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1 /*
2  * PNG image format
3  * Copyright (c) 2003 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avcodec.h"
23 #include "codec_internal.h"
24 #include "encode.h"
25 #include "bytestream.h"
26 #include "lossless_videoencdsp.h"
27 #include "png.h"
28 #include "apng.h"
29 #include "zlib_wrapper.h"
30 
31 #include "libavutil/avassert.h"
32 #include "libavutil/crc.h"
33 #include "libavutil/libm.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/color_utils.h"
36 #include "libavutil/stereo3d.h"
37 
38 #include <zlib.h>
39 
40 #define IOBUF_SIZE 4096
41 
42 typedef struct APNGFctlChunk {
43     uint32_t sequence_number;
44     uint32_t width, height;
45     uint32_t x_offset, y_offset;
46     uint16_t delay_num, delay_den;
47     uint8_t dispose_op, blend_op;
48 } APNGFctlChunk;
49 
50 typedef struct PNGEncContext {
51     AVClass *class;
52     LLVidEncDSPContext llvidencdsp;
53 
54     uint8_t *bytestream;
55     uint8_t *bytestream_start;
56     uint8_t *bytestream_end;
57 
58     int filter_type;
59 
60     FFZStream zstream;
61     uint8_t buf[IOBUF_SIZE];
62     int dpi;                     ///< Physical pixel density, in dots per inch, if set
63     int dpm;                     ///< Physical pixel density, in dots per meter, if set
64 
65     int is_progressive;
66     int bit_depth;
67     int color_type;
68     int bits_per_pixel;
69 
70     // APNG
71     uint32_t palette_checksum;   // Used to ensure a single unique palette
72     uint32_t sequence_number;
73     int extra_data_updated;
74     uint8_t *extra_data;
75     int extra_data_size;
76 
77     AVFrame *prev_frame;
78     AVFrame *last_frame;
79     APNGFctlChunk last_frame_fctl;
80     uint8_t *last_frame_packet;
81     size_t last_frame_packet_size;
82 } PNGEncContext;
83 
png_get_interlaced_row(uint8_t * dst,int row_size,int bits_per_pixel,int pass,const uint8_t * src,int width)84 static void png_get_interlaced_row(uint8_t *dst, int row_size,
85                                    int bits_per_pixel, int pass,
86                                    const uint8_t *src, int width)
87 {
88     int x, mask, dst_x, j, b, bpp;
89     uint8_t *d;
90     const uint8_t *s;
91     static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
92 
93     mask = masks[pass];
94     switch (bits_per_pixel) {
95     case 1:
96         memset(dst, 0, row_size);
97         dst_x = 0;
98         for (x = 0; x < width; x++) {
99             j = (x & 7);
100             if ((mask << j) & 0x80) {
101                 b = (src[x >> 3] >> (7 - j)) & 1;
102                 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
103                 dst_x++;
104             }
105         }
106         break;
107     default:
108         bpp = bits_per_pixel >> 3;
109         d = dst;
110         s = src;
111         for (x = 0; x < width; x++) {
112             j = x & 7;
113             if ((mask << j) & 0x80) {
114                 memcpy(d, s, bpp);
115                 d += bpp;
116             }
117             s += bpp;
118         }
119         break;
120     }
121 }
122 
sub_png_paeth_prediction(uint8_t * dst,uint8_t * src,uint8_t * top,int w,int bpp)123 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top,
124                                      int w, int bpp)
125 {
126     int i;
127     for (i = 0; i < w; i++) {
128         int a, b, c, p, pa, pb, pc;
129 
130         a = src[i - bpp];
131         b = top[i];
132         c = top[i - bpp];
133 
134         p  = b - c;
135         pc = a - c;
136 
137         pa = abs(p);
138         pb = abs(pc);
139         pc = abs(p + pc);
140 
141         if (pa <= pb && pa <= pc)
142             p = a;
143         else if (pb <= pc)
144             p = b;
145         else
146             p = c;
147         dst[i] = src[i] - p;
148     }
149 }
150 
sub_left_prediction(PNGEncContext * c,uint8_t * dst,const uint8_t * src,int bpp,int size)151 static void sub_left_prediction(PNGEncContext *c, uint8_t *dst, const uint8_t *src, int bpp, int size)
152 {
153     const uint8_t *src1 = src + bpp;
154     const uint8_t *src2 = src;
155     int x, unaligned_w;
156 
157     memcpy(dst, src, bpp);
158     dst += bpp;
159     size -= bpp;
160     unaligned_w = FFMIN(32 - bpp, size);
161     for (x = 0; x < unaligned_w; x++)
162         *dst++ = *src1++ - *src2++;
163     size -= unaligned_w;
164     c->llvidencdsp.diff_bytes(dst, src1, src2, size);
165 }
166 
png_filter_row(PNGEncContext * c,uint8_t * dst,int filter_type,uint8_t * src,uint8_t * top,int size,int bpp)167 static void png_filter_row(PNGEncContext *c, uint8_t *dst, int filter_type,
168                            uint8_t *src, uint8_t *top, int size, int bpp)
169 {
170     int i;
171 
172     switch (filter_type) {
173     case PNG_FILTER_VALUE_NONE:
174         memcpy(dst, src, size);
175         break;
176     case PNG_FILTER_VALUE_SUB:
177         sub_left_prediction(c, dst, src, bpp, size);
178         break;
179     case PNG_FILTER_VALUE_UP:
180         c->llvidencdsp.diff_bytes(dst, src, top, size);
181         break;
182     case PNG_FILTER_VALUE_AVG:
183         for (i = 0; i < bpp; i++)
184             dst[i] = src[i] - (top[i] >> 1);
185         for (; i < size; i++)
186             dst[i] = src[i] - ((src[i - bpp] + top[i]) >> 1);
187         break;
188     case PNG_FILTER_VALUE_PAETH:
189         for (i = 0; i < bpp; i++)
190             dst[i] = src[i] - top[i];
191         sub_png_paeth_prediction(dst + i, src + i, top + i, size - i, bpp);
192         break;
193     }
194 }
195 
png_choose_filter(PNGEncContext * s,uint8_t * dst,uint8_t * src,uint8_t * top,int size,int bpp)196 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
197                                   uint8_t *src, uint8_t *top, int size, int bpp)
198 {
199     int pred = s->filter_type;
200     av_assert0(bpp || !pred);
201     if (!top && pred)
202         pred = PNG_FILTER_VALUE_SUB;
203     if (pred == PNG_FILTER_VALUE_MIXED) {
204         int i;
205         int cost, bcost = INT_MAX;
206         uint8_t *buf1 = dst, *buf2 = dst + size + 16;
207         for (pred = 0; pred < 5; pred++) {
208             png_filter_row(s, buf1 + 1, pred, src, top, size, bpp);
209             buf1[0] = pred;
210             cost = 0;
211             for (i = 0; i <= size; i++)
212                 cost += abs((int8_t) buf1[i]);
213             if (cost < bcost) {
214                 bcost = cost;
215                 FFSWAP(uint8_t *, buf1, buf2);
216             }
217         }
218         return buf2;
219     } else {
220         png_filter_row(s, dst + 1, pred, src, top, size, bpp);
221         dst[0] = pred;
222         return dst;
223     }
224 }
225 
png_write_chunk(uint8_t ** f,uint32_t tag,const uint8_t * buf,int length)226 static void png_write_chunk(uint8_t **f, uint32_t tag,
227                             const uint8_t *buf, int length)
228 {
229     const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
230     uint32_t crc = ~0U;
231     uint8_t tagbuf[4];
232 
233     bytestream_put_be32(f, length);
234     AV_WL32(tagbuf, tag);
235     crc = av_crc(crc_table, crc, tagbuf, 4);
236     bytestream_put_be32(f, av_bswap32(tag));
237     if (length > 0) {
238         crc = av_crc(crc_table, crc, buf, length);
239         if (*f != buf)
240             memcpy(*f, buf, length);
241         *f += length;
242     }
243     bytestream_put_be32(f, ~crc);
244 }
245 
png_write_image_data(AVCodecContext * avctx,const uint8_t * buf,int length)246 static void png_write_image_data(AVCodecContext *avctx,
247                                  const uint8_t *buf, int length)
248 {
249     PNGEncContext *s = avctx->priv_data;
250     const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
251     uint32_t crc = ~0U;
252 
253     if (avctx->codec_id == AV_CODEC_ID_PNG || avctx->frame_number == 0) {
254         png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), buf, length);
255         return;
256     }
257 
258     bytestream_put_be32(&s->bytestream, length + 4);
259 
260     bytestream_put_be32(&s->bytestream, MKBETAG('f', 'd', 'A', 'T'));
261     bytestream_put_be32(&s->bytestream, s->sequence_number);
262     crc = av_crc(crc_table, crc, s->bytestream - 8, 8);
263 
264     crc = av_crc(crc_table, crc, buf, length);
265     memcpy(s->bytestream, buf, length);
266     s->bytestream += length;
267 
268     bytestream_put_be32(&s->bytestream, ~crc);
269 
270     ++s->sequence_number;
271 }
272 
273 /* XXX: do filtering */
png_write_row(AVCodecContext * avctx,const uint8_t * data,int size)274 static int png_write_row(AVCodecContext *avctx, const uint8_t *data, int size)
275 {
276     PNGEncContext *s = avctx->priv_data;
277     z_stream *const zstream = &s->zstream.zstream;
278     int ret;
279 
280     zstream->avail_in = size;
281     zstream->next_in  = data;
282     while (zstream->avail_in > 0) {
283         ret = deflate(zstream, Z_NO_FLUSH);
284         if (ret != Z_OK)
285             return -1;
286         if (zstream->avail_out == 0) {
287             if (s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
288                 png_write_image_data(avctx, s->buf, IOBUF_SIZE);
289             zstream->avail_out = IOBUF_SIZE;
290             zstream->next_out  = s->buf;
291         }
292     }
293     return 0;
294 }
295 
296 #define AV_WB32_PNG(buf, n) AV_WB32(buf, lrint((n) * 100000))
png_get_chrm(enum AVColorPrimaries prim,uint8_t * buf)297 static int png_get_chrm(enum AVColorPrimaries prim,  uint8_t *buf)
298 {
299     double rx, ry, gx, gy, bx, by, wx = 0.3127, wy = 0.3290;
300     switch (prim) {
301         case AVCOL_PRI_BT709:
302             rx = 0.640; ry = 0.330;
303             gx = 0.300; gy = 0.600;
304             bx = 0.150; by = 0.060;
305             break;
306         case AVCOL_PRI_BT470M:
307             rx = 0.670; ry = 0.330;
308             gx = 0.210; gy = 0.710;
309             bx = 0.140; by = 0.080;
310             wx = 0.310; wy = 0.316;
311             break;
312         case AVCOL_PRI_BT470BG:
313             rx = 0.640; ry = 0.330;
314             gx = 0.290; gy = 0.600;
315             bx = 0.150; by = 0.060;
316             break;
317         case AVCOL_PRI_SMPTE170M:
318         case AVCOL_PRI_SMPTE240M:
319             rx = 0.630; ry = 0.340;
320             gx = 0.310; gy = 0.595;
321             bx = 0.155; by = 0.070;
322             break;
323         case AVCOL_PRI_BT2020:
324             rx = 0.708; ry = 0.292;
325             gx = 0.170; gy = 0.797;
326             bx = 0.131; by = 0.046;
327             break;
328         default:
329             return 0;
330     }
331 
332     AV_WB32_PNG(buf     , wx); AV_WB32_PNG(buf + 4 , wy);
333     AV_WB32_PNG(buf + 8 , rx); AV_WB32_PNG(buf + 12, ry);
334     AV_WB32_PNG(buf + 16, gx); AV_WB32_PNG(buf + 20, gy);
335     AV_WB32_PNG(buf + 24, bx); AV_WB32_PNG(buf + 28, by);
336     return 1;
337 }
338 
png_get_gama(enum AVColorTransferCharacteristic trc,uint8_t * buf)339 static int png_get_gama(enum AVColorTransferCharacteristic trc, uint8_t *buf)
340 {
341     double gamma = avpriv_get_gamma_from_trc(trc);
342     if (gamma <= 1e-6)
343         return 0;
344 
345     AV_WB32_PNG(buf, 1.0 / gamma);
346     return 1;
347 }
348 
png_write_iccp(PNGEncContext * s,const AVFrameSideData * sd)349 static int png_write_iccp(PNGEncContext *s, const AVFrameSideData *sd)
350 {
351     z_stream *const zstream = &s->zstream.zstream;
352     const AVDictionaryEntry *entry;
353     const char *name;
354     uint8_t *start, *buf;
355     int ret;
356 
357     if (!sd || !sd->size)
358         return 0;
359     zstream->next_in  = sd->data;
360     zstream->avail_in = sd->size;
361 
362     /* write the chunk contents first */
363     start = s->bytestream + 8; /* make room for iCCP tag + length */
364     buf = start;
365 
366     /* profile description */
367     entry = av_dict_get(sd->metadata, "name", NULL, 0);
368     name = (entry && entry->value[0]) ? entry->value : "icc";
369     for (int i = 0;; i++) {
370         char c = (i == 79) ? 0 : name[i];
371         bytestream_put_byte(&buf, c);
372         if (!c)
373             break;
374     }
375 
376     /* compression method and profile data */
377     bytestream_put_byte(&buf, 0);
378     zstream->next_out  = buf;
379     zstream->avail_out = s->bytestream_end - buf;
380     ret = deflate(zstream, Z_FINISH);
381     deflateReset(zstream);
382     if (ret != Z_STREAM_END)
383         return AVERROR_EXTERNAL;
384 
385     /* rewind to the start and write the chunk header/crc */
386     png_write_chunk(&s->bytestream, MKTAG('i', 'C', 'C', 'P'), start,
387                     zstream->next_out - start);
388     return 0;
389 }
390 
encode_headers(AVCodecContext * avctx,const AVFrame * pict)391 static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
392 {
393     AVFrameSideData *side_data;
394     PNGEncContext *s = avctx->priv_data;
395     int ret;
396 
397     /* write png header */
398     AV_WB32(s->buf, avctx->width);
399     AV_WB32(s->buf + 4, avctx->height);
400     s->buf[8]  = s->bit_depth;
401     s->buf[9]  = s->color_type;
402     s->buf[10] = 0; /* compression type */
403     s->buf[11] = 0; /* filter type */
404     s->buf[12] = s->is_progressive; /* interlace type */
405     png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
406 
407     /* write physical information */
408     if (s->dpm) {
409       AV_WB32(s->buf, s->dpm);
410       AV_WB32(s->buf + 4, s->dpm);
411       s->buf[8] = 1; /* unit specifier is meter */
412     } else {
413       AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
414       AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
415       s->buf[8] = 0; /* unit specifier is unknown */
416     }
417     png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
418 
419     /* write stereoscopic information */
420     side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_STEREO3D);
421     if (side_data) {
422         AVStereo3D *stereo3d = (AVStereo3D *)side_data->data;
423         switch (stereo3d->type) {
424             case AV_STEREO3D_SIDEBYSIDE:
425                 s->buf[0] = ((stereo3d->flags & AV_STEREO3D_FLAG_INVERT) == 0) ? 1 : 0;
426                 png_write_chunk(&s->bytestream, MKTAG('s', 'T', 'E', 'R'), s->buf, 1);
427                 break;
428             case AV_STEREO3D_2D:
429                 break;
430             default:
431                 av_log(avctx, AV_LOG_WARNING, "Only side-by-side stereo3d flag can be defined within sTER chunk\n");
432                 break;
433         }
434     }
435 
436     /* write colorspace information */
437     if (pict->color_primaries == AVCOL_PRI_BT709 &&
438         pict->color_trc == AVCOL_TRC_IEC61966_2_1) {
439         s->buf[0] = 1; /* rendering intent, relative colorimetric by default */
440         png_write_chunk(&s->bytestream, MKTAG('s', 'R', 'G', 'B'), s->buf, 1);
441     }
442 
443     if (png_get_chrm(pict->color_primaries, s->buf))
444         png_write_chunk(&s->bytestream, MKTAG('c', 'H', 'R', 'M'), s->buf, 32);
445     if (png_get_gama(pict->color_trc, s->buf))
446         png_write_chunk(&s->bytestream, MKTAG('g', 'A', 'M', 'A'), s->buf, 4);
447 
448     side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
449     if ((ret = png_write_iccp(s, side_data)))
450         return ret;
451 
452     /* put the palette if needed, must be after colorspace information */
453     if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
454         int has_alpha, alpha, i;
455         unsigned int v;
456         uint32_t *palette;
457         uint8_t *ptr, *alpha_ptr;
458 
459         palette   = (uint32_t *)pict->data[1];
460         ptr       = s->buf;
461         alpha_ptr = s->buf + 256 * 3;
462         has_alpha = 0;
463         for (i = 0; i < 256; i++) {
464             v     = palette[i];
465             alpha = v >> 24;
466             if (alpha != 0xff)
467                 has_alpha = 1;
468             *alpha_ptr++ = alpha;
469             bytestream_put_be24(&ptr, v);
470         }
471         png_write_chunk(&s->bytestream,
472                         MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
473         if (has_alpha) {
474             png_write_chunk(&s->bytestream,
475                             MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
476         }
477     }
478 
479     return 0;
480 }
481 
encode_frame(AVCodecContext * avctx,const AVFrame * pict)482 static int encode_frame(AVCodecContext *avctx, const AVFrame *pict)
483 {
484     PNGEncContext *s       = avctx->priv_data;
485     z_stream *const zstream = &s->zstream.zstream;
486     const AVFrame *const p = pict;
487     int y, len, ret;
488     int row_size, pass_row_size;
489     uint8_t *ptr, *top, *crow_buf, *crow;
490     uint8_t *crow_base       = NULL;
491     uint8_t *progressive_buf = NULL;
492     uint8_t *top_buf         = NULL;
493 
494     row_size = (pict->width * s->bits_per_pixel + 7) >> 3;
495 
496     crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
497     if (!crow_base) {
498         ret = AVERROR(ENOMEM);
499         goto the_end;
500     }
501     // pixel data should be aligned, but there's a control byte before it
502     crow_buf = crow_base + 15;
503     if (s->is_progressive) {
504         progressive_buf = av_malloc(row_size + 1);
505         top_buf = av_malloc(row_size + 1);
506         if (!progressive_buf || !top_buf) {
507             ret = AVERROR(ENOMEM);
508             goto the_end;
509         }
510     }
511 
512     /* put each row */
513     zstream->avail_out = IOBUF_SIZE;
514     zstream->next_out  = s->buf;
515     if (s->is_progressive) {
516         int pass;
517 
518         for (pass = 0; pass < NB_PASSES; pass++) {
519             /* NOTE: a pass is completely omitted if no pixels would be
520              * output */
521             pass_row_size = ff_png_pass_row_size(pass, s->bits_per_pixel, pict->width);
522             if (pass_row_size > 0) {
523                 top = NULL;
524                 for (y = 0; y < pict->height; y++)
525                     if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
526                         ptr = p->data[0] + y * p->linesize[0];
527                         FFSWAP(uint8_t *, progressive_buf, top_buf);
528                         png_get_interlaced_row(progressive_buf, pass_row_size,
529                                                s->bits_per_pixel, pass,
530                                                ptr, pict->width);
531                         crow = png_choose_filter(s, crow_buf, progressive_buf,
532                                                  top, pass_row_size, s->bits_per_pixel >> 3);
533                         png_write_row(avctx, crow, pass_row_size + 1);
534                         top = progressive_buf;
535                     }
536             }
537         }
538     } else {
539         top = NULL;
540         for (y = 0; y < pict->height; y++) {
541             ptr = p->data[0] + y * p->linesize[0];
542             crow = png_choose_filter(s, crow_buf, ptr, top,
543                                      row_size, s->bits_per_pixel >> 3);
544             png_write_row(avctx, crow, row_size + 1);
545             top = ptr;
546         }
547     }
548     /* compress last bytes */
549     for (;;) {
550         ret = deflate(zstream, Z_FINISH);
551         if (ret == Z_OK || ret == Z_STREAM_END) {
552             len = IOBUF_SIZE - zstream->avail_out;
553             if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
554                 png_write_image_data(avctx, s->buf, len);
555             }
556             zstream->avail_out = IOBUF_SIZE;
557             zstream->next_out  = s->buf;
558             if (ret == Z_STREAM_END)
559                 break;
560         } else {
561             ret = -1;
562             goto the_end;
563         }
564     }
565 
566     ret = 0;
567 
568 the_end:
569     av_freep(&crow_base);
570     av_freep(&progressive_buf);
571     av_freep(&top_buf);
572     deflateReset(zstream);
573     return ret;
574 }
575 
add_icc_profile_size(AVCodecContext * avctx,const AVFrame * pict,uint64_t * max_packet_size)576 static int add_icc_profile_size(AVCodecContext *avctx, const AVFrame *pict,
577                                 uint64_t *max_packet_size)
578 {
579     PNGEncContext *s = avctx->priv_data;
580     const AVFrameSideData *sd;
581     const int hdr_size = 128;
582     uint64_t new_pkt_size;
583     uLong bound;
584 
585     if (!pict)
586         return 0;
587     sd = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
588     if (!sd || !sd->size)
589         return 0;
590     if (sd->size != (uLong) sd->size)
591         return AVERROR_INVALIDDATA;
592 
593     bound = deflateBound(&s->zstream.zstream, sd->size);
594     if (bound > INT32_MAX - hdr_size)
595         return AVERROR_INVALIDDATA;
596 
597     new_pkt_size = *max_packet_size + bound + hdr_size;
598     if (new_pkt_size < *max_packet_size)
599         return AVERROR_INVALIDDATA;
600     *max_packet_size = new_pkt_size;
601     return 0;
602 }
603 
encode_png(AVCodecContext * avctx,AVPacket * pkt,const AVFrame * pict,int * got_packet)604 static int encode_png(AVCodecContext *avctx, AVPacket *pkt,
605                       const AVFrame *pict, int *got_packet)
606 {
607     PNGEncContext *s = avctx->priv_data;
608     int ret;
609     int enc_row_size;
610     uint64_t max_packet_size;
611 
612     enc_row_size    = deflateBound(&s->zstream.zstream,
613                                    (avctx->width * s->bits_per_pixel + 7) >> 3);
614     max_packet_size =
615         AV_INPUT_BUFFER_MIN_SIZE + // headers
616         avctx->height * (
617             enc_row_size +
618             12 * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // IDAT * ceil(enc_row_size / IOBUF_SIZE)
619         );
620     if ((ret = add_icc_profile_size(avctx, pict, &max_packet_size)))
621         return ret;
622     ret = ff_alloc_packet(avctx, pkt, max_packet_size);
623     if (ret < 0)
624         return ret;
625 
626     s->bytestream_start =
627     s->bytestream       = pkt->data;
628     s->bytestream_end   = pkt->data + pkt->size;
629 
630     AV_WB64(s->bytestream, PNGSIG);
631     s->bytestream += 8;
632 
633     ret = encode_headers(avctx, pict);
634     if (ret < 0)
635         return ret;
636 
637     ret = encode_frame(avctx, pict);
638     if (ret < 0)
639         return ret;
640 
641     png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
642 
643     pkt->size = s->bytestream - s->bytestream_start;
644     pkt->flags |= AV_PKT_FLAG_KEY;
645     *got_packet = 1;
646 
647     return 0;
648 }
649 
apng_do_inverse_blend(AVFrame * output,const AVFrame * input,APNGFctlChunk * fctl_chunk,uint8_t bpp)650 static int apng_do_inverse_blend(AVFrame *output, const AVFrame *input,
651                                   APNGFctlChunk *fctl_chunk, uint8_t bpp)
652 {
653     // output: background, input: foreground
654     // output the image such that when blended with the background, will produce the foreground
655 
656     unsigned int x, y;
657     unsigned int leftmost_x = input->width;
658     unsigned int rightmost_x = 0;
659     unsigned int topmost_y = input->height;
660     unsigned int bottommost_y = 0;
661     const uint8_t *input_data = input->data[0];
662     uint8_t *output_data = output->data[0];
663     ptrdiff_t input_linesize = input->linesize[0];
664     ptrdiff_t output_linesize = output->linesize[0];
665 
666     // Find bounding box of changes
667     for (y = 0; y < input->height; ++y) {
668         for (x = 0; x < input->width; ++x) {
669             if (!memcmp(input_data + bpp * x, output_data + bpp * x, bpp))
670                 continue;
671 
672             if (x < leftmost_x)
673                 leftmost_x = x;
674             if (x >= rightmost_x)
675                 rightmost_x = x + 1;
676             if (y < topmost_y)
677                 topmost_y = y;
678             if (y >= bottommost_y)
679                 bottommost_y = y + 1;
680         }
681 
682         input_data += input_linesize;
683         output_data += output_linesize;
684     }
685 
686     if (leftmost_x == input->width && rightmost_x == 0) {
687         // Empty frame
688         // APNG does not support empty frames, so we make it a 1x1 frame
689         leftmost_x = topmost_y = 0;
690         rightmost_x = bottommost_y = 1;
691     }
692 
693     // Do actual inverse blending
694     if (fctl_chunk->blend_op == APNG_BLEND_OP_SOURCE) {
695         output_data = output->data[0];
696         for (y = topmost_y; y < bottommost_y; ++y) {
697             memcpy(output_data,
698                    input->data[0] + input_linesize * y + bpp * leftmost_x,
699                    bpp * (rightmost_x - leftmost_x));
700             output_data += output_linesize;
701         }
702     } else { // APNG_BLEND_OP_OVER
703         size_t transparent_palette_index;
704         uint32_t *palette;
705 
706         switch (input->format) {
707         case AV_PIX_FMT_RGBA64BE:
708         case AV_PIX_FMT_YA16BE:
709         case AV_PIX_FMT_RGBA:
710         case AV_PIX_FMT_GRAY8A:
711             break;
712 
713         case AV_PIX_FMT_PAL8:
714             palette = (uint32_t*)input->data[1];
715             for (transparent_palette_index = 0; transparent_palette_index < 256; ++transparent_palette_index)
716                 if (palette[transparent_palette_index] >> 24 == 0)
717                     break;
718             break;
719 
720         default:
721             // No alpha, so blending not possible
722             return -1;
723         }
724 
725         for (y = topmost_y; y < bottommost_y; ++y) {
726             uint8_t *foreground = input->data[0] + input_linesize * y + bpp * leftmost_x;
727             uint8_t *background = output->data[0] + output_linesize * y + bpp * leftmost_x;
728             output_data = output->data[0] + output_linesize * (y - topmost_y);
729             for (x = leftmost_x; x < rightmost_x; ++x, foreground += bpp, background += bpp, output_data += bpp) {
730                 if (!memcmp(foreground, background, bpp)) {
731                     if (input->format == AV_PIX_FMT_PAL8) {
732                         if (transparent_palette_index == 256) {
733                             // Need fully transparent colour, but none exists
734                             return -1;
735                         }
736 
737                         *output_data = transparent_palette_index;
738                     } else {
739                         memset(output_data, 0, bpp);
740                     }
741                     continue;
742                 }
743 
744                 // Check for special alpha values, since full inverse
745                 // alpha-on-alpha blending is rarely possible, and when
746                 // possible, doesn't compress much better than
747                 // APNG_BLEND_OP_SOURCE blending
748                 switch (input->format) {
749                 case AV_PIX_FMT_RGBA64BE:
750                     if (((uint16_t*)foreground)[3] == 0xffff ||
751                         ((uint16_t*)background)[3] == 0)
752                         break;
753                     return -1;
754 
755                 case AV_PIX_FMT_YA16BE:
756                     if (((uint16_t*)foreground)[1] == 0xffff ||
757                         ((uint16_t*)background)[1] == 0)
758                         break;
759                     return -1;
760 
761                 case AV_PIX_FMT_RGBA:
762                     if (foreground[3] == 0xff || background[3] == 0)
763                         break;
764                     return -1;
765 
766                 case AV_PIX_FMT_GRAY8A:
767                     if (foreground[1] == 0xff || background[1] == 0)
768                         break;
769                     return -1;
770 
771                 case AV_PIX_FMT_PAL8:
772                     if (palette[*foreground] >> 24 == 0xff ||
773                         palette[*background] >> 24 == 0)
774                         break;
775                     return -1;
776                 }
777 
778                 memmove(output_data, foreground, bpp);
779             }
780         }
781     }
782 
783     output->width = rightmost_x - leftmost_x;
784     output->height = bottommost_y - topmost_y;
785     fctl_chunk->width = output->width;
786     fctl_chunk->height = output->height;
787     fctl_chunk->x_offset = leftmost_x;
788     fctl_chunk->y_offset = topmost_y;
789 
790     return 0;
791 }
792 
apng_encode_frame(AVCodecContext * avctx,const AVFrame * pict,APNGFctlChunk * best_fctl_chunk,APNGFctlChunk * best_last_fctl_chunk)793 static int apng_encode_frame(AVCodecContext *avctx, const AVFrame *pict,
794                              APNGFctlChunk *best_fctl_chunk, APNGFctlChunk *best_last_fctl_chunk)
795 {
796     PNGEncContext *s = avctx->priv_data;
797     int ret;
798     unsigned int y;
799     AVFrame* diffFrame;
800     uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
801     uint8_t *original_bytestream, *original_bytestream_end;
802     uint8_t *temp_bytestream = 0, *temp_bytestream_end;
803     uint32_t best_sequence_number;
804     uint8_t *best_bytestream;
805     size_t best_bytestream_size = SIZE_MAX;
806     APNGFctlChunk last_fctl_chunk = *best_last_fctl_chunk;
807     APNGFctlChunk fctl_chunk = *best_fctl_chunk;
808 
809     if (avctx->frame_number == 0) {
810         best_fctl_chunk->width = pict->width;
811         best_fctl_chunk->height = pict->height;
812         best_fctl_chunk->x_offset = 0;
813         best_fctl_chunk->y_offset = 0;
814         best_fctl_chunk->blend_op = APNG_BLEND_OP_SOURCE;
815         return encode_frame(avctx, pict);
816     }
817 
818     diffFrame = av_frame_alloc();
819     if (!diffFrame)
820         return AVERROR(ENOMEM);
821 
822     diffFrame->format = pict->format;
823     diffFrame->width = pict->width;
824     diffFrame->height = pict->height;
825     if ((ret = av_frame_get_buffer(diffFrame, 0)) < 0)
826         goto fail;
827 
828     original_bytestream = s->bytestream;
829     original_bytestream_end = s->bytestream_end;
830 
831     temp_bytestream = av_malloc(original_bytestream_end - original_bytestream);
832     if (!temp_bytestream) {
833         ret = AVERROR(ENOMEM);
834         goto fail;
835     }
836     temp_bytestream_end = temp_bytestream + (original_bytestream_end - original_bytestream);
837 
838     for (last_fctl_chunk.dispose_op = 0; last_fctl_chunk.dispose_op < 3; ++last_fctl_chunk.dispose_op) {
839         // 0: APNG_DISPOSE_OP_NONE
840         // 1: APNG_DISPOSE_OP_BACKGROUND
841         // 2: APNG_DISPOSE_OP_PREVIOUS
842 
843         for (fctl_chunk.blend_op = 0; fctl_chunk.blend_op < 2; ++fctl_chunk.blend_op) {
844             // 0: APNG_BLEND_OP_SOURCE
845             // 1: APNG_BLEND_OP_OVER
846 
847             uint32_t original_sequence_number = s->sequence_number, sequence_number;
848             uint8_t *bytestream_start = s->bytestream;
849             size_t bytestream_size;
850 
851             // Do disposal
852             if (last_fctl_chunk.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
853                 diffFrame->width = pict->width;
854                 diffFrame->height = pict->height;
855                 ret = av_frame_copy(diffFrame, s->last_frame);
856                 if (ret < 0)
857                     goto fail;
858 
859                 if (last_fctl_chunk.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
860                     for (y = last_fctl_chunk.y_offset; y < last_fctl_chunk.y_offset + last_fctl_chunk.height; ++y) {
861                         size_t row_start = diffFrame->linesize[0] * y + bpp * last_fctl_chunk.x_offset;
862                         memset(diffFrame->data[0] + row_start, 0, bpp * last_fctl_chunk.width);
863                     }
864                 }
865             } else {
866                 if (!s->prev_frame)
867                     continue;
868 
869                 diffFrame->width = pict->width;
870                 diffFrame->height = pict->height;
871                 ret = av_frame_copy(diffFrame, s->prev_frame);
872                 if (ret < 0)
873                     goto fail;
874             }
875 
876             // Do inverse blending
877             if (apng_do_inverse_blend(diffFrame, pict, &fctl_chunk, bpp) < 0)
878                 continue;
879 
880             // Do encoding
881             ret = encode_frame(avctx, diffFrame);
882             sequence_number = s->sequence_number;
883             s->sequence_number = original_sequence_number;
884             bytestream_size = s->bytestream - bytestream_start;
885             s->bytestream = bytestream_start;
886             if (ret < 0)
887                 goto fail;
888 
889             if (bytestream_size < best_bytestream_size) {
890                 *best_fctl_chunk = fctl_chunk;
891                 *best_last_fctl_chunk = last_fctl_chunk;
892 
893                 best_sequence_number = sequence_number;
894                 best_bytestream = s->bytestream;
895                 best_bytestream_size = bytestream_size;
896 
897                 if (best_bytestream == original_bytestream) {
898                     s->bytestream = temp_bytestream;
899                     s->bytestream_end = temp_bytestream_end;
900                 } else {
901                     s->bytestream = original_bytestream;
902                     s->bytestream_end = original_bytestream_end;
903                 }
904             }
905         }
906     }
907 
908     s->sequence_number = best_sequence_number;
909     s->bytestream = original_bytestream + best_bytestream_size;
910     s->bytestream_end = original_bytestream_end;
911     if (best_bytestream != original_bytestream)
912         memcpy(original_bytestream, best_bytestream, best_bytestream_size);
913 
914     ret = 0;
915 
916 fail:
917     av_freep(&temp_bytestream);
918     av_frame_free(&diffFrame);
919     return ret;
920 }
921 
encode_apng(AVCodecContext * avctx,AVPacket * pkt,const AVFrame * pict,int * got_packet)922 static int encode_apng(AVCodecContext *avctx, AVPacket *pkt,
923                        const AVFrame *pict, int *got_packet)
924 {
925     PNGEncContext *s = avctx->priv_data;
926     int ret;
927     int enc_row_size;
928     uint64_t max_packet_size;
929     APNGFctlChunk fctl_chunk = {0};
930 
931     if (pict && s->color_type == PNG_COLOR_TYPE_PALETTE) {
932         uint32_t checksum = ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, pict->data[1], 256 * sizeof(uint32_t));
933 
934         if (avctx->frame_number == 0) {
935             s->palette_checksum = checksum;
936         } else if (checksum != s->palette_checksum) {
937             av_log(avctx, AV_LOG_ERROR,
938                    "Input contains more than one unique palette. APNG does not support multiple palettes.\n");
939             return -1;
940         }
941     }
942 
943     enc_row_size    = deflateBound(&s->zstream.zstream,
944                                    (avctx->width * s->bits_per_pixel + 7) >> 3);
945     max_packet_size =
946         AV_INPUT_BUFFER_MIN_SIZE + // headers
947         avctx->height * (
948             enc_row_size +
949             (4 + 12) * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // fdAT * ceil(enc_row_size / IOBUF_SIZE)
950         );
951     if ((ret = add_icc_profile_size(avctx, pict, &max_packet_size)))
952         return ret;
953     if (max_packet_size > INT_MAX)
954         return AVERROR(ENOMEM);
955 
956     if (avctx->frame_number == 0) {
957         if (!pict)
958             return AVERROR(EINVAL);
959 
960         s->bytestream = s->extra_data = av_malloc(AV_INPUT_BUFFER_MIN_SIZE);
961         if (!s->extra_data)
962             return AVERROR(ENOMEM);
963 
964         ret = encode_headers(avctx, pict);
965         if (ret < 0)
966             return ret;
967 
968         s->extra_data_size = s->bytestream - s->extra_data;
969 
970         s->last_frame_packet = av_malloc(max_packet_size);
971         if (!s->last_frame_packet)
972             return AVERROR(ENOMEM);
973     } else if (s->last_frame) {
974         ret = ff_get_encode_buffer(avctx, pkt, s->last_frame_packet_size, 0);
975         if (ret < 0)
976             return ret;
977 
978         memcpy(pkt->data, s->last_frame_packet, s->last_frame_packet_size);
979         pkt->pts = pkt->dts = s->last_frame->pts;
980     }
981 
982     if (pict) {
983         s->bytestream_start =
984         s->bytestream       = s->last_frame_packet;
985         s->bytestream_end   = s->bytestream + max_packet_size;
986 
987         // We're encoding the frame first, so we have to do a bit of shuffling around
988         // to have the image data write to the correct place in the buffer
989         fctl_chunk.sequence_number = s->sequence_number;
990         ++s->sequence_number;
991         s->bytestream += APNG_FCTL_CHUNK_SIZE + 12;
992 
993         ret = apng_encode_frame(avctx, pict, &fctl_chunk, &s->last_frame_fctl);
994         if (ret < 0)
995             return ret;
996 
997         fctl_chunk.delay_num = 0; // delay filled in during muxing
998         fctl_chunk.delay_den = 0;
999     } else {
1000         s->last_frame_fctl.dispose_op = APNG_DISPOSE_OP_NONE;
1001     }
1002 
1003     if (s->last_frame) {
1004         uint8_t* last_fctl_chunk_start = pkt->data;
1005         uint8_t buf[APNG_FCTL_CHUNK_SIZE];
1006         if (!s->extra_data_updated) {
1007             uint8_t *side_data = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, s->extra_data_size);
1008             if (!side_data)
1009                 return AVERROR(ENOMEM);
1010             memcpy(side_data, s->extra_data, s->extra_data_size);
1011             s->extra_data_updated = 1;
1012         }
1013 
1014         AV_WB32(buf + 0, s->last_frame_fctl.sequence_number);
1015         AV_WB32(buf + 4, s->last_frame_fctl.width);
1016         AV_WB32(buf + 8, s->last_frame_fctl.height);
1017         AV_WB32(buf + 12, s->last_frame_fctl.x_offset);
1018         AV_WB32(buf + 16, s->last_frame_fctl.y_offset);
1019         AV_WB16(buf + 20, s->last_frame_fctl.delay_num);
1020         AV_WB16(buf + 22, s->last_frame_fctl.delay_den);
1021         buf[24] = s->last_frame_fctl.dispose_op;
1022         buf[25] = s->last_frame_fctl.blend_op;
1023         png_write_chunk(&last_fctl_chunk_start, MKTAG('f', 'c', 'T', 'L'), buf, sizeof(buf));
1024 
1025         *got_packet = 1;
1026     }
1027 
1028     if (pict) {
1029         if (!s->last_frame) {
1030             s->last_frame = av_frame_alloc();
1031             if (!s->last_frame)
1032                 return AVERROR(ENOMEM);
1033         } else if (s->last_frame_fctl.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
1034             if (!s->prev_frame) {
1035                 s->prev_frame = av_frame_alloc();
1036                 if (!s->prev_frame)
1037                     return AVERROR(ENOMEM);
1038 
1039                 s->prev_frame->format = pict->format;
1040                 s->prev_frame->width = pict->width;
1041                 s->prev_frame->height = pict->height;
1042                 if ((ret = av_frame_get_buffer(s->prev_frame, 0)) < 0)
1043                     return ret;
1044             }
1045 
1046             // Do disposal, but not blending
1047             av_frame_copy(s->prev_frame, s->last_frame);
1048             if (s->last_frame_fctl.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
1049                 uint32_t y;
1050                 uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
1051                 for (y = s->last_frame_fctl.y_offset; y < s->last_frame_fctl.y_offset + s->last_frame_fctl.height; ++y) {
1052                     size_t row_start = s->prev_frame->linesize[0] * y + bpp * s->last_frame_fctl.x_offset;
1053                     memset(s->prev_frame->data[0] + row_start, 0, bpp * s->last_frame_fctl.width);
1054                 }
1055             }
1056         }
1057 
1058         av_frame_unref(s->last_frame);
1059         ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
1060         if (ret < 0)
1061             return ret;
1062 
1063         s->last_frame_fctl = fctl_chunk;
1064         s->last_frame_packet_size = s->bytestream - s->bytestream_start;
1065     } else {
1066         av_frame_free(&s->last_frame);
1067     }
1068 
1069     return 0;
1070 }
1071 
png_enc_init(AVCodecContext * avctx)1072 static av_cold int png_enc_init(AVCodecContext *avctx)
1073 {
1074     PNGEncContext *s = avctx->priv_data;
1075     int compression_level;
1076 
1077     switch (avctx->pix_fmt) {
1078     case AV_PIX_FMT_RGBA:
1079         avctx->bits_per_coded_sample = 32;
1080         break;
1081     case AV_PIX_FMT_RGB24:
1082         avctx->bits_per_coded_sample = 24;
1083         break;
1084     case AV_PIX_FMT_GRAY8:
1085         avctx->bits_per_coded_sample = 0x28;
1086         break;
1087     case AV_PIX_FMT_MONOBLACK:
1088         avctx->bits_per_coded_sample = 1;
1089         break;
1090     case AV_PIX_FMT_PAL8:
1091         avctx->bits_per_coded_sample = 8;
1092     }
1093 
1094     ff_llvidencdsp_init(&s->llvidencdsp);
1095 
1096     if (avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
1097         s->filter_type = PNG_FILTER_VALUE_NONE;
1098 
1099     if (s->dpi && s->dpm) {
1100       av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");
1101       return AVERROR(EINVAL);
1102     } else if (s->dpi) {
1103       s->dpm = s->dpi * 10000 / 254;
1104     }
1105 
1106     s->is_progressive = !!(avctx->flags & AV_CODEC_FLAG_INTERLACED_DCT);
1107     switch (avctx->pix_fmt) {
1108     case AV_PIX_FMT_RGBA64BE:
1109         s->bit_depth = 16;
1110         s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
1111         break;
1112     case AV_PIX_FMT_RGB48BE:
1113         s->bit_depth = 16;
1114         s->color_type = PNG_COLOR_TYPE_RGB;
1115         break;
1116     case AV_PIX_FMT_RGBA:
1117         s->bit_depth  = 8;
1118         s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
1119         break;
1120     case AV_PIX_FMT_RGB24:
1121         s->bit_depth  = 8;
1122         s->color_type = PNG_COLOR_TYPE_RGB;
1123         break;
1124     case AV_PIX_FMT_GRAY16BE:
1125         s->bit_depth  = 16;
1126         s->color_type = PNG_COLOR_TYPE_GRAY;
1127         break;
1128     case AV_PIX_FMT_GRAY8:
1129         s->bit_depth  = 8;
1130         s->color_type = PNG_COLOR_TYPE_GRAY;
1131         break;
1132     case AV_PIX_FMT_GRAY8A:
1133         s->bit_depth = 8;
1134         s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
1135         break;
1136     case AV_PIX_FMT_YA16BE:
1137         s->bit_depth = 16;
1138         s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
1139         break;
1140     case AV_PIX_FMT_MONOBLACK:
1141         s->bit_depth  = 1;
1142         s->color_type = PNG_COLOR_TYPE_GRAY;
1143         break;
1144     case AV_PIX_FMT_PAL8:
1145         s->bit_depth  = 8;
1146         s->color_type = PNG_COLOR_TYPE_PALETTE;
1147         break;
1148     default:
1149         return -1;
1150     }
1151     s->bits_per_pixel = ff_png_get_nb_channels(s->color_type) * s->bit_depth;
1152 
1153     compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT
1154                       ? Z_DEFAULT_COMPRESSION
1155                       : av_clip(avctx->compression_level, 0, 9);
1156     return ff_deflate_init(&s->zstream, compression_level, avctx);
1157 }
1158 
png_enc_close(AVCodecContext * avctx)1159 static av_cold int png_enc_close(AVCodecContext *avctx)
1160 {
1161     PNGEncContext *s = avctx->priv_data;
1162 
1163     ff_deflate_end(&s->zstream);
1164     av_frame_free(&s->last_frame);
1165     av_frame_free(&s->prev_frame);
1166     av_freep(&s->last_frame_packet);
1167     av_freep(&s->extra_data);
1168     s->extra_data_size = 0;
1169     return 0;
1170 }
1171 
1172 #define OFFSET(x) offsetof(PNGEncContext, x)
1173 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
1174 static const AVOption options[] = {
1175     {"dpi", "Set image resolution (in dots per inch)",  OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
1176     {"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
1177     { "pred", "Prediction method", OFFSET(filter_type), AV_OPT_TYPE_INT, { .i64 = PNG_FILTER_VALUE_NONE }, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED, VE, "pred" },
1178         { "none",  NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_NONE },  INT_MIN, INT_MAX, VE, "pred" },
1179         { "sub",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_SUB },   INT_MIN, INT_MAX, VE, "pred" },
1180         { "up",    NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_UP },    INT_MIN, INT_MAX, VE, "pred" },
1181         { "avg",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_AVG },   INT_MIN, INT_MAX, VE, "pred" },
1182         { "paeth", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_PAETH }, INT_MIN, INT_MAX, VE, "pred" },
1183         { "mixed", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_MIXED }, INT_MIN, INT_MAX, VE, "pred" },
1184     { NULL},
1185 };
1186 
1187 static const AVClass pngenc_class = {
1188     .class_name = "(A)PNG encoder",
1189     .item_name  = av_default_item_name,
1190     .option     = options,
1191     .version    = LIBAVUTIL_VERSION_INT,
1192 };
1193 
1194 const FFCodec ff_png_encoder = {
1195     .p.name         = "png",
1196     .p.long_name    = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
1197     .p.type         = AVMEDIA_TYPE_VIDEO,
1198     .p.id           = AV_CODEC_ID_PNG,
1199     .priv_data_size = sizeof(PNGEncContext),
1200     .init           = png_enc_init,
1201     .close          = png_enc_close,
1202     FF_CODEC_ENCODE_CB(encode_png),
1203     .p.capabilities = AV_CODEC_CAP_FRAME_THREADS,
1204     .p.pix_fmts     = (const enum AVPixelFormat[]) {
1205         AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
1206         AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
1207         AV_PIX_FMT_PAL8,
1208         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
1209         AV_PIX_FMT_GRAY16BE, AV_PIX_FMT_YA16BE,
1210         AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
1211     },
1212     .p.priv_class   = &pngenc_class,
1213     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
1214 };
1215 
1216 const FFCodec ff_apng_encoder = {
1217     .p.name         = "apng",
1218     .p.long_name    = NULL_IF_CONFIG_SMALL("APNG (Animated Portable Network Graphics) image"),
1219     .p.type         = AVMEDIA_TYPE_VIDEO,
1220     .p.id           = AV_CODEC_ID_APNG,
1221     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
1222     .priv_data_size = sizeof(PNGEncContext),
1223     .init           = png_enc_init,
1224     .close          = png_enc_close,
1225     FF_CODEC_ENCODE_CB(encode_apng),
1226     .p.pix_fmts     = (const enum AVPixelFormat[]) {
1227         AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
1228         AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
1229         AV_PIX_FMT_PAL8,
1230         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
1231         AV_PIX_FMT_GRAY16BE, AV_PIX_FMT_YA16BE,
1232         AV_PIX_FMT_NONE
1233     },
1234     .p.priv_class   = &pngenc_class,
1235     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
1236 };
1237