesize(int width, int plane,
                       int max_step, int max_step_comp,
                       const AVPixFmtDescriptor *desc)
{
    int s, shifted_w, linesize;

    if (!desc)
        return AVERROR(EINVAL);

    if (width < 0)
        return AVERROR(EINVAL);
    s = (max_step_comp == 1 || max_step_comp == 2) ? desc->log2_chroma_w : 0;
    shifted_w = ((width + (1 << s) - 1)) >> s;
    if (shifted_w && max_step > INT_MAX / shifted_w)
        return AVERROR(EINVAL);
    linesize = max_step * shifted_w;

    if (desc->flags & AV_PIX_FMT_FLAG_BITSTREAM)
        linesize = (linesize + 7) >> 3;
    return linesize;
}

int av_image_get_linesize(enum AVPixelFormat pix_fmt, int width, int plane)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    int max_step     [4];       /* max pixel step for each plane */
    int max_step_comp[4];       /* the component for each plane which has the max pixel step */

    if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
        return AVERROR(EINVAL);

    av_image_fill_max_pixsteps(max_step, max_step_comp, desc);
    return image_get_linesize(width, plane, max_step[plane], max_step_comp[plane], desc);
}

int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int width)
{
    int i, ret;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    int max_step     [4];       /* max pixel step for each plane */
    int max_step_comp[4];       /* the component for each plane which has the max pixel step */

    memset(linesizes, 0, 4*sizeof(linesizes[0]));

    if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
        return AVERROR(EINVAL);

    av_image_fill_max_pixsteps(max_step, max_step_comp, desc);
    for (i = 0; i < 4; i++) {
        if ((ret = image_get_linesize(width, i, max_step[i], max_step_comp[i], desc)) < 0)
            return ret;
        linesizes[i] = ret;
    }

    return 0;
}

int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
                           uint8_t *ptr, const int linesizes[4])
{
    int i, total_size, size[4] = { 0 }, has_plane[4] = { 0 };

    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    memset(data     , 0, sizeof(data[0])*4);

    if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
        return AVERROR(EINVAL);

    data[0] = ptr;
    if (linesizes[0] > (INT_MAX - 1024) / height)
        return AVERROR(EINVAL);
    size[0] = linesizes[0] * height;

    if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
        desc->flags & FF_PSEUDOPAL) {
        data[1] = ptr + size[0]; /* palette is stored here as 256 32 bits words */
        return size[0] + 256 * 4;
    }

    for (i = 0; i < 4; i++)
        has_plane[desc->comp[i].plane] = 1;

    total_size = size[0];
    for (i = 1; i < 4 && has_plane[i]; i++) {
        int h, s = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
        data[i] = data[i-1] + size[i-1];
        h = (height + (1 << s) - 1) >> s;
        if (linesizes[i] > INT_MAX / h)
            return AVERROR(EINVAL);
        size[i] = h * linesizes[i];
        if (total_size > INT_MAX - size[i])
            return AVERROR(EINVAL);
        total_size += size[i];
    }

    return total_size;
}

int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
{
    int i;

    for (i = 0; i < 256; i++) {
        int r, g, b;

        switch (pix_fmt) {
        case AV_PIX_FMT_RGB8:
            r = (i>>5    )*36;
            g = ((i>>2)&7)*36;
            b = (i&3     )*85;
            break;
        case AV_PIX_FMT_BGR8:
            b = (i>>6    )*85;
            g = ((i>>3)&7)*36;
            r = (i&7     )*36;
            break;
        case AV_PIX_FMT_RGB4_BYTE:
            r = (i>>3    )*255;
            g = ((i>>1)&3)*85;
            b = (i&1     )*255;
            break;
        case AV_PIX_FMT_BGR4_BYTE:
            b = (i>>3    )*255;
            g = ((i>>1)&3)*85;
            r = (i&1     )*255;
            break;
        case AV_PIX_FMT_GRAY8:
            r = b = g = i;
            break;
        default:
            return AVERROR(EINVAL);
        }
        pal[i] = b + (g << 8) + (r << 16) + (0xFFU << 24);
    }

    return 0;
}

int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
                   int w, int h, enum AVPixelFormat pix_fmt, int align)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    int i, ret;
    uint8_t *buf;

    if (!desc)
        return AVERROR(EINVAL);

    if ((ret = av_image_check_size(w, h, 0, NULL)) < 0)
        return ret;
    if ((ret = av_image_fill_linesizes(linesizes, pix_fmt, align>7 ? FFALIGN(w, 8) : w)) < 0)
        return ret;

    for (i = 0; i < 4; i++)
        linesizes[i] = FFALIGN(linesizes[i], align);

    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, NULL, linesizes)) < 0)
        return ret;
    buf = av_malloc(ret + align);
    if (!buf)
        return AVERROR(ENOMEM);
    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, buf, linesizes)) < 0) {
        av_free(buf);
        return ret;
    }
    if (desc->flags & AV_PIX_FMT_FLAG_PAL || (desc->flags & FF_PSEUDOPAL && pointers[1])) {
        avpriv_set_systematic_pal2((uint32_t*)pointers[1], pix_fmt);
        if (align < 4) {
            av_log(NULL, AV_LOG_ERROR, "Formats with a palette require a minimum alignment of 4\n");
            return AVERROR(EINVAL);
        }
    }

    if ((desc->flags & AV_PIX_FMT_FLAG_PAL ||
         desc->flags & FF_PSEUDOPAL) && pointers[1] &&
        pointers[1] - pointers[0] > linesizes[0] * h) {
        /* zero-initialize the padding before the palette */
        memset(pointers[0] + linesizes[0] * h, 0,
               pointers[1] - pointers[0] - linesizes[0] * h);
    }

    return ret;
}

typedef struct ImgUtils {
    const AVClass *class;
    int   log_offset;
    void *log_ctx;
} ImgUtils;

static const AVClass imgutils_class = {
    .class_name                = "IMGUTILS",
    .item_name                 = av_default_item_name,
    .option                    = NULL,
    .version                   = LIBAVUTIL_VERSION_INT,
    .log_level_offset_offset   = offsetof(ImgUtils, log_offset),
    .parent_log_context_offset = offsetof(ImgUtils, log_ctx),
};

int av_image_check_size2(unsigned int w, unsigned int h, int64_t max_pixels, enum AVPixelFormat pix_fmt, int log_offset, void *log_ctx)
{
    ImgUtils imgutils = {
        .class      = &imgutils_class,
        .log_offset = log_offset,
        .log_ctx    = log_ctx,
    };
    int64_t stride = av_image_get_linesize(pix_fmt, w, 0);
    if (stride <= 0)
        stride = 8LL*w;
    stride += 128*8;

    if ((int)w<=0 || (int)h<=0 || stride >= INT_MAX || stride*(uint64_t)(h+128) >= INT_MAX) {
        av_log(&imgutils, AV_LOG_ERROR, "Picture size %ux%u is invalid\n", w, h);
        return AVERROR(EINVAL);
    }

    if (max_pixels < INT64_MAX) {
        if (w*(int64_t)h > max_pixels) {
            av_log(&imgutils, AV_LOG_ERROR,
                    "Picture size %ux%u exceeds specified max pixel count %"PRId64", see the documentation if you wish to increase it\n",
                    w, h, max_pixels);
            return AVERROR(EINVAL);
        }
    }

    return 0;
}

int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
{
    return av_image_check_size2(w, h, INT64_MAX, AV_PIX_FMT_NONE, log_offset, log_ctx);
}

int av_image_check_sar(unsigned int w, unsigned int h, AVRational sar)
{
    int64_t scaled_dim;

    if (sar.den <= 0 || sar.num < 0)
        return AVERROR(EINVAL);

    if (!sar.num || sar.num == sar.den)
        return 0;

    if (sar.num < sar.den)
        scaled_dim = av_rescale_rnd(w, sar.num, sar.den, AV_ROUND_ZERO);
    else
        scaled_dim = av_rescale_rnd(h, sar.den, sar.num, AV_ROUND_ZERO);

    if (scaled_dim > 0)
        return 0;

    return AVERROR(EINVAL);
}

static void image_copy_plane(uint8_t       *dst, ptrdiff_t dst_linesize,
                             const uint8_t *src, ptrdiff_t src_linesize,
                             ptrdiff_t bytewidth, int height)
{
    if (!dst || !src)
        return;
    av_assert0(abs(src_linesize) >= bytewidth);
    av_assert0(abs(dst_linesize) >= bytewidth);
    for (;height > 0; height--) {
        memcpy(dst, src, bytewidth);
        dst += dst_linesize;
        src += src_linesize;
    }
}

static void image_copy_plane_uc_from(uint8_t       *dst, ptrdiff_t dst_linesize,
                                     const uint8_t *src, ptrdiff_t src_linesize,
                                     ptrdiff_t bytewidth, int height)
{
    int ret = -1;

#if ARCH_X86
    ret = ff_image_copy_plane_uc_from_x86(dst, dst_linesize, src, src_linesize,
                                          bytewidth, height);
#endif

    if (ret < 0)
        image_copy_plane(dst, dst_linesize, src, src_linesize, bytewidth, height);
}

void av_image_copy_plane(uint8_t       *dst, int dst_linesize,
                         const uint8_t *src, int src_linesize,
                         int bytewidth, int height)
{
    image_copy_plane(dst, dst_linesize, src, src_linesize, bytewidth, height);
}

static void image_copy(uint8_t *dst_data[4], const ptrdiff_t dst_linesizes[4],
                       const uint8_t *src_data[4], const ptrdiff_t src_linesizes[4],
                       enum AVPixelFormat pix_fmt, int width, int height,
                       void (*copy_plane)(uint8_t *, ptrdiff_t, const uint8_t *,
                                          ptrdiff_t, ptrdiff_t, int))
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);

    if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
        return;

    if (desc->flags & AV_PIX_FMT_FLAG_PAL ||
        desc->flags & FF_PSEUDOPAL) {
        copy_plane(dst_data[0], dst_linesizes[0],
                   src_data[0], src_linesizes[0],
                   width, height);
        /* copy the palette */
        if ((desc->flags & AV_PIX_FMT_FLAG_PAL) || (dst_data[1] && src_data[1]))
            memcpy(dst_data[1], src_data[1], 4*256);
    } else {
        int i, planes_nb = 0;

        for (i = 0; i < desc->nb_components; i++)
            planes_nb = FFMAX(planes_nb, desc->comp[i].plane + 1);

        for (i = 0; i < planes_nb; i++) {
            int h = height;
            ptrdiff_t bwidth = av_image_get_linesize(pix_fmt, width, i);
            if (bwidth < 0) {
                av_log(NULL, AV_LOG_ERROR, "av_image_get_linesize failed\n");
                return;
            }
            if (i == 1 || i == 2) {
                h = AV_CEIL_RSHIFT(height, desc->log2_chroma_h);
            }
            copy_plane(dst_data[i], dst_linesizes[i],
                       src_data[i], src_linesizes[i],
                       bwidth, h);
        }
    }
}

void av_image_copy(uint8_t *dst_data[4], int dst_linesizes[4],
                   const uint8_t *src_data[4], const int src_linesizes[4],
                   enum AVPixelFormat pix_fmt, int width, int height)
{
    ptrdiff_t dst_linesizes1[4], src_linesizes1[4];
    int i;

    for (i = 0; i < 4; i++) {
        dst_linesizes1[i] = dst_linesizes[i];
        src_linesizes1[i] = src_linesizes[i];
    }

    image_copy(dst_data, dst_linesizes1, src_data, src_linesizes1, pix_fmt,
               width, height, image_copy_plane);
}

void av_image_copy_uc_from(uint8_t *dst_data[4], const ptrdiff_t dst_linesizes[4],
                           const uint8_t *src_data[4], const ptrdiff_t src_linesizes[4],
                           enum AVPixelFormat pix_fmt, int width, int height)
{
    image_copy(dst_data, dst_linesizes, src_data, src_linesizes, pix_fmt,
               width, height, image_copy_plane_uc_from);
}

int av_image_fill_arrays(uint8_t *dst_data[4], int dst_linesize[4],
                         const uint8_t *src, enum AVPixelFormat pix_fmt,
                         int width, int height, int align)
{
    int ret, i;

    ret = av_image_check_size(width, height, 0, NULL);
    if (ret < 0)
        return ret;

    ret = av_image_fill_linesizes(dst_linesize, pix_fmt, width);
    if (ret < 0)
        return ret;

    for (i = 0; i < 4; i++)
        dst_linesize[i] = FFALIGN(dst_linesize[i], align);

    return av_image_fill_pointers(dst_data, pix_fmt, height, (uint8_t *)src, dst_linesize);
}

int av_image_get_buffer_size(enum AVPixelFormat pix_fmt,
                             int width, int height, int align)
{
    uint8_t *data[4];
    int linesize[4];
    int ret;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    if (!desc)
        return AVERROR(EINVAL);

    ret = av_image_check_size(width, height, 0, NULL);
    if (ret < 0)
        return ret;

    // do not include palette for these pseudo-paletted formats
    if (desc->flags & FF_PSEUDOPAL)
        return FFALIGN(width, align) * height;

    return av_image_fill_arrays(data, linesize, NULL, pix_fmt,
                                width, height, align);
}

int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
                            const uint8_t * const src_data[4],
                            const int src_linesize[4],
                            enum AVPixelFormat pix_fmt,
                            int width, int height, int align)
{
    int i, j, nb_planes = 0, linesize[4];
    int size = av_image_get_buffer_size(pix_fmt, width, height, align);
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    int ret;

    if (size > dst_size || size < 0 || !desc)
        return AVERROR(EINVAL);

    for (i = 0; i < desc->nb_components; i++)
        nb_planes = FFMAX(desc->comp[i].plane, nb_planes);

    nb_planes++;

    ret = av_image_fill_linesizes(linesize, pix_fmt, width);
    av_assert0(ret >= 0); // was checked previously

    for (i = 0; i < nb_planes; i++) {
        int h, shift = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
        const uint8_t *src = src_data[i];
        h = (height + (1 << shift) - 1) >> shift;

        for (j = 0; j < h; j++) {
            memcpy(dst, src, linesize[i]);
            dst += FFALIGN(linesize[i], align);
            src += src_linesize[i];
        }
    }

    if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
        uint32_t *d32 = (uint32_t *)dst;

        for (i = 0; i<256; i++)
            AV_WL32(d32 + i, AV_RN32(src_data[1] + 4*i));
    }

    return size;
}

// Fill dst[0..dst_size] with the bytes in clear[0..clear_size]. The clear
// bytes are repeated until dst_size is reached. If dst_size is unaligned (i.e.
// dst_size%clear_size!=0), the remaining data will be filled with the beginning
// of the clear data only.
static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear,
                         size_t clear_size)
{
    size_t pos = 0;
    int same = 1;
    int i;

    if (!clear_size)
        return;

    // Reduce to memset() if possible.
    for (i = 0; i < clear_size; i++) {
        if (clear[i] != clear[0]) {
            same = 0;
            break;
        }
    }
    if (same)
        clear_size = 1;

    if (clear_size == 1) {
        memset(dst, clear[0], dst_size);
        dst_size = 0;
    } else if (clear_size == 2) {
        uint16_t val = AV_RN16(clear);
        for (; dst_size >= 2; dst_size -= 2) {
            AV_WN16(dst, val);
            dst += 2;
        }
    } else if (clear_size == 4) {
        uint32_t val = AV_RN32(clear);
        for (; dst_size >= 4; dst_size -= 4) {
            AV_WN32(dst, val);
            dst += 4;
        }
    } else if (clear_size == 8) {
        uint32_t val = AV_RN64(clear);
        for (; dst_size >= 8; dst_size -= 8) {
            AV_WN64(dst, val);
            dst += 8;
        }
    }

    for (; dst_size; dst_size--)
        *dst++ = clear[pos++ % clear_size];
}

// Maximum size in bytes of a plane element (usually a pixel, or multiple pixels
// if it's a subsampled packed format).
#define MAX_BLOCK_SIZE 32

int av_image_fill_black(uint8_t *dst_data[4], const ptrdiff_t dst_linesize[4],
                        enum AVPixelFormat pix_fmt, enum AVColorRange range,
                        int width, int height)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    int nb_planes = av_pix_fmt_count_planes(pix_fmt);
    // A pixel or a group of pixels on each plane, with a value that represents black.
    // Consider e.g. AV_PIX_FMT_UYVY422 for non-trivial cases.
    uint8_t clear_block[4][MAX_BLOCK_SIZE] = {{0}}; // clear padding with 0
    int clear_block_size[4] = {0};
    ptrdiff_t plane_line_bytes[4] = {0};
    int rgb, limited;
    int plane, c;

    if (!desc || nb_planes < 1 || nb_planes > 4 || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
        return AVERROR(EINVAL);

    rgb = !!(desc->flags & AV_PIX_FMT_FLAG_RGB);
    limited = !rgb && range != AVCOL_RANGE_JPEG;

    if (desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) {
        ptrdiff_t bytewidth = av_image_get_linesize(pix_fmt, width, 0);
        uint8_t *data;
        int mono = pix_fmt == AV_PIX_FMT_MONOWHITE || pix_fmt == AV_PIX_FMT_MONOBLACK;
        int fill = pix_fmt == AV_PIX_FMT_MONOWHITE ? 0xFF : 0;
        if (nb_planes != 1 || !(rgb || mono) || bytewidth < 1)
            return AVERROR(EINVAL);

        if (!dst_data)
            return 0;

        data = dst_data[0];

        // (Bitstream + alpha will be handled incorrectly - it'll remain transparent.)
        for (;height > 0; height--) {
            memset(data, fill, bytewidth);
            data += dst_linesize[0];
        }
        return 0;
    }

    for (c = 0; c < desc->nb_components; c++) {
        const AVComponentDescriptor comp = desc->comp[c];

        // We try to operate on entire non-subsampled pixel groups (for
        // AV_PIX_FMT_UYVY422 this would mean two consecutive pixels).
        clear_block_size[comp.plane] = FFMAX(clear_block_size[comp.plane], comp.step);

        if (clear_block_size[comp.plane] > MAX_BLOCK_SIZE)
            return AVERROR(EINVAL);
    }

    // Create a byte array for clearing 1 pixel (sometimes several pixels).
    for (c = 0; c < desc->nb_components; c++) {
        const AVComponentDescriptor comp = desc->comp[c];
        // (Multiple pixels happen e.g. with AV_PIX_FMT_UYVY422.)
        int w = clear_block_size[comp.plane] / comp.step;
        uint8_t *c_data[4];
        const int c_linesize[4] = {0};
        uint16_t src_array[MAX_BLOCK_SIZE];
        uint16_t src = 0;
        int x;

        if (comp.depth > 16)
            return AVERROR(EINVAL);
        if (!rgb && comp.depth < 8)
            return AVERROR(EINVAL);
        if (w < 1)
            return AVERROR(EINVAL);

        if (c == 0 && limited) {
            src = 16 << (comp.depth - 8);
        } else if ((c == 1 || c == 2) && !rgb) {
            src = 128 << (comp.depth - 8);
        } else if (c == 3) {
            // (Assume even limited YUV uses full range alpha.)
            src = (1 << comp.depth) - 1;
        }

        for (x = 0; x < w; x++)
            src_array[x] = src;

        for (x = 0; x < 4; x++)
            c_data[x] = &clear_block[x][0];

        av_write_image_line(src_array, c_data, c_linesize, desc, 0, 0, c, w);
    }

    for (plane = 0; plane < nb_planes; plane++) {
        plane_line_bytes[plane] = av_image_get_linesize(pix_fmt, width, plane);
        if (plane_line_bytes[plane] < 0)
            return AVERROR(EINVAL);
    }

    if (!dst_data)
        return 0;

    for (plane = 0; plane < nb_planes; plane++) {
        size_t bytewidth = plane_line_bytes[plane];
        uint8_t *data = dst_data[plane];
        int chroma_div = plane == 1 || plane == 2 ? desc->log2_chroma_h : 0;
        int plane_h = ((height + ( 1 << chroma_div) - 1)) >> chroma_div;

        for (; plane_h > 0; plane_h--) {
            memset_bytes(data, bytewidth, &clear_block[plane][0], clear_block_size[plane]);
            data += dst_linesize[plane];
        }
    }

    return 0;
}