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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 
160 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
161 {
162  int i;
163  for (i = 0; i < w; i++) {
164  int a, b, c, p, pa, pb, pc;
165 
166  a = dst[i - bpp];
167  b = top[i];
168  c = top[i - bpp];
169 
170  p = b - c;
171  pc = a - c;
172 
173  pa = abs(p);
174  pb = abs(pc);
175  pc = abs(p + pc);
176 
177  if (pa <= pb && pa <= pc)
178  p = a;
179  else if (pb <= pc)
180  p = b;
181  else
182  p = c;
183  dst[i] = p + src[i];
184  }
185 }
186 
187 #define UNROLL1(bpp, op) {\
188  r = dst[0];\
189  if(bpp >= 2) g = dst[1];\
190  if(bpp >= 3) b = dst[2];\
191  if(bpp >= 4) a = dst[3];\
192  for(; i <= size - bpp; i+=bpp) {\
193  dst[i+0] = r = op(r, src[i+0], last[i+0]);\
194  if(bpp == 1) continue;\
195  dst[i+1] = g = op(g, src[i+1], last[i+1]);\
196  if(bpp == 2) continue;\
197  dst[i+2] = b = op(b, src[i+2], last[i+2]);\
198  if(bpp == 3) continue;\
199  dst[i+3] = a = op(a, src[i+3], last[i+3]);\
200  }\
201 }
202 
203 #define UNROLL_FILTER(op)\
204  if(bpp == 1) UNROLL1(1, op)\
205  else if(bpp == 2) UNROLL1(2, op)\
206  else if(bpp == 3) UNROLL1(3, op)\
207  else if(bpp == 4) UNROLL1(4, op)\
208  for (; i < size; i++) {\
209  dst[i] = op(dst[i-bpp], src[i], last[i]);\
210  }\
211 
212 /* NOTE: 'dst' can be equal to 'last' */
213 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
214  uint8_t *src, uint8_t *last, int size, int bpp)
215 {
216  int i, p, r, g, b, a;
217 
218  switch (filter_type) {
220  memcpy(dst, src, size);
221  break;
223  for (i = 0; i < bpp; i++) {
224  dst[i] = src[i];
225  }
226  if (bpp == 4) {
227  p = *(int*)dst;
228  for (; i < size; i += bpp) {
229  int s = *(int*)(src + i);
230  p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
231  *(int*)(dst + i) = p;
232  }
233  } else {
234 #define OP_SUB(x,s,l) x+s
236  }
237  break;
238  case PNG_FILTER_VALUE_UP:
239  dsp->add_bytes_l2(dst, src, last, size);
240  break;
242  for (i = 0; i < bpp; i++) {
243  p = (last[i] >> 1);
244  dst[i] = p + src[i];
245  }
246 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
248  break;
250  for (i = 0; i < bpp; i++) {
251  p = last[i];
252  dst[i] = p + src[i];
253  }
254  if (bpp > 2 && size > 4) {
255  // would write off the end of the array if we let it process the last pixel with bpp=3
256  int w = bpp == 4 ? size : size - 3;
257  dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
258  i = w;
259  }
260  ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
261  break;
262  }
263 }
264 
265 /* This used to be called "deloco" in FFmpeg
266  * and is actually an inverse reversible colorspace transformation */
267 #define YUV2RGB(NAME, TYPE) \
268 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
269 { \
270  int i; \
271  for (i = 0; i < size; i += 3 + alpha) { \
272  int g = dst [i+1]; \
273  dst[i+0] += g; \
274  dst[i+2] += g; \
275  } \
276 }
277 
278 YUV2RGB(rgb8, uint8_t)
279 YUV2RGB(rgb16, uint16_t)
280 
281 /* process exactly one decompressed row */
283 {
284  uint8_t *ptr, *last_row;
285  int got_line;
286 
287  if (!s->interlace_type) {
288  ptr = s->image_buf + s->image_linesize * s->y;
289  if (s->y == 0)
290  last_row = s->last_row;
291  else
292  last_row = ptr - s->image_linesize;
293 
294  png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
295  last_row, s->row_size, s->bpp);
296  /* loco lags by 1 row so that it doesn't interfere with top prediction */
297  if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
298  if (s->bit_depth == 16) {
299  deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
300  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
301  } else {
302  deloco_rgb8(ptr - s->image_linesize, s->row_size,
303  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
304  }
305  }
306  s->y++;
307  if (s->y == s->height) {
308  s->state |= PNG_ALLIMAGE;
309  if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
310  if (s->bit_depth == 16) {
311  deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
312  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
313  } else {
314  deloco_rgb8(ptr, s->row_size,
315  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
316  }
317  }
318  }
319  } else {
320  got_line = 0;
321  for (;;) {
322  ptr = s->image_buf + s->image_linesize * s->y;
323  if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
324  /* if we already read one row, it is time to stop to
325  wait for the next one */
326  if (got_line)
327  break;
328  png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
329  s->last_row, s->pass_row_size, s->bpp);
330  FFSWAP(uint8_t*, s->last_row, s->tmp_row);
331  FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
332  got_line = 1;
333  }
334  if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
335  png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
336  s->color_type, s->last_row);
337  }
338  s->y++;
339  if (s->y == s->height) {
340  memset(s->last_row, 0, s->row_size);
341  for (;;) {
342  if (s->pass == NB_PASSES - 1) {
343  s->state |= PNG_ALLIMAGE;
344  goto the_end;
345  } else {
346  s->pass++;
347  s->y = 0;
348  s->pass_row_size = ff_png_pass_row_size(s->pass,
349  s->bits_per_pixel,
350  s->width);
351  s->crow_size = s->pass_row_size + 1;
352  if (s->pass_row_size != 0)
353  break;
354  /* skip pass if empty row */
355  }
356  }
357  }
358  }
359  the_end: ;
360  }
361 }
362 
364 {
365  int ret;
366  s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
367  s->zstream.next_in = (unsigned char *)s->gb.buffer;
368  bytestream2_skip(&s->gb, length);
369 
370  /* decode one line if possible */
371  while (s->zstream.avail_in > 0) {
372  ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
373  if (ret != Z_OK && ret != Z_STREAM_END) {
374  av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
375  return AVERROR_EXTERNAL;
376  }
377  if (s->zstream.avail_out == 0) {
378  if (!(s->state & PNG_ALLIMAGE)) {
379  png_handle_row(s);
380  }
381  s->zstream.avail_out = s->crow_size;
382  s->zstream.next_out = s->crow_buf;
383  }
384  if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
385  av_log(NULL, AV_LOG_WARNING, "%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
386  return 0;
387  }
388  }
389  return 0;
390 }
391 
392 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
393  const uint8_t *data_end)
394 {
395  z_stream zstream;
396  unsigned char *buf;
397  unsigned buf_size;
398  int ret;
399 
400  zstream.zalloc = ff_png_zalloc;
401  zstream.zfree = ff_png_zfree;
402  zstream.opaque = NULL;
403  if (inflateInit(&zstream) != Z_OK)
404  return AVERROR_EXTERNAL;
405  zstream.next_in = (unsigned char *)data;
406  zstream.avail_in = data_end - data;
407  av_bprint_init(bp, 0, -1);
408 
409  while (zstream.avail_in > 0) {
410  av_bprint_get_buffer(bp, 1, &buf, &buf_size);
411  if (!buf_size) {
412  ret = AVERROR(ENOMEM);
413  goto fail;
414  }
415  zstream.next_out = buf;
416  zstream.avail_out = buf_size;
417  ret = inflate(&zstream, Z_PARTIAL_FLUSH);
418  if (ret != Z_OK && ret != Z_STREAM_END) {
419  ret = AVERROR_EXTERNAL;
420  goto fail;
421  }
422  bp->len += zstream.next_out - buf;
423  if (ret == Z_STREAM_END)
424  break;
425  }
426  inflateEnd(&zstream);
427  bp->str[bp->len] = 0;
428  return 0;
429 
430 fail:
431  inflateEnd(&zstream);
432  av_bprint_finalize(bp, NULL);
433  return ret;
434 }
435 
436 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
437 {
438  size_t extra = 0, i;
439  uint8_t *out, *q;
440 
441  for (i = 0; i < size_in; i++)
442  extra += in[i] >= 0x80;
443  if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
444  return NULL;
445  q = out = av_malloc(size_in + extra + 1);
446  if (!out)
447  return NULL;
448  for (i = 0; i < size_in; i++) {
449  if (in[i] >= 0x80) {
450  *(q++) = 0xC0 | (in[i] >> 6);
451  *(q++) = 0x80 | (in[i] & 0x3F);
452  } else {
453  *(q++) = in[i];
454  }
455  }
456  *(q++) = 0;
457  return out;
458 }
459 
460 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
461  AVDictionary **dict)
462 {
463  int ret, method;
464  const uint8_t *data = s->gb.buffer;
465  const uint8_t *data_end = data + length;
466  const uint8_t *keyword = data;
467  const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
468  uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
469  unsigned text_len;
470  AVBPrint bp;
471 
472  if (!keyword_end)
473  return AVERROR_INVALIDDATA;
474  data = keyword_end + 1;
475 
476  if (compressed) {
477  if (data == data_end)
478  return AVERROR_INVALIDDATA;
479  method = *(data++);
480  if (method)
481  return AVERROR_INVALIDDATA;
482  if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
483  return ret;
484  text_len = bp.len;
485  av_bprint_finalize(&bp, (char **)&text);
486  if (!text)
487  return AVERROR(ENOMEM);
488  } else {
489  text = (uint8_t *)data;
490  text_len = data_end - text;
491  }
492 
493  kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
494  txt_utf8 = iso88591_to_utf8(text, text_len);
495  if (text != data)
496  av_free(text);
497  if (!(kw_utf8 && txt_utf8)) {
498  av_free(kw_utf8);
499  av_free(txt_utf8);
500  return AVERROR(ENOMEM);
501  }
502 
503  av_dict_set(dict, kw_utf8, txt_utf8,
505  return 0;
506 }
507 
508 static int decode_frame(AVCodecContext *avctx,
509  void *data, int *got_frame,
510  AVPacket *avpkt)
511 {
512  PNGDecContext * const s = avctx->priv_data;
513  const uint8_t *buf = avpkt->data;
514  int buf_size = avpkt->size;
515  AVFrame *p;
516  AVDictionary *metadata = NULL;
517  uint32_t tag, length;
518  int64_t sig;
519  int ret;
520 
523  p = s->picture.f;
524 
525  bytestream2_init(&s->gb, buf, buf_size);
526 
527  /* check signature */
528  sig = bytestream2_get_be64(&s->gb);
529  if (sig != PNGSIG &&
530  sig != MNGSIG) {
531  av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
532  return AVERROR_INVALIDDATA;
533  }
534 
535  s->y = s->state = 0;
536 
537  /* init the zlib */
538  s->zstream.zalloc = ff_png_zalloc;
539  s->zstream.zfree = ff_png_zfree;
540  s->zstream.opaque = NULL;
541  ret = inflateInit(&s->zstream);
542  if (ret != Z_OK) {
543  av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
544  return AVERROR_EXTERNAL;
545  }
546  for (;;) {
547  if (bytestream2_get_bytes_left(&s->gb) <= 0) {
548  av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
549  goto fail;
550  }
551 
552  length = bytestream2_get_be32(&s->gb);
553  if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
554  av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
555  goto fail;
556  }
557  tag = bytestream2_get_le32(&s->gb);
558  if (avctx->debug & FF_DEBUG_STARTCODE)
559  av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
560  (tag & 0xff),
561  ((tag >> 8) & 0xff),
562  ((tag >> 16) & 0xff),
563  ((tag >> 24) & 0xff), length);
564  switch (tag) {
565  case MKTAG('I', 'H', 'D', 'R'):
566  if (length != 13)
567  goto fail;
568  s->width = bytestream2_get_be32(&s->gb);
569  s->height = bytestream2_get_be32(&s->gb);
570  if (av_image_check_size(s->width, s->height, 0, avctx)) {
571  s->width = s->height = 0;
572  av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
573  goto fail;
574  }
575  s->bit_depth = bytestream2_get_byte(&s->gb);
576  s->color_type = bytestream2_get_byte(&s->gb);
577  s->compression_type = bytestream2_get_byte(&s->gb);
578  s->filter_type = bytestream2_get_byte(&s->gb);
579  s->interlace_type = bytestream2_get_byte(&s->gb);
580  bytestream2_skip(&s->gb, 4); /* crc */
581  s->state |= PNG_IHDR;
582  if (avctx->debug & FF_DEBUG_PICT_INFO)
583  av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
584  "compression_type=%d filter_type=%d interlace_type=%d\n",
585  s->width, s->height, s->bit_depth, s->color_type,
587  break;
588  case MKTAG('p', 'H', 'Y', 's'):
589  if (s->state & PNG_IDAT) {
590  av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
591  goto fail;
592  }
593  avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
594  avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
595  if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
596  avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
597  bytestream2_skip(&s->gb, 1); /* unit specifier */
598  bytestream2_skip(&s->gb, 4); /* crc */
599  break;
600  case MKTAG('I', 'D', 'A', 'T'):
601  if (!(s->state & PNG_IHDR)) {
602  av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
603  goto fail;
604  }
605  if (!(s->state & PNG_IDAT)) {
606  /* init image info */
607  avctx->width = s->width;
608  avctx->height = s->height;
609 
611  s->bits_per_pixel = s->bit_depth * s->channels;
612  s->bpp = (s->bits_per_pixel + 7) >> 3;
613  s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
614 
615  if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
617  avctx->pix_fmt = AV_PIX_FMT_RGB24;
618  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
620  avctx->pix_fmt = AV_PIX_FMT_RGBA;
621  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
623  avctx->pix_fmt = AV_PIX_FMT_GRAY8;
624  } else if (s->bit_depth == 16 &&
626  avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
627  } else if (s->bit_depth == 16 &&
629  avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
630  } else if (s->bit_depth == 16 &&
632  avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
633  } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
635  avctx->pix_fmt = AV_PIX_FMT_PAL8;
636  } else if (s->bit_depth == 1) {
637  avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
638  } else if (s->bit_depth == 8 &&
640  avctx->pix_fmt = AV_PIX_FMT_Y400A;
641  } else {
642  av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
643  "and color type %d\n",
644  s->bit_depth, s->color_type);
645  goto fail;
646  }
647 
649  goto fail;
650  ff_thread_finish_setup(avctx);
651 
653  p->key_frame = 1;
655 
656  /* compute the compressed row size */
657  if (!s->interlace_type) {
658  s->crow_size = s->row_size + 1;
659  } else {
660  s->pass = 0;
662  s->bits_per_pixel,
663  s->width);
664  s->crow_size = s->pass_row_size + 1;
665  }
666  av_dlog(avctx, "row_size=%d crow_size =%d\n",
667  s->row_size, s->crow_size);
668  s->image_buf = p->data[0];
669  s->image_linesize = p->linesize[0];
670  /* copy the palette if needed */
671  if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
672  memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
673  /* empty row is used if differencing to the first row */
675  if (!s->last_row)
676  goto fail;
677  if (s->interlace_type ||
680  if (!s->tmp_row)
681  goto fail;
682  }
683  /* compressed row */
685  if (!s->buffer)
686  goto fail;
687 
688  /* we want crow_buf+1 to be 16-byte aligned */
689  s->crow_buf = s->buffer + 15;
690  s->zstream.avail_out = s->crow_size;
691  s->zstream.next_out = s->crow_buf;
692  }
693  s->state |= PNG_IDAT;
694  if (png_decode_idat(s, length) < 0)
695  goto fail;
696  bytestream2_skip(&s->gb, 4); /* crc */
697  break;
698  case MKTAG('P', 'L', 'T', 'E'):
699  {
700  int n, i, r, g, b;
701 
702  if ((length % 3) != 0 || length > 256 * 3)
703  goto skip_tag;
704  /* read the palette */
705  n = length / 3;
706  for (i = 0; i < n; i++) {
707  r = bytestream2_get_byte(&s->gb);
708  g = bytestream2_get_byte(&s->gb);
709  b = bytestream2_get_byte(&s->gb);
710  s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
711  }
712  for (; i < 256; i++) {
713  s->palette[i] = (0xFFU << 24);
714  }
715  s->state |= PNG_PLTE;
716  bytestream2_skip(&s->gb, 4); /* crc */
717  }
718  break;
719  case MKTAG('t', 'R', 'N', 'S'):
720  {
721  int v, i;
722 
723  /* read the transparency. XXX: Only palette mode supported */
725  length > 256 ||
726  !(s->state & PNG_PLTE))
727  goto skip_tag;
728  for (i = 0; i < length; i++) {
729  v = bytestream2_get_byte(&s->gb);
730  s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
731  }
732  bytestream2_skip(&s->gb, 4); /* crc */
733  }
734  break;
735  case MKTAG('t', 'E', 'X', 't'):
736  if (decode_text_chunk(s, length, 0, &metadata) < 0)
737  av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
738  bytestream2_skip(&s->gb, length + 4);
739  break;
740  case MKTAG('z', 'T', 'X', 't'):
741  if (decode_text_chunk(s, length, 1, &metadata) < 0)
742  av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
743  bytestream2_skip(&s->gb, length + 4);
744  break;
745  case MKTAG('I', 'E', 'N', 'D'):
746  if (!(s->state & PNG_ALLIMAGE))
747  av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
748  if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
749  goto fail;
750  }
751  bytestream2_skip(&s->gb, 4); /* crc */
752  goto exit_loop;
753  default:
754  /* skip tag */
755  skip_tag:
756  bytestream2_skip(&s->gb, length + 4);
757  break;
758  }
759  }
760  exit_loop:
761 
762  if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
763  int i, j, k;
764  uint8_t *pd = p->data[0];
765  for (j = 0; j < s->height; j++) {
766  i = s->width / 8;
767  for (k = 7; k >= 1; k--)
768  if ((s->width&7) >= k)
769  pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
770  for (i--; i >= 0; i--) {
771  pd[8*i + 7]= pd[i] & 1;
772  pd[8*i + 6]= (pd[i]>>1) & 1;
773  pd[8*i + 5]= (pd[i]>>2) & 1;
774  pd[8*i + 4]= (pd[i]>>3) & 1;
775  pd[8*i + 3]= (pd[i]>>4) & 1;
776  pd[8*i + 2]= (pd[i]>>5) & 1;
777  pd[8*i + 1]= (pd[i]>>6) & 1;
778  pd[8*i + 0]= pd[i]>>7;
779  }
780  pd += s->image_linesize;
781  }
782  }
783  if (s->bits_per_pixel == 2){
784  int i, j;
785  uint8_t *pd = p->data[0];
786  for (j = 0; j < s->height; j++) {
787  i = s->width / 4;
789  if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
790  if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
791  if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
792  for (i--; i >= 0; i--) {
793  pd[4*i + 3]= pd[i] & 3;
794  pd[4*i + 2]= (pd[i]>>2) & 3;
795  pd[4*i + 1]= (pd[i]>>4) & 3;
796  pd[4*i + 0]= pd[i]>>6;
797  }
798  } else {
799  if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
800  if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
801  if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
802  for (i--; i >= 0; i--) {
803  pd[4*i + 3]= ( pd[i] & 3)*0x55;
804  pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
805  pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
806  pd[4*i + 0]= ( pd[i]>>6 )*0x55;
807  }
808  }
809  pd += s->image_linesize;
810  }
811  }
812  if (s->bits_per_pixel == 4){
813  int i, j;
814  uint8_t *pd = p->data[0];
815  for (j = 0; j < s->height; j++) {
816  i = s->width/2;
818  if (s->width&1) pd[2*i+0]= pd[i]>>4;
819  for (i--; i >= 0; i--) {
820  pd[2*i + 1] = pd[i] & 15;
821  pd[2*i + 0] = pd[i] >> 4;
822  }
823  } else {
824  if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
825  for (i--; i >= 0; i--) {
826  pd[2*i + 1] = (pd[i] & 15) * 0x11;
827  pd[2*i + 0] = (pd[i] >> 4) * 0x11;
828  }
829  }
830  pd += s->image_linesize;
831  }
832  }
833 
834  /* handle p-frames only if a predecessor frame is available */
835  if (s->last_picture.f->data[0]) {
836  if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
837  && s->last_picture.f->width == p->width
838  && s->last_picture.f->height== p->height
839  && s->last_picture.f->format== p->format
840  ) {
841  int i, j;
842  uint8_t *pd = p->data[0];
843  uint8_t *pd_last = s->last_picture.f->data[0];
844 
845  ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
846  for (j = 0; j < s->height; j++) {
847  for (i = 0; i < s->width * s->bpp; i++) {
848  pd[i] += pd_last[i];
849  }
850  pd += s->image_linesize;
851  pd_last += s->image_linesize;
852  }
853  }
854  }
855  ff_thread_report_progress(&s->picture, INT_MAX, 0);
856 
857  av_frame_set_metadata(p, metadata);
858  metadata = NULL;
859 
860  if ((ret = av_frame_ref(data, s->picture.f)) < 0)
861  return ret;
862 
863  *got_frame = 1;
864 
865  ret = bytestream2_tell(&s->gb);
866  the_end:
867  inflateEnd(&s->zstream);
868  s->crow_buf = NULL;
869  return ret;
870  fail:
871  av_dict_free(&metadata);
872  ff_thread_report_progress(&s->picture, INT_MAX, 0);
873  ret = AVERROR_INVALIDDATA;
874  goto the_end;
875 }
876 
878 {
879  PNGDecContext *psrc = src->priv_data;
880  PNGDecContext *pdst = dst->priv_data;
881 
882  if (dst == src)
883  return 0;
884 
885  ff_thread_release_buffer(dst, &pdst->picture);
886  if (psrc->picture.f->data[0])
887  return ff_thread_ref_frame(&pdst->picture, &psrc->picture);
888 
889  return 0;
890 }
891 
893 {
894  PNGDecContext *s = avctx->priv_data;
895 
896  s->avctx = avctx;
898  s->picture.f = av_frame_alloc();
899  if (!s->last_picture.f || !s->picture.f)
900  return AVERROR(ENOMEM);
901 
902  if (!avctx->internal->is_copy) {
903  avctx->internal->allocate_progress = 1;
904  ff_pngdsp_init(&s->dsp);
905  }
906 
907  return 0;
908 }
909 
911 {
912  PNGDecContext *s = avctx->priv_data;
913 
916  ff_thread_release_buffer(avctx, &s->picture);
917  av_frame_free(&s->picture.f);
918  av_freep(&s->buffer);
919  s->buffer_size = 0;
920  av_freep(&s->last_row);
921  s->last_row_size = 0;
922  av_freep(&s->tmp_row);
923  s->tmp_row_size = 0;
924 
925  return 0;
926 }
927 
929  .name = "png",
930  .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
931  .type = AVMEDIA_TYPE_VIDEO,
932  .id = AV_CODEC_ID_PNG,
933  .priv_data_size = sizeof(PNGDecContext),
934  .init = png_dec_init,
935  .close = png_dec_end,
936  .decode = decode_frame,
938  .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
939  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
940 };