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pngdec.c
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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 //#define DEBUG
23 
24 #include "libavutil/bprint.h"
25 #include "libavutil/imgutils.h"
26 #include "avcodec.h"
27 #include "bytestream.h"
28 #include "internal.h"
29 #include "png.h"
30 #include "pngdsp.h"
31 #include "thread.h"
32 
33 #include <zlib.h>
34 
35 typedef struct PNGDecContext {
38 
42 
43  int state;
44  int width, height;
45  int bit_depth;
50  int channels;
52  int bpp;
53 
56  uint32_t palette[256];
59  unsigned int last_row_size;
61  unsigned int tmp_row_size;
64  int pass;
65  int crow_size; /* compressed row size (include filter type) */
66  int row_size; /* decompressed row size */
67  int pass_row_size; /* decompress row size of the current pass */
68  int y;
69  z_stream zstream;
71 
72 /* Mask to determine which pixels are valid in a pass */
73 static const uint8_t png_pass_mask[NB_PASSES] = {
74  0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
75 };
76 
77 /* Mask to determine which y pixels can be written in a pass */
79  0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
80 };
81 
82 /* Mask to determine which pixels to overwrite while displaying */
84  0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
85 };
86 
87 /* NOTE: we try to construct a good looking image at each pass. width
88  * is the original image width. We also do pixel format conversion at
89  * this stage */
90 static void png_put_interlaced_row(uint8_t *dst, int width,
91  int bits_per_pixel, int pass,
92  int color_type, const uint8_t *src)
93 {
94  int x, mask, dsp_mask, j, src_x, b, bpp;
95  uint8_t *d;
96  const uint8_t *s;
97 
98  mask = png_pass_mask[pass];
99  dsp_mask = png_pass_dsp_mask[pass];
100 
101  switch (bits_per_pixel) {
102  case 1:
103  src_x = 0;
104  for (x = 0; x < width; x++) {
105  j = (x & 7);
106  if ((dsp_mask << j) & 0x80) {
107  b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
108  dst[x >> 3] &= 0xFF7F>>j;
109  dst[x >> 3] |= b << (7 - j);
110  }
111  if ((mask << j) & 0x80)
112  src_x++;
113  }
114  break;
115  case 2:
116  src_x = 0;
117  for (x = 0; x < width; x++) {
118  int j2 = 2 * (x & 3);
119  j = (x & 7);
120  if ((dsp_mask << j) & 0x80) {
121  b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
122  dst[x >> 2] &= 0xFF3F>>j2;
123  dst[x >> 2] |= b << (6 - j2);
124  }
125  if ((mask << j) & 0x80)
126  src_x++;
127  }
128  break;
129  case 4:
130  src_x = 0;
131  for (x = 0; x < width; x++) {
132  int j2 = 4*(x&1);
133  j = (x & 7);
134  if ((dsp_mask << j) & 0x80) {
135  b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
136  dst[x >> 1] &= 0xFF0F>>j2;
137  dst[x >> 1] |= b << (4 - j2);
138  }
139  if ((mask << j) & 0x80)
140  src_x++;
141  }
142  break;
143  default:
144  bpp = bits_per_pixel >> 3;
145  d = dst;
146  s = src;
147  for (x = 0; x < width; x++) {
148  j = x & 7;
149  if ((dsp_mask << j) & 0x80) {
150  memcpy(d, s, bpp);
151  }
152  d += bpp;
153  if ((mask << j) & 0x80)
154  s += bpp;
155  }
156  break;
157  }
158 }
159 
161  int w, int bpp)
162 {
163  int i;
164  for (i = 0; i < w; i++) {
165  int a, b, c, p, pa, pb, pc;
166 
167  a = dst[i - bpp];
168  b = top[i];
169  c = top[i - bpp];
170 
171  p = b - c;
172  pc = a - c;
173 
174  pa = abs(p);
175  pb = abs(pc);
176  pc = abs(p + pc);
177 
178  if (pa <= pb && pa <= pc)
179  p = a;
180  else if (pb <= pc)
181  p = b;
182  else
183  p = c;
184  dst[i] = p + src[i];
185  }
186 }
187 
188 #define UNROLL1(bpp, op) { \
189  r = dst[0]; \
190  if (bpp >= 2) \
191  g = dst[1]; \
192  if (bpp >= 3) \
193  b = dst[2]; \
194  if (bpp >= 4) \
195  a = dst[3]; \
196  for (; i <= size - bpp; i += bpp) { \
197  dst[i + 0] = r = op(r, src[i + 0], last[i + 0]); \
198  if (bpp == 1) \
199  continue; \
200  dst[i + 1] = g = op(g, src[i + 1], last[i + 1]); \
201  if (bpp == 2) \
202  continue; \
203  dst[i + 2] = b = op(b, src[i + 2], last[i + 2]); \
204  if (bpp == 3) \
205  continue; \
206  dst[i + 3] = a = op(a, src[i + 3], last[i + 3]); \
207  } \
208 }
209 
210 #define UNROLL_FILTER(op)\
211  if (bpp == 1) UNROLL1(1, op)\
212  else if (bpp == 2) UNROLL1(2, op)\
213  else if (bpp == 3) UNROLL1(3, op)\
214  else if (bpp == 4) UNROLL1(4, op)\
215  for (; i < size; i++) {\
216  dst[i] = op(dst[i - bpp], src[i], last[i]);\
217  }\
218 
219 /* NOTE: 'dst' can be equal to 'last' */
220 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
221  uint8_t *src, uint8_t *last, int size, int bpp)
222 {
223  int i, p, r, g, b, a;
224 
225  switch (filter_type) {
227  memcpy(dst, src, size);
228  break;
230  for (i = 0; i < bpp; i++)
231  dst[i] = src[i];
232  if (bpp == 4) {
233  p = *(int *)dst;
234  for (; i < size; i += bpp) {
235  unsigned s = *(int *)(src + i);
236  p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
237  *(int *)(dst + i) = p;
238  }
239  } else {
240 #define OP_SUB(x, s, l) ((x) + (s))
242  }
243  break;
244  case PNG_FILTER_VALUE_UP:
245  dsp->add_bytes_l2(dst, src, last, size);
246  break;
248  for (i = 0; i < bpp; i++) {
249  p = (last[i] >> 1);
250  dst[i] = p + src[i];
251  }
252 #define OP_AVG(x, s, l) (((((x) + (l)) >> 1) + (s)) & 0xff)
254  break;
256  for (i = 0; i < bpp; i++) {
257  p = last[i];
258  dst[i] = p + src[i];
259  }
260  if (bpp > 2 && size > 4) {
261  /* would write off the end of the array if we let it process
262  * the last pixel with bpp=3 */
263  int w = bpp == 4 ? size : size - 3;
264  dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
265  i = w;
266  }
267  ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
268  break;
269  }
270 }
271 
272 /* This used to be called "deloco" in FFmpeg
273  * and is actually an inverse reversible colorspace transformation */
274 #define YUV2RGB(NAME, TYPE) \
275 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
276 { \
277  int i; \
278  for (i = 0; i < size; i += 3 + alpha) { \
279  int g = dst [i + 1]; \
280  dst[i + 0] += g; \
281  dst[i + 2] += g; \
282  } \
283 }
284 
285 YUV2RGB(rgb8, uint8_t)
286 YUV2RGB(rgb16, uint16_t)
287 
288 /* process exactly one decompressed row */
290 {
291  uint8_t *ptr, *last_row;
292  int got_line;
293 
294  if (!s->interlace_type) {
295  ptr = s->image_buf + s->image_linesize * s->y;
296  if (s->y == 0)
297  last_row = s->last_row;
298  else
299  last_row = ptr - s->image_linesize;
300 
301  png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
302  last_row, s->row_size, s->bpp);
303  /* loco lags by 1 row so that it doesn't interfere with top prediction */
304  if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
305  if (s->bit_depth == 16) {
306  deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
307  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
308  } else {
309  deloco_rgb8(ptr - s->image_linesize, s->row_size,
310  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
311  }
312  }
313  s->y++;
314  if (s->y == s->height) {
315  s->state |= PNG_ALLIMAGE;
316  if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
317  if (s->bit_depth == 16) {
318  deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
319  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
320  } else {
321  deloco_rgb8(ptr, s->row_size,
322  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
323  }
324  }
325  }
326  } else {
327  got_line = 0;
328  for (;;) {
329  ptr = s->image_buf + s->image_linesize * s->y;
330  if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
331  /* if we already read one row, it is time to stop to
332  * wait for the next one */
333  if (got_line)
334  break;
335  png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
336  s->last_row, s->pass_row_size, s->bpp);
337  FFSWAP(uint8_t *, s->last_row, s->tmp_row);
338  FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
339  got_line = 1;
340  }
341  if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
342  png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
343  s->color_type, s->last_row);
344  }
345  s->y++;
346  if (s->y == s->height) {
347  memset(s->last_row, 0, s->row_size);
348  for (;;) {
349  if (s->pass == NB_PASSES - 1) {
350  s->state |= PNG_ALLIMAGE;
351  goto the_end;
352  } else {
353  s->pass++;
354  s->y = 0;
355  s->pass_row_size = ff_png_pass_row_size(s->pass,
356  s->bits_per_pixel,
357  s->width);
358  s->crow_size = s->pass_row_size + 1;
359  if (s->pass_row_size != 0)
360  break;
361  /* skip pass if empty row */
362  }
363  }
364  }
365  }
366 the_end:;
367  }
368 }
369 
371 {
372  int ret;
373  s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
374  s->zstream.next_in = (unsigned char *)s->gb.buffer;
375  bytestream2_skip(&s->gb, length);
376 
377  /* decode one line if possible */
378  while (s->zstream.avail_in > 0) {
379  ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
380  if (ret != Z_OK && ret != Z_STREAM_END) {
381  av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
382  return AVERROR_EXTERNAL;
383  }
384  if (s->zstream.avail_out == 0) {
385  if (!(s->state & PNG_ALLIMAGE)) {
386  png_handle_row(s);
387  }
388  s->zstream.avail_out = s->crow_size;
389  s->zstream.next_out = s->crow_buf;
390  }
391  if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
392  av_log(NULL, AV_LOG_WARNING,
393  "%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
394  return 0;
395  }
396  }
397  return 0;
398 }
399 
400 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
401  const uint8_t *data_end)
402 {
403  z_stream zstream;
404  unsigned char *buf;
405  unsigned buf_size;
406  int ret;
407 
408  zstream.zalloc = ff_png_zalloc;
409  zstream.zfree = ff_png_zfree;
410  zstream.opaque = NULL;
411  if (inflateInit(&zstream) != Z_OK)
412  return AVERROR_EXTERNAL;
413  zstream.next_in = (unsigned char *)data;
414  zstream.avail_in = data_end - data;
415  av_bprint_init(bp, 0, -1);
416 
417  while (zstream.avail_in > 0) {
418  av_bprint_get_buffer(bp, 1, &buf, &buf_size);
419  if (!buf_size) {
420  ret = AVERROR(ENOMEM);
421  goto fail;
422  }
423  zstream.next_out = buf;
424  zstream.avail_out = buf_size;
425  ret = inflate(&zstream, Z_PARTIAL_FLUSH);
426  if (ret != Z_OK && ret != Z_STREAM_END) {
427  ret = AVERROR_EXTERNAL;
428  goto fail;
429  }
430  bp->len += zstream.next_out - buf;
431  if (ret == Z_STREAM_END)
432  break;
433  }
434  inflateEnd(&zstream);
435  bp->str[bp->len] = 0;
436  return 0;
437 
438 fail:
439  inflateEnd(&zstream);
440  av_bprint_finalize(bp, NULL);
441  return ret;
442 }
443 
444 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
445 {
446  size_t extra = 0, i;
447  uint8_t *out, *q;
448 
449  for (i = 0; i < size_in; i++)
450  extra += in[i] >= 0x80;
451  if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
452  return NULL;
453  q = out = av_malloc(size_in + extra + 1);
454  if (!out)
455  return NULL;
456  for (i = 0; i < size_in; i++) {
457  if (in[i] >= 0x80) {
458  *(q++) = 0xC0 | (in[i] >> 6);
459  *(q++) = 0x80 | (in[i] & 0x3F);
460  } else {
461  *(q++) = in[i];
462  }
463  }
464  *(q++) = 0;
465  return out;
466 }
467 
468 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
469  AVDictionary **dict)
470 {
471  int ret, method;
472  const uint8_t *data = s->gb.buffer;
473  const uint8_t *data_end = data + length;
474  const uint8_t *keyword = data;
475  const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
476  uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
477  unsigned text_len;
478  AVBPrint bp;
479 
480  if (!keyword_end)
481  return AVERROR_INVALIDDATA;
482  data = keyword_end + 1;
483 
484  if (compressed) {
485  if (data == data_end)
486  return AVERROR_INVALIDDATA;
487  method = *(data++);
488  if (method)
489  return AVERROR_INVALIDDATA;
490  if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
491  return ret;
492  text_len = bp.len;
493  av_bprint_finalize(&bp, (char **)&text);
494  if (!text)
495  return AVERROR(ENOMEM);
496  } else {
497  text = (uint8_t *)data;
498  text_len = data_end - text;
499  }
500 
501  kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
502  txt_utf8 = iso88591_to_utf8(text, text_len);
503  if (text != data)
504  av_free(text);
505  if (!(kw_utf8 && txt_utf8)) {
506  av_free(kw_utf8);
507  av_free(txt_utf8);
508  return AVERROR(ENOMEM);
509  }
510 
511  av_dict_set(dict, kw_utf8, txt_utf8,
513  return 0;
514 }
515 
516 static int decode_frame(AVCodecContext *avctx,
517  void *data, int *got_frame,
518  AVPacket *avpkt)
519 {
520  PNGDecContext *const s = avctx->priv_data;
521  const uint8_t *buf = avpkt->data;
522  int buf_size = avpkt->size;
523  AVFrame *p;
524  AVDictionary *metadata = NULL;
525  uint32_t tag, length;
526  int64_t sig;
527  int ret;
528 
531  p = s->picture.f;
532 
533  bytestream2_init(&s->gb, buf, buf_size);
534 
535  /* check signature */
536  sig = bytestream2_get_be64(&s->gb);
537  if (sig != PNGSIG &&
538  sig != MNGSIG) {
539  av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
540  return AVERROR_INVALIDDATA;
541  }
542 
543  s->y = s->state = 0;
544 
545  /* init the zlib */
546  s->zstream.zalloc = ff_png_zalloc;
547  s->zstream.zfree = ff_png_zfree;
548  s->zstream.opaque = NULL;
549  ret = inflateInit(&s->zstream);
550  if (ret != Z_OK) {
551  av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
552  return AVERROR_EXTERNAL;
553  }
554  for (;;) {
555  if (bytestream2_get_bytes_left(&s->gb) <= 0) {
556  av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
557  if ( s->state & PNG_ALLIMAGE
559  goto exit_loop;
560  goto fail;
561  }
562 
563  length = bytestream2_get_be32(&s->gb);
564  if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
565  av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
566  goto fail;
567  }
568  tag = bytestream2_get_le32(&s->gb);
569  if (avctx->debug & FF_DEBUG_STARTCODE)
570  av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
571  (tag & 0xff),
572  ((tag >> 8) & 0xff),
573  ((tag >> 16) & 0xff),
574  ((tag >> 24) & 0xff), length);
575  switch (tag) {
576  case MKTAG('I', 'H', 'D', 'R'):
577  if (length != 13)
578  goto fail;
579  s->width = bytestream2_get_be32(&s->gb);
580  s->height = bytestream2_get_be32(&s->gb);
581  if (av_image_check_size(s->width, s->height, 0, avctx)) {
582  s->width = s->height = 0;
583  av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
584  goto fail;
585  }
586  s->bit_depth = bytestream2_get_byte(&s->gb);
587  s->color_type = bytestream2_get_byte(&s->gb);
588  s->compression_type = bytestream2_get_byte(&s->gb);
589  s->filter_type = bytestream2_get_byte(&s->gb);
590  s->interlace_type = bytestream2_get_byte(&s->gb);
591  bytestream2_skip(&s->gb, 4); /* crc */
592  s->state |= PNG_IHDR;
593  if (avctx->debug & FF_DEBUG_PICT_INFO)
594  av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
595  "compression_type=%d filter_type=%d interlace_type=%d\n",
596  s->width, s->height, s->bit_depth, s->color_type,
598  break;
599  case MKTAG('p', 'H', 'Y', 's'):
600  if (s->state & PNG_IDAT) {
601  av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
602  goto fail;
603  }
604  avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
605  avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
606  if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
607  avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
608  bytestream2_skip(&s->gb, 1); /* unit specifier */
609  bytestream2_skip(&s->gb, 4); /* crc */
610  break;
611  case MKTAG('I', 'D', 'A', 'T'):
612  if (!(s->state & PNG_IHDR)) {
613  av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
614  goto fail;
615  }
616  if (!(s->state & PNG_IDAT)) {
617  /* init image info */
618  avctx->width = s->width;
619  avctx->height = s->height;
620 
622  s->bits_per_pixel = s->bit_depth * s->channels;
623  s->bpp = (s->bits_per_pixel + 7) >> 3;
624  s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
625 
626  if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
628  avctx->pix_fmt = AV_PIX_FMT_RGB24;
629  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
631  avctx->pix_fmt = AV_PIX_FMT_RGBA;
632  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
634  avctx->pix_fmt = AV_PIX_FMT_GRAY8;
635  } else if (s->bit_depth == 16 &&
637  avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
638  } else if (s->bit_depth == 16 &&
640  avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
641  } else if (s->bit_depth == 16 &&
643  avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
644  } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
646  avctx->pix_fmt = AV_PIX_FMT_PAL8;
647  } else if (s->bit_depth == 1) {
648  avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
649  } else if (s->bit_depth == 8 &&
651  avctx->pix_fmt = AV_PIX_FMT_Y400A;
652  } else {
653  av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
654  "and color type %d\n",
655  s->bit_depth, s->color_type);
656  goto fail;
657  }
658 
660  goto fail;
661  ff_thread_finish_setup(avctx);
662 
664  p->key_frame = 1;
666 
667  /* compute the compressed row size */
668  if (!s->interlace_type) {
669  s->crow_size = s->row_size + 1;
670  } else {
671  s->pass = 0;
673  s->bits_per_pixel,
674  s->width);
675  s->crow_size = s->pass_row_size + 1;
676  }
677  av_dlog(avctx, "row_size=%d crow_size =%d\n",
678  s->row_size, s->crow_size);
679  s->image_buf = p->data[0];
680  s->image_linesize = p->linesize[0];
681  /* copy the palette if needed */
682  if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
683  memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
684  /* empty row is used if differencing to the first row */
686  if (!s->last_row)
687  goto fail;
688  if (s->interlace_type ||
691  if (!s->tmp_row)
692  goto fail;
693  }
694  /* compressed row */
696  if (!s->buffer)
697  goto fail;
698 
699  /* we want crow_buf+1 to be 16-byte aligned */
700  s->crow_buf = s->buffer + 15;
701  s->zstream.avail_out = s->crow_size;
702  s->zstream.next_out = s->crow_buf;
703  }
704  s->state |= PNG_IDAT;
705  if (png_decode_idat(s, length) < 0)
706  goto fail;
707  bytestream2_skip(&s->gb, 4); /* crc */
708  break;
709  case MKTAG('P', 'L', 'T', 'E'):
710  {
711  int n, i, r, g, b;
712 
713  if ((length % 3) != 0 || length > 256 * 3)
714  goto skip_tag;
715  /* read the palette */
716  n = length / 3;
717  for (i = 0; i < n; i++) {
718  r = bytestream2_get_byte(&s->gb);
719  g = bytestream2_get_byte(&s->gb);
720  b = bytestream2_get_byte(&s->gb);
721  s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
722  }
723  for (; i < 256; i++)
724  s->palette[i] = (0xFFU << 24);
725  s->state |= PNG_PLTE;
726  bytestream2_skip(&s->gb, 4); /* crc */
727  }
728  break;
729  case MKTAG('t', 'R', 'N', 'S'):
730  {
731  int v, i;
732 
733  /* read the transparency. XXX: Only palette mode supported */
735  length > 256 ||
736  !(s->state & PNG_PLTE))
737  goto skip_tag;
738  for (i = 0; i < length; i++) {
739  v = bytestream2_get_byte(&s->gb);
740  s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
741  }
742  bytestream2_skip(&s->gb, 4); /* crc */
743  }
744  break;
745  case MKTAG('t', 'E', 'X', 't'):
746  if (decode_text_chunk(s, length, 0, &metadata) < 0)
747  av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
748  bytestream2_skip(&s->gb, length + 4);
749  break;
750  case MKTAG('z', 'T', 'X', 't'):
751  if (decode_text_chunk(s, length, 1, &metadata) < 0)
752  av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
753  bytestream2_skip(&s->gb, length + 4);
754  break;
755  case MKTAG('I', 'E', 'N', 'D'):
756  if (!(s->state & PNG_ALLIMAGE))
757  av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
758  if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
759  goto fail;
760  }
761  bytestream2_skip(&s->gb, 4); /* crc */
762  goto exit_loop;
763  default:
764  /* skip tag */
765 skip_tag:
766  bytestream2_skip(&s->gb, length + 4);
767  break;
768  }
769  }
770 exit_loop:
771 
772  if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
773  int i, j, k;
774  uint8_t *pd = p->data[0];
775  for (j = 0; j < s->height; j++) {
776  i = s->width / 8;
777  for (k = 7; k >= 1; k--)
778  if ((s->width&7) >= k)
779  pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
780  for (i--; i >= 0; i--) {
781  pd[8*i + 7]= pd[i] & 1;
782  pd[8*i + 6]= (pd[i]>>1) & 1;
783  pd[8*i + 5]= (pd[i]>>2) & 1;
784  pd[8*i + 4]= (pd[i]>>3) & 1;
785  pd[8*i + 3]= (pd[i]>>4) & 1;
786  pd[8*i + 2]= (pd[i]>>5) & 1;
787  pd[8*i + 1]= (pd[i]>>6) & 1;
788  pd[8*i + 0]= pd[i]>>7;
789  }
790  pd += s->image_linesize;
791  }
792  }
793  if (s->bits_per_pixel == 2){
794  int i, j;
795  uint8_t *pd = p->data[0];
796  for (j = 0; j < s->height; j++) {
797  i = s->width / 4;
799  if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
800  if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
801  if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
802  for (i--; i >= 0; i--) {
803  pd[4*i + 3]= pd[i] & 3;
804  pd[4*i + 2]= (pd[i]>>2) & 3;
805  pd[4*i + 1]= (pd[i]>>4) & 3;
806  pd[4*i + 0]= pd[i]>>6;
807  }
808  } else {
809  if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
810  if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
811  if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
812  for (i--; i >= 0; i--) {
813  pd[4*i + 3]= ( pd[i] & 3)*0x55;
814  pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
815  pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
816  pd[4*i + 0]= ( pd[i]>>6 )*0x55;
817  }
818  }
819  pd += s->image_linesize;
820  }
821  }
822  if (s->bits_per_pixel == 4){
823  int i, j;
824  uint8_t *pd = p->data[0];
825  for (j = 0; j < s->height; j++) {
826  i = s->width/2;
828  if (s->width&1) pd[2*i+0]= pd[i]>>4;
829  for (i--; i >= 0; i--) {
830  pd[2*i + 1] = pd[i] & 15;
831  pd[2*i + 0] = pd[i] >> 4;
832  }
833  } else {
834  if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
835  for (i--; i >= 0; i--) {
836  pd[2*i + 1] = (pd[i] & 15) * 0x11;
837  pd[2*i + 0] = (pd[i] >> 4) * 0x11;
838  }
839  }
840  pd += s->image_linesize;
841  }
842  }
843 
844  /* handle p-frames only if a predecessor frame is available */
845  if (s->last_picture.f->data[0]) {
846  if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
847  && s->last_picture.f->width == p->width
848  && s->last_picture.f->height== p->height
849  && s->last_picture.f->format== p->format
850  ) {
851  int i, j;
852  uint8_t *pd = p->data[0];
853  uint8_t *pd_last = s->last_picture.f->data[0];
854 
855  ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
856  for (j = 0; j < s->height; j++) {
857  for (i = 0; i < s->width * s->bpp; i++)
858  pd[i] += pd_last[i];
859  pd += s->image_linesize;
860  pd_last += s->image_linesize;
861  }
862  }
863  }
864  ff_thread_report_progress(&s->picture, INT_MAX, 0);
865 
866  av_frame_set_metadata(p, metadata);
867  metadata = NULL;
868 
869  if ((ret = av_frame_ref(data, s->picture.f)) < 0)
870  return ret;
871 
872  *got_frame = 1;
873 
874  ret = bytestream2_tell(&s->gb);
875 the_end:
876  inflateEnd(&s->zstream);
877  s->crow_buf = NULL;
878  return ret;
879 fail:
880  av_dict_free(&metadata);
881  ff_thread_report_progress(&s->picture, INT_MAX, 0);
882  ret = AVERROR_INVALIDDATA;
883  goto the_end;
884 }
885 
887 {
888  PNGDecContext *psrc = src->priv_data;
889  PNGDecContext *pdst = dst->priv_data;
890 
891  if (dst == src)
892  return 0;
893 
894  ff_thread_release_buffer(dst, &pdst->picture);
895  if (psrc->picture.f->data[0])
896  return ff_thread_ref_frame(&pdst->picture, &psrc->picture);
897 
898  return 0;
899 }
900 
902 {
903  PNGDecContext *s = avctx->priv_data;
904 
905  s->avctx = avctx;
907  s->picture.f = av_frame_alloc();
908  if (!s->last_picture.f || !s->picture.f)
909  return AVERROR(ENOMEM);
910 
911  if (!avctx->internal->is_copy) {
912  avctx->internal->allocate_progress = 1;
913  ff_pngdsp_init(&s->dsp);
914  }
915 
916  return 0;
917 }
918 
920 {
921  PNGDecContext *s = avctx->priv_data;
922 
925  ff_thread_release_buffer(avctx, &s->picture);
926  av_frame_free(&s->picture.f);
927  av_freep(&s->buffer);
928  s->buffer_size = 0;
929  av_freep(&s->last_row);
930  s->last_row_size = 0;
931  av_freep(&s->tmp_row);
932  s->tmp_row_size = 0;
933 
934  return 0;
935 }
936 
938  .name = "png",
939  .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
940  .type = AVMEDIA_TYPE_VIDEO,
941  .id = AV_CODEC_ID_PNG,
942  .priv_data_size = sizeof(PNGDecContext),
943  .init = png_dec_init,
944  .close = png_dec_end,
945  .decode = decode_frame,
947  .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
948  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
949 };