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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /**
20  * @file
21  * misc image utilities
22  */
23 
24 #include "avassert.h"
25 #include "common.h"
26 #include "imgutils.h"
27 #include "imgutils_internal.h"
28 #include "internal.h"
29 #include "intreadwrite.h"
30 #include "log.h"
31 #include "mathematics.h"
32 #include "pixdesc.h"
33 #include "rational.h"
34 
av_image_fill_max_pixsteps(int max_pixsteps[4],int max_pixstep_comps[4],const AVPixFmtDescriptor * pixdesc)35 void av_image_fill_max_pixsteps(int max_pixsteps[4], int max_pixstep_comps[4],
36                                 const AVPixFmtDescriptor *pixdesc)
37 {
38     int i;
39     memset(max_pixsteps, 0, 4*sizeof(max_pixsteps[0]));
40     if (max_pixstep_comps)
41         memset(max_pixstep_comps, 0, 4*sizeof(max_pixstep_comps[0]));
42 
43     for (i = 0; i < 4; i++) {
44         const AVComponentDescriptor *comp = &(pixdesc->comp[i]);
45         if (comp->step > max_pixsteps[comp->plane]) {
46             max_pixsteps[comp->plane] = comp->step;
47             if (max_pixstep_comps)
48                 max_pixstep_comps[comp->plane] = i;
49         }
50     }
51 }
52 
53 static inline
image_get_linesize(int width,int plane,int max_step,int max_step_comp,const AVPixFmtDescriptor * desc)54 int image_get_linesize(int width, int plane,
55                        int max_step, int max_step_comp,
56                        const AVPixFmtDescriptor *desc)
57 {
58     int s, shifted_w, linesize;
59 
60     if (!desc)
61         return AVERROR(EINVAL);
62 
63     if (width < 0)
64         return AVERROR(EINVAL);
65     s = (max_step_comp == 1 || max_step_comp == 2) ? desc->log2_chroma_w : 0;
66     shifted_w = ((width + (1 << s) - 1)) >> s;
67     if (shifted_w && max_step > INT_MAX / shifted_w)
68         return AVERROR(EINVAL);
69     linesize = max_step * shifted_w;
70 
71     if (desc->flags & AV_PIX_FMT_FLAG_BITSTREAM)
72         linesize = (linesize + 7) >> 3;
73     return linesize;
74 }
75 
av_image_get_linesize(enum AVPixelFormat pix_fmt,int width,int plane)76 int av_image_get_linesize(enum AVPixelFormat pix_fmt, int width, int plane)
77 {
78     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
79     int max_step     [4];       /* max pixel step for each plane */
80     int max_step_comp[4];       /* the component for each plane which has the max pixel step */
81 
82     if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
83         return AVERROR(EINVAL);
84 
85     av_image_fill_max_pixsteps(max_step, max_step_comp, desc);
86     return image_get_linesize(width, plane, max_step[plane], max_step_comp[plane], desc);
87 }
88 
av_image_fill_linesizes(int linesizes[4],enum AVPixelFormat pix_fmt,int width)89 int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int width)
90 {
91     int i, ret;
92     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
93     int max_step     [4];       /* max pixel step for each plane */
94     int max_step_comp[4];       /* the component for each plane which has the max pixel step */
95 
96     memset(linesizes, 0, 4*sizeof(linesizes[0]));
97 
98     if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
99         return AVERROR(EINVAL);
100 
101     av_image_fill_max_pixsteps(max_step, max_step_comp, desc);
102     for (i = 0; i < 4; i++) {
103         if ((ret = image_get_linesize(width, i, max_step[i], max_step_comp[i], desc)) < 0)
104             return ret;
105         linesizes[i] = ret;
106     }
107 
108     return 0;
109 }
110 
av_image_fill_plane_sizes(size_t sizes[4],enum AVPixelFormat pix_fmt,int height,const ptrdiff_t linesizes[4])111 int av_image_fill_plane_sizes(size_t sizes[4], enum AVPixelFormat pix_fmt,
112                               int height, const ptrdiff_t linesizes[4])
113 {
114     int i, has_plane[4] = { 0 };
115 
116     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
117     memset(sizes    , 0, sizeof(sizes[0])*4);
118 
119     if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
120         return AVERROR(EINVAL);
121 
122     if (linesizes[0] > SIZE_MAX / height)
123         return AVERROR(EINVAL);
124     sizes[0] = linesizes[0] * (size_t)height;
125 
126     if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
127         sizes[1] = 256 * 4; /* palette is stored here as 256 32 bits words */
128         return 0;
129     }
130 
131     for (i = 0; i < 4; i++)
132         has_plane[desc->comp[i].plane] = 1;
133 
134     for (i = 1; i < 4 && has_plane[i]; i++) {
135         int h, s = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
136         h = (height + (1 << s) - 1) >> s;
137         if (linesizes[i] > SIZE_MAX / h)
138             return AVERROR(EINVAL);
139         sizes[i] = (size_t)h * linesizes[i];
140     }
141 
142     return 0;
143 }
144 
av_image_fill_pointers(uint8_t * data[4],enum AVPixelFormat pix_fmt,int height,uint8_t * ptr,const int linesizes[4])145 int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
146                            uint8_t *ptr, const int linesizes[4])
147 {
148     int i, ret;
149     ptrdiff_t linesizes1[4];
150     size_t sizes[4];
151 
152     memset(data     , 0, sizeof(data[0])*4);
153 
154     for (i = 0; i < 4; i++)
155         linesizes1[i] = linesizes[i];
156 
157     ret = av_image_fill_plane_sizes(sizes, pix_fmt, height, linesizes1);
158     if (ret < 0)
159         return ret;
160 
161     ret = 0;
162     for (i = 0; i < 4; i++) {
163         if (sizes[i] > INT_MAX - ret)
164             return AVERROR(EINVAL);
165         ret += sizes[i];
166     }
167 
168     if (!ptr)
169         return ret;
170 
171     data[0] = ptr;
172     for (i = 1; i < 4 && sizes[i]; i++)
173         data[i] = data[i - 1] + sizes[i - 1];
174 
175     return ret;
176 }
177 
avpriv_set_systematic_pal2(uint32_t pal[256],enum AVPixelFormat pix_fmt)178 int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
179 {
180     int i;
181 
182     for (i = 0; i < 256; i++) {
183         int r, g, b;
184 
185         switch (pix_fmt) {
186         case AV_PIX_FMT_RGB8:
187             r = (i>>5    )*36;
188             g = ((i>>2)&7)*36;
189             b = (i&3     )*85;
190             break;
191         case AV_PIX_FMT_BGR8:
192             b = (i>>6    )*85;
193             g = ((i>>3)&7)*36;
194             r = (i&7     )*36;
195             break;
196         case AV_PIX_FMT_RGB4_BYTE:
197             r = (i>>3    )*255;
198             g = ((i>>1)&3)*85;
199             b = (i&1     )*255;
200             break;
201         case AV_PIX_FMT_BGR4_BYTE:
202             b = (i>>3    )*255;
203             g = ((i>>1)&3)*85;
204             r = (i&1     )*255;
205             break;
206         case AV_PIX_FMT_GRAY8:
207             r = b = g = i;
208             break;
209         default:
210             return AVERROR(EINVAL);
211         }
212         pal[i] = b + (g << 8) + (r << 16) + (0xFFU << 24);
213     }
214 
215     return 0;
216 }
217 
av_image_alloc(uint8_t * pointers[4],int linesizes[4],int w,int h,enum AVPixelFormat pix_fmt,int align)218 int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
219                    int w, int h, enum AVPixelFormat pix_fmt, int align)
220 {
221     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
222     int i, ret;
223     ptrdiff_t linesizes1[4];
224     size_t total_size, sizes[4];
225     uint8_t *buf;
226 
227     if (!desc)
228         return AVERROR(EINVAL);
229 
230     if ((ret = av_image_check_size(w, h, 0, NULL)) < 0)
231         return ret;
232     if ((ret = av_image_fill_linesizes(linesizes, pix_fmt, align>7 ? FFALIGN(w, 8) : w)) < 0)
233         return ret;
234 
235     for (i = 0; i < 4; i++) {
236         linesizes[i] = FFALIGN(linesizes[i], align);
237         linesizes1[i] = linesizes[i];
238     }
239 
240     if ((ret = av_image_fill_plane_sizes(sizes, pix_fmt, h, linesizes1)) < 0)
241         return ret;
242     total_size = align;
243     for (i = 0; i < 4; i++) {
244         if (total_size > SIZE_MAX - sizes[i])
245             return AVERROR(EINVAL);
246         total_size += sizes[i];
247     }
248     buf = av_malloc(total_size);
249     if (!buf)
250         return AVERROR(ENOMEM);
251     if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, buf, linesizes)) < 0) {
252         av_free(buf);
253         return ret;
254     }
255     if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
256         avpriv_set_systematic_pal2((uint32_t*)pointers[1], pix_fmt);
257         if (align < 4) {
258             av_log(NULL, AV_LOG_ERROR, "Formats with a palette require a minimum alignment of 4\n");
259             av_free(buf);
260             return AVERROR(EINVAL);
261         }
262     }
263 
264     if (desc->flags & AV_PIX_FMT_FLAG_PAL && pointers[1] &&
265         pointers[1] - pointers[0] > linesizes[0] * h) {
266         /* zero-initialize the padding before the palette */
267         memset(pointers[0] + linesizes[0] * h, 0,
268                pointers[1] - pointers[0] - linesizes[0] * h);
269     }
270 
271     return ret;
272 }
273 
274 typedef struct ImgUtils {
275     const AVClass *class;
276     int   log_offset;
277     void *log_ctx;
278 } ImgUtils;
279 
280 static const AVClass imgutils_class = {
281     .class_name                = "IMGUTILS",
282     .item_name                 = av_default_item_name,
283     .option                    = NULL,
284     .version                   = LIBAVUTIL_VERSION_INT,
285     .log_level_offset_offset   = offsetof(ImgUtils, log_offset),
286     .parent_log_context_offset = offsetof(ImgUtils, log_ctx),
287 };
288 
av_image_check_size2(unsigned int w,unsigned int h,int64_t max_pixels,enum AVPixelFormat pix_fmt,int log_offset,void * log_ctx)289 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)
290 {
291     ImgUtils imgutils = {
292         .class      = &imgutils_class,
293         .log_offset = log_offset,
294         .log_ctx    = log_ctx,
295     };
296     int64_t stride = av_image_get_linesize(pix_fmt, w, 0);
297     if (stride <= 0)
298         stride = 8LL*w;
299     stride += 128*8;
300 
301     if ((int)w<=0 || (int)h<=0 || stride >= INT_MAX || stride*(uint64_t)(h+128) >= INT_MAX) {
302         av_log(&imgutils, AV_LOG_ERROR, "Picture size %ux%u is invalid\n", w, h);
303         return AVERROR(EINVAL);
304     }
305 
306     if (max_pixels < INT64_MAX) {
307         if (w*(int64_t)h > max_pixels) {
308             av_log(&imgutils, AV_LOG_ERROR,
309                     "Picture size %ux%u exceeds specified max pixel count %"PRId64", see the documentation if you wish to increase it\n",
310                     w, h, max_pixels);
311             return AVERROR(EINVAL);
312         }
313     }
314 
315     return 0;
316 }
317 
av_image_check_size(unsigned int w,unsigned int h,int log_offset,void * log_ctx)318 int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
319 {
320     return av_image_check_size2(w, h, INT64_MAX, AV_PIX_FMT_NONE, log_offset, log_ctx);
321 }
322 
av_image_check_sar(unsigned int w,unsigned int h,AVRational sar)323 int av_image_check_sar(unsigned int w, unsigned int h, AVRational sar)
324 {
325     int64_t scaled_dim;
326 
327     if (sar.den <= 0 || sar.num < 0)
328         return AVERROR(EINVAL);
329 
330     if (!sar.num || sar.num == sar.den)
331         return 0;
332 
333     if (sar.num < sar.den)
334         scaled_dim = av_rescale_rnd(w, sar.num, sar.den, AV_ROUND_ZERO);
335     else
336         scaled_dim = av_rescale_rnd(h, sar.den, sar.num, AV_ROUND_ZERO);
337 
338     if (scaled_dim > 0)
339         return 0;
340 
341     return AVERROR(EINVAL);
342 }
343 
image_copy_plane(uint8_t * dst,ptrdiff_t dst_linesize,const uint8_t * src,ptrdiff_t src_linesize,ptrdiff_t bytewidth,int height)344 static void image_copy_plane(uint8_t       *dst, ptrdiff_t dst_linesize,
345                              const uint8_t *src, ptrdiff_t src_linesize,
346                              ptrdiff_t bytewidth, int height)
347 {
348     if (!dst || !src)
349         return;
350     av_assert0(FFABS(src_linesize) >= bytewidth);
351     av_assert0(FFABS(dst_linesize) >= bytewidth);
352     for (;height > 0; height--) {
353         memcpy(dst, src, bytewidth);
354         dst += dst_linesize;
355         src += src_linesize;
356     }
357 }
358 
av_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)359 void av_image_copy_plane_uc_from(uint8_t *dst, ptrdiff_t dst_linesize,
360                                  const uint8_t *src, ptrdiff_t src_linesize,
361                                  ptrdiff_t bytewidth, int height)
362 {
363     int ret = -1;
364 
365 #if ARCH_X86
366     ret = ff_image_copy_plane_uc_from_x86(dst, dst_linesize, src, src_linesize,
367                                           bytewidth, height);
368 #endif
369 
370     if (ret < 0)
371         image_copy_plane(dst, dst_linesize, src, src_linesize, bytewidth, height);
372 }
373 
av_image_copy_plane(uint8_t * dst,int dst_linesize,const uint8_t * src,int src_linesize,int bytewidth,int height)374 void av_image_copy_plane(uint8_t       *dst, int dst_linesize,
375                          const uint8_t *src, int src_linesize,
376                          int bytewidth, int height)
377 {
378     image_copy_plane(dst, dst_linesize, src, src_linesize, bytewidth, height);
379 }
380 
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))381 static void image_copy(uint8_t *dst_data[4], const ptrdiff_t dst_linesizes[4],
382                        const uint8_t *src_data[4], const ptrdiff_t src_linesizes[4],
383                        enum AVPixelFormat pix_fmt, int width, int height,
384                        void (*copy_plane)(uint8_t *, ptrdiff_t, const uint8_t *,
385                                           ptrdiff_t, ptrdiff_t, int))
386 {
387     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
388 
389     if (!desc || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
390         return;
391 
392     if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
393         copy_plane(dst_data[0], dst_linesizes[0],
394                    src_data[0], src_linesizes[0],
395                    width, height);
396         /* copy the palette */
397         if ((desc->flags & AV_PIX_FMT_FLAG_PAL) || (dst_data[1] && src_data[1]))
398             memcpy(dst_data[1], src_data[1], 4*256);
399     } else {
400         int i, planes_nb = 0;
401 
402         for (i = 0; i < desc->nb_components; i++)
403             planes_nb = FFMAX(planes_nb, desc->comp[i].plane + 1);
404 
405         for (i = 0; i < planes_nb; i++) {
406             int h = height;
407             ptrdiff_t bwidth = av_image_get_linesize(pix_fmt, width, i);
408             if (bwidth < 0) {
409                 av_log(NULL, AV_LOG_ERROR, "av_image_get_linesize failed\n");
410                 return;
411             }
412             if (i == 1 || i == 2) {
413                 h = AV_CEIL_RSHIFT(height, desc->log2_chroma_h);
414             }
415             copy_plane(dst_data[i], dst_linesizes[i],
416                        src_data[i], src_linesizes[i],
417                        bwidth, h);
418         }
419     }
420 }
421 
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)422 void av_image_copy(uint8_t *dst_data[4], int dst_linesizes[4],
423                    const uint8_t *src_data[4], const int src_linesizes[4],
424                    enum AVPixelFormat pix_fmt, int width, int height)
425 {
426     ptrdiff_t dst_linesizes1[4], src_linesizes1[4];
427     int i;
428 
429     for (i = 0; i < 4; i++) {
430         dst_linesizes1[i] = dst_linesizes[i];
431         src_linesizes1[i] = src_linesizes[i];
432     }
433 
434     image_copy(dst_data, dst_linesizes1, src_data, src_linesizes1, pix_fmt,
435                width, height, image_copy_plane);
436 }
437 
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)438 void av_image_copy_uc_from(uint8_t *dst_data[4], const ptrdiff_t dst_linesizes[4],
439                            const uint8_t *src_data[4], const ptrdiff_t src_linesizes[4],
440                            enum AVPixelFormat pix_fmt, int width, int height)
441 {
442     image_copy(dst_data, dst_linesizes, src_data, src_linesizes, pix_fmt,
443                width, height, av_image_copy_plane_uc_from);
444 }
445 
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)446 int av_image_fill_arrays(uint8_t *dst_data[4], int dst_linesize[4],
447                          const uint8_t *src, enum AVPixelFormat pix_fmt,
448                          int width, int height, int align)
449 {
450     int ret, i;
451 
452     ret = av_image_check_size(width, height, 0, NULL);
453     if (ret < 0)
454         return ret;
455 
456     ret = av_image_fill_linesizes(dst_linesize, pix_fmt, width);
457     if (ret < 0)
458         return ret;
459 
460     for (i = 0; i < 4; i++)
461         dst_linesize[i] = FFALIGN(dst_linesize[i], align);
462 
463     return av_image_fill_pointers(dst_data, pix_fmt, height, (uint8_t *)src, dst_linesize);
464 }
465 
av_image_get_buffer_size(enum AVPixelFormat pix_fmt,int width,int height,int align)466 int av_image_get_buffer_size(enum AVPixelFormat pix_fmt,
467                              int width, int height, int align)
468 {
469     int ret, i;
470     int linesize[4];
471     ptrdiff_t aligned_linesize[4];
472     size_t sizes[4];
473     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
474     if (!desc)
475         return AVERROR(EINVAL);
476 
477     ret = av_image_check_size(width, height, 0, NULL);
478     if (ret < 0)
479         return ret;
480 
481     ret = av_image_fill_linesizes(linesize, pix_fmt, width);
482     if (ret < 0)
483         return ret;
484 
485     for (i = 0; i < 4; i++)
486         aligned_linesize[i] = FFALIGN(linesize[i], align);
487 
488     ret = av_image_fill_plane_sizes(sizes, pix_fmt, height, aligned_linesize);
489     if (ret < 0)
490         return ret;
491 
492     ret = 0;
493     for (i = 0; i < 4; i++) {
494         if (sizes[i] > INT_MAX - ret)
495             return AVERROR(EINVAL);
496         ret += sizes[i];
497     }
498     return ret;
499 }
500 
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)501 int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
502                             const uint8_t * const src_data[4],
503                             const int src_linesize[4],
504                             enum AVPixelFormat pix_fmt,
505                             int width, int height, int align)
506 {
507     int i, j, nb_planes = 0, linesize[4];
508     int size = av_image_get_buffer_size(pix_fmt, width, height, align);
509     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
510     int ret;
511 
512     if (size > dst_size || size < 0 || !desc)
513         return AVERROR(EINVAL);
514 
515     for (i = 0; i < desc->nb_components; i++)
516         nb_planes = FFMAX(desc->comp[i].plane, nb_planes);
517 
518     nb_planes++;
519 
520     ret = av_image_fill_linesizes(linesize, pix_fmt, width);
521     av_assert0(ret >= 0); // was checked previously
522 
523     for (i = 0; i < nb_planes; i++) {
524         int h, shift = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
525         const uint8_t *src = src_data[i];
526         h = (height + (1 << shift) - 1) >> shift;
527 
528         for (j = 0; j < h; j++) {
529             memcpy(dst, src, linesize[i]);
530             dst += FFALIGN(linesize[i], align);
531             src += src_linesize[i];
532         }
533     }
534 
535     if (desc->flags & AV_PIX_FMT_FLAG_PAL) {
536         uint32_t *d32 = (uint32_t *)dst;
537 
538         for (i = 0; i<256; i++)
539             AV_WL32(d32 + i, AV_RN32(src_data[1] + 4*i));
540     }
541 
542     return size;
543 }
544 
545 // Fill dst[0..dst_size] with the bytes in clear[0..clear_size]. The clear
546 // bytes are repeated until dst_size is reached. If dst_size is unaligned (i.e.
547 // dst_size%clear_size!=0), the remaining data will be filled with the beginning
548 // of the clear data only.
memset_bytes(uint8_t * dst,size_t dst_size,uint8_t * clear,size_t clear_size)549 static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear,
550                          size_t clear_size)
551 {
552     int same = 1;
553     int i;
554 
555     if (!clear_size)
556         return;
557 
558     // Reduce to memset() if possible.
559     for (i = 0; i < clear_size; i++) {
560         if (clear[i] != clear[0]) {
561             same = 0;
562             break;
563         }
564     }
565     if (same)
566         clear_size = 1;
567 
568     if (clear_size == 1) {
569         memset(dst, clear[0], dst_size);
570     } else {
571         if (clear_size > dst_size)
572             clear_size = dst_size;
573         memcpy(dst, clear, clear_size);
574         av_memcpy_backptr(dst + clear_size, clear_size, dst_size - clear_size);
575     }
576 }
577 
578 // Maximum size in bytes of a plane element (usually a pixel, or multiple pixels
579 // if it's a subsampled packed format).
580 #define MAX_BLOCK_SIZE 32
581 
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)582 int av_image_fill_black(uint8_t *dst_data[4], const ptrdiff_t dst_linesize[4],
583                         enum AVPixelFormat pix_fmt, enum AVColorRange range,
584                         int width, int height)
585 {
586     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
587     int nb_planes = av_pix_fmt_count_planes(pix_fmt);
588     // A pixel or a group of pixels on each plane, with a value that represents black.
589     // Consider e.g. AV_PIX_FMT_UYVY422 for non-trivial cases.
590     uint8_t clear_block[4][MAX_BLOCK_SIZE] = {{0}}; // clear padding with 0
591     int clear_block_size[4] = {0};
592     ptrdiff_t plane_line_bytes[4] = {0};
593     int rgb, limited;
594     int plane, c;
595 
596     if (!desc || nb_planes < 1 || nb_planes > 4 || desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
597         return AVERROR(EINVAL);
598 
599     rgb = !!(desc->flags & AV_PIX_FMT_FLAG_RGB);
600     limited = !rgb && range != AVCOL_RANGE_JPEG;
601 
602     if (desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) {
603         ptrdiff_t bytewidth = av_image_get_linesize(pix_fmt, width, 0);
604         uint8_t *data;
605         int mono = pix_fmt == AV_PIX_FMT_MONOWHITE || pix_fmt == AV_PIX_FMT_MONOBLACK;
606         int fill = pix_fmt == AV_PIX_FMT_MONOWHITE ? 0xFF : 0;
607         if (nb_planes != 1 || !(rgb || mono) || bytewidth < 1)
608             return AVERROR(EINVAL);
609 
610         if (!dst_data)
611             return 0;
612 
613         data = dst_data[0];
614 
615         // (Bitstream + alpha will be handled incorrectly - it'll remain transparent.)
616         for (;height > 0; height--) {
617             memset(data, fill, bytewidth);
618             data += dst_linesize[0];
619         }
620         return 0;
621     }
622 
623     for (c = 0; c < desc->nb_components; c++) {
624         const AVComponentDescriptor comp = desc->comp[c];
625 
626         // We try to operate on entire non-subsampled pixel groups (for
627         // AV_PIX_FMT_UYVY422 this would mean two consecutive pixels).
628         clear_block_size[comp.plane] = FFMAX(clear_block_size[comp.plane], comp.step);
629 
630         if (clear_block_size[comp.plane] > MAX_BLOCK_SIZE)
631             return AVERROR(EINVAL);
632     }
633 
634     // Create a byte array for clearing 1 pixel (sometimes several pixels).
635     for (c = 0; c < desc->nb_components; c++) {
636         const AVComponentDescriptor comp = desc->comp[c];
637         // (Multiple pixels happen e.g. with AV_PIX_FMT_UYVY422.)
638         int w = clear_block_size[comp.plane] / comp.step;
639         uint8_t *c_data[4];
640         const int c_linesize[4] = {0};
641         uint16_t src_array[MAX_BLOCK_SIZE];
642         uint16_t src = 0;
643         int x;
644 
645         if (comp.depth > 16)
646             return AVERROR(EINVAL);
647         if (!rgb && comp.depth < 8)
648             return AVERROR(EINVAL);
649         if (w < 1)
650             return AVERROR(EINVAL);
651 
652         if (c == 0 && limited) {
653             src = 16 << (comp.depth - 8);
654         } else if ((c == 1 || c == 2) && !rgb) {
655             src = 128 << (comp.depth - 8);
656         } else if (c == 3) {
657             // (Assume even limited YUV uses full range alpha.)
658             src = (1 << comp.depth) - 1;
659         }
660 
661         for (x = 0; x < w; x++)
662             src_array[x] = src;
663 
664         for (x = 0; x < 4; x++)
665             c_data[x] = &clear_block[x][0];
666 
667         av_write_image_line(src_array, c_data, c_linesize, desc, 0, 0, c, w);
668     }
669 
670     for (plane = 0; plane < nb_planes; plane++) {
671         plane_line_bytes[plane] = av_image_get_linesize(pix_fmt, width, plane);
672         if (plane_line_bytes[plane] < 0)
673             return AVERROR(EINVAL);
674     }
675 
676     if (!dst_data)
677         return 0;
678 
679     for (plane = 0; plane < nb_planes; plane++) {
680         size_t bytewidth = plane_line_bytes[plane];
681         uint8_t *data = dst_data[plane];
682         int chroma_div = plane == 1 || plane == 2 ? desc->log2_chroma_h : 0;
683         int plane_h = ((height + ( 1 << chroma_div) - 1)) >> chroma_div;
684 
685         for (; plane_h > 0; plane_h--) {
686             memset_bytes(data, bytewidth, &clear_block[plane][0], clear_block_size[plane]);
687             data += dst_linesize[plane];
688         }
689     }
690 
691     return 0;
692 }
693