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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 {
36  PNGDSPContext dsp;
37  AVCodecContext *avctx;
38 
39  GetByteContext gb;
40  ThreadFrame last_picture;
41  ThreadFrame picture;
42 
43  int state;
44  int width, height;
45  int bit_depth;
46  int color_type;
47  int compression_type;
48  int interlace_type;
49  int filter_type;
50  int channels;
51  int bits_per_pixel;
52  int bpp;
53 
54  uint8_t *image_buf;
55  int image_linesize;
56  uint32_t palette[256];
57  uint8_t *crow_buf;
58  uint8_t *last_row;
59  unsigned int last_row_size;
60  uint8_t *tmp_row;
61  unsigned int tmp_row_size;
62  uint8_t *buffer;
63  int buffer_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;
70 } PNGDecContext;
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 */
78 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
79  0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
80 };
81 
82 /* Mask to determine which pixels to overwrite while displaying */
83 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
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,
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  { \
190  r = dst[0]; \
191  if (bpp >= 2) \
192  g = dst[1]; \
193  if (bpp >= 3) \
194  b = dst[2]; \
195  if (bpp >= 4) \
196  a = dst[3]; \
197  for (; i <= size - bpp; i += bpp) { \
198  dst[i + 0] = r = op(r, src[i + 0], last[i + 0]); \
199  if (bpp == 1) \
200  continue; \
201  dst[i + 1] = g = op(g, src[i + 1], last[i + 1]); \
202  if (bpp == 2) \
203  continue; \
204  dst[i + 2] = b = op(b, src[i + 2], last[i + 2]); \
205  if (bpp == 3) \
206  continue; \
207  dst[i + 3] = a = op(a, src[i + 3], last[i + 3]); \
208  } \
209  }
210 
211 #define UNROLL_FILTER(op) \
212  if (bpp == 1) { \
213  UNROLL1(1, op) \
214  } else if (bpp == 2) { \
215  UNROLL1(2, op) \
216  } else if (bpp == 3) { \
217  UNROLL1(3, op) \
218  } else if (bpp == 4) { \
219  UNROLL1(4, op) \
220  } \
221  for (; i < size; i++) { \
222  dst[i] = op(dst[i - bpp], src[i], last[i]); \
223  }
224 
225 /* NOTE: 'dst' can be equal to 'last' */
226 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
227  uint8_t *src, uint8_t *last, int size, int bpp)
228 {
229  int i, p, r, g, b, a;
230 
231  switch (filter_type) {
232  case PNG_FILTER_VALUE_NONE:
233  memcpy(dst, src, size);
234  break;
235  case PNG_FILTER_VALUE_SUB:
236  for (i = 0; i < bpp; i++)
237  dst[i] = src[i];
238  if (bpp == 4) {
239  p = *(int *)dst;
240  for (; i < size; i += bpp) {
241  unsigned s = *(int *)(src + i);
242  p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
243  *(int *)(dst + i) = p;
244  }
245  } else {
246 #define OP_SUB(x, s, l) ((x) + (s))
247  UNROLL_FILTER(OP_SUB);
248  }
249  break;
250  case PNG_FILTER_VALUE_UP:
251  dsp->add_bytes_l2(dst, src, last, size);
252  break;
253  case PNG_FILTER_VALUE_AVG:
254  for (i = 0; i < bpp; i++) {
255  p = (last[i] >> 1);
256  dst[i] = p + src[i];
257  }
258 #define OP_AVG(x, s, l) (((((x) + (l)) >> 1) + (s)) & 0xff)
259  UNROLL_FILTER(OP_AVG);
260  break;
261  case PNG_FILTER_VALUE_PAETH:
262  for (i = 0; i < bpp; i++) {
263  p = last[i];
264  dst[i] = p + src[i];
265  }
266  if (bpp > 2 && size > 4) {
267  /* would write off the end of the array if we let it process
268  * the last pixel with bpp=3 */
269  int w = bpp == 4 ? size : size - 3;
270  dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
271  i = w;
272  }
273  ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
274  break;
275  }
276 }
277 
278 /* This used to be called "deloco" in FFmpeg
279  * and is actually an inverse reversible colorspace transformation */
280 #define YUV2RGB(NAME, TYPE) \
281 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
282 { \
283  int i; \
284  for (i = 0; i < size; i += 3 + alpha) { \
285  int g = dst [i + 1]; \
286  dst[i + 0] += g; \
287  dst[i + 2] += g; \
288  } \
289 }
290 
291 YUV2RGB(rgb8, uint8_t)
292 YUV2RGB(rgb16, uint16_t)
293 
294 /* process exactly one decompressed row */
295 static void png_handle_row(PNGDecContext *s)
296 {
297  uint8_t *ptr, *last_row;
298  int got_line;
299 
300  if (!s->interlace_type) {
301  ptr = s->image_buf + s->image_linesize * s->y;
302  if (s->y == 0)
303  last_row = s->last_row;
304  else
305  last_row = ptr - s->image_linesize;
306 
307  png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
308  last_row, s->row_size, s->bpp);
309  /* loco lags by 1 row so that it doesn't interfere with top prediction */
310  if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
311  if (s->bit_depth == 16) {
312  deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
313  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
314  } else {
315  deloco_rgb8(ptr - s->image_linesize, s->row_size,
316  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
317  }
318  }
319  s->y++;
320  if (s->y == s->height) {
321  s->state |= PNG_ALLIMAGE;
322  if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
323  if (s->bit_depth == 16) {
324  deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
325  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
326  } else {
327  deloco_rgb8(ptr, s->row_size,
328  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
329  }
330  }
331  }
332  } else {
333  got_line = 0;
334  for (;;) {
335  ptr = s->image_buf + s->image_linesize * s->y;
336  if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
337  /* if we already read one row, it is time to stop to
338  * wait for the next one */
339  if (got_line)
340  break;
341  png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
342  s->last_row, s->pass_row_size, s->bpp);
343  FFSWAP(uint8_t *, s->last_row, s->tmp_row);
344  FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
345  got_line = 1;
346  }
347  if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
348  png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
349  s->color_type, s->last_row);
350  }
351  s->y++;
352  if (s->y == s->height) {
353  memset(s->last_row, 0, s->row_size);
354  for (;;) {
355  if (s->pass == NB_PASSES - 1) {
356  s->state |= PNG_ALLIMAGE;
357  goto the_end;
358  } else {
359  s->pass++;
360  s->y = 0;
361  s->pass_row_size = ff_png_pass_row_size(s->pass,
362  s->bits_per_pixel,
363  s->width);
364  s->crow_size = s->pass_row_size + 1;
365  if (s->pass_row_size != 0)
366  break;
367  /* skip pass if empty row */
368  }
369  }
370  }
371  }
372 the_end:;
373  }
374 }
375 
376 static int png_decode_idat(PNGDecContext *s, int length)
377 {
378  int ret;
379  s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
380  s->zstream.next_in = (unsigned char *)s->gb.buffer;
381  bytestream2_skip(&s->gb, length);
382 
383  /* decode one line if possible */
384  while (s->zstream.avail_in > 0) {
385  ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
386  if (ret != Z_OK && ret != Z_STREAM_END) {
387  av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
388  return AVERROR_EXTERNAL;
389  }
390  if (s->zstream.avail_out == 0) {
391  if (!(s->state & PNG_ALLIMAGE)) {
392  png_handle_row(s);
393  }
394  s->zstream.avail_out = s->crow_size;
395  s->zstream.next_out = s->crow_buf;
396  }
397  if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
398  av_log(NULL, AV_LOG_WARNING,
399  "%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
400  return 0;
401  }
402  }
403  return 0;
404 }
405 
406 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
407  const uint8_t *data_end)
408 {
409  z_stream zstream;
410  unsigned char *buf;
411  unsigned buf_size;
412  int ret;
413 
414  zstream.zalloc = ff_png_zalloc;
415  zstream.zfree = ff_png_zfree;
416  zstream.opaque = NULL;
417  if (inflateInit(&zstream) != Z_OK)
418  return AVERROR_EXTERNAL;
419  zstream.next_in = (unsigned char *)data;
420  zstream.avail_in = data_end - data;
421  av_bprint_init(bp, 0, -1);
422 
423  while (zstream.avail_in > 0) {
424  av_bprint_get_buffer(bp, 1, &buf, &buf_size);
425  if (!buf_size) {
426  ret = AVERROR(ENOMEM);
427  goto fail;
428  }
429  zstream.next_out = buf;
430  zstream.avail_out = buf_size;
431  ret = inflate(&zstream, Z_PARTIAL_FLUSH);
432  if (ret != Z_OK && ret != Z_STREAM_END) {
433  ret = AVERROR_EXTERNAL;
434  goto fail;
435  }
436  bp->len += zstream.next_out - buf;
437  if (ret == Z_STREAM_END)
438  break;
439  }
440  inflateEnd(&zstream);
441  bp->str[bp->len] = 0;
442  return 0;
443 
444 fail:
445  inflateEnd(&zstream);
446  av_bprint_finalize(bp, NULL);
447  return ret;
448 }
449 
450 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
451 {
452  size_t extra = 0, i;
453  uint8_t *out, *q;
454 
455  for (i = 0; i < size_in; i++)
456  extra += in[i] >= 0x80;
457  if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
458  return NULL;
459  q = out = av_malloc(size_in + extra + 1);
460  if (!out)
461  return NULL;
462  for (i = 0; i < size_in; i++) {
463  if (in[i] >= 0x80) {
464  *(q++) = 0xC0 | (in[i] >> 6);
465  *(q++) = 0x80 | (in[i] & 0x3F);
466  } else {
467  *(q++) = in[i];
468  }
469  }
470  *(q++) = 0;
471  return out;
472 }
473 
474 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
475  AVDictionary **dict)
476 {
477  int ret, method;
478  const uint8_t *data = s->gb.buffer;
479  const uint8_t *data_end = data + length;
480  const uint8_t *keyword = data;
481  const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
482  uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
483  unsigned text_len;
484  AVBPrint bp;
485 
486  if (!keyword_end)
487  return AVERROR_INVALIDDATA;
488  data = keyword_end + 1;
489 
490  if (compressed) {
491  if (data == data_end)
492  return AVERROR_INVALIDDATA;
493  method = *(data++);
494  if (method)
495  return AVERROR_INVALIDDATA;
496  if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
497  return ret;
498  text_len = bp.len;
499  av_bprint_finalize(&bp, (char **)&text);
500  if (!text)
501  return AVERROR(ENOMEM);
502  } else {
503  text = (uint8_t *)data;
504  text_len = data_end - text;
505  }
506 
507  kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
508  txt_utf8 = iso88591_to_utf8(text, text_len);
509  if (text != data)
510  av_free(text);
511  if (!(kw_utf8 && txt_utf8)) {
512  av_free(kw_utf8);
513  av_free(txt_utf8);
514  return AVERROR(ENOMEM);
515  }
516 
517  av_dict_set(dict, kw_utf8, txt_utf8,
518  AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
519  return 0;
520 }
521 
522 static int decode_frame(AVCodecContext *avctx,
523  void *data, int *got_frame,
524  AVPacket *avpkt)
525 {
526  PNGDecContext *const s = avctx->priv_data;
527  const uint8_t *buf = avpkt->data;
528  int buf_size = avpkt->size;
529  AVFrame *p;
530  AVDictionary *metadata = NULL;
531  uint32_t tag, length;
532  int64_t sig;
533  int ret;
534 
535  ff_thread_release_buffer(avctx, &s->last_picture);
536  FFSWAP(ThreadFrame, s->picture, s->last_picture);
537  p = s->picture.f;
538 
539  bytestream2_init(&s->gb, buf, buf_size);
540 
541  /* check signature */
542  sig = bytestream2_get_be64(&s->gb);
543  if (sig != PNGSIG &&
544  sig != MNGSIG) {
545  av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
546  return AVERROR_INVALIDDATA;
547  }
548 
549  s->y = s->state = 0;
550 
551  /* init the zlib */
552  s->zstream.zalloc = ff_png_zalloc;
553  s->zstream.zfree = ff_png_zfree;
554  s->zstream.opaque = NULL;
555  ret = inflateInit(&s->zstream);
556  if (ret != Z_OK) {
557  av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
558  return AVERROR_EXTERNAL;
559  }
560  for (;;) {
561  if (bytestream2_get_bytes_left(&s->gb) <= 0) {
562  av_log(avctx, AV_LOG_ERROR, "%d bytes left\n", bytestream2_get_bytes_left(&s->gb));
563  if ( s->state & PNG_ALLIMAGE
564  && avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
565  goto exit_loop;
566  goto fail;
567  }
568 
569  length = bytestream2_get_be32(&s->gb);
570  if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
571  av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
572  goto fail;
573  }
574  tag = bytestream2_get_le32(&s->gb);
575  if (avctx->debug & FF_DEBUG_STARTCODE)
576  av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
577  (tag & 0xff),
578  ((tag >> 8) & 0xff),
579  ((tag >> 16) & 0xff),
580  ((tag >> 24) & 0xff), length);
581  switch (tag) {
582  case MKTAG('I', 'H', 'D', 'R'):
583  if (length != 13)
584  goto fail;
585  s->width = bytestream2_get_be32(&s->gb);
586  s->height = bytestream2_get_be32(&s->gb);
587  if (av_image_check_size(s->width, s->height, 0, avctx)) {
588  s->width = s->height = 0;
589  av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
590  goto fail;
591  }
592  s->bit_depth = bytestream2_get_byte(&s->gb);
593  s->color_type = bytestream2_get_byte(&s->gb);
594  s->compression_type = bytestream2_get_byte(&s->gb);
595  s->filter_type = bytestream2_get_byte(&s->gb);
596  s->interlace_type = bytestream2_get_byte(&s->gb);
597  bytestream2_skip(&s->gb, 4); /* crc */
598  s->state |= PNG_IHDR;
599  if (avctx->debug & FF_DEBUG_PICT_INFO)
600  av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
601  "compression_type=%d filter_type=%d interlace_type=%d\n",
602  s->width, s->height, s->bit_depth, s->color_type,
603  s->compression_type, s->filter_type, s->interlace_type);
604  break;
605  case MKTAG('p', 'H', 'Y', 's'):
606  if (s->state & PNG_IDAT) {
607  av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
608  goto fail;
609  }
610  avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
611  avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
612  if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
613  avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
614  bytestream2_skip(&s->gb, 1); /* unit specifier */
615  bytestream2_skip(&s->gb, 4); /* crc */
616  break;
617  case MKTAG('I', 'D', 'A', 'T'):
618  if (!(s->state & PNG_IHDR)) {
619  av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
620  goto fail;
621  }
622  if (!(s->state & PNG_IDAT)) {
623  /* init image info */
624  avctx->width = s->width;
625  avctx->height = s->height;
626 
627  s->channels = ff_png_get_nb_channels(s->color_type);
628  s->bits_per_pixel = s->bit_depth * s->channels;
629  s->bpp = (s->bits_per_pixel + 7) >> 3;
630  s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
631 
632  if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
633  s->color_type == PNG_COLOR_TYPE_RGB) {
634  avctx->pix_fmt = AV_PIX_FMT_RGB24;
635  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
636  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
637  avctx->pix_fmt = AV_PIX_FMT_RGBA;
638  } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
639  s->color_type == PNG_COLOR_TYPE_GRAY) {
640  avctx->pix_fmt = AV_PIX_FMT_GRAY8;
641  } else if (s->bit_depth == 16 &&
642  s->color_type == PNG_COLOR_TYPE_GRAY) {
643  avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
644  } else if (s->bit_depth == 16 &&
645  s->color_type == PNG_COLOR_TYPE_RGB) {
646  avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
647  } else if (s->bit_depth == 16 &&
648  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
649  avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
650  } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
651  s->color_type == PNG_COLOR_TYPE_PALETTE) {
652  avctx->pix_fmt = AV_PIX_FMT_PAL8;
653  } else if (s->bit_depth == 1) {
654  avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
655  } else if (s->bit_depth == 8 &&
656  s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
657  avctx->pix_fmt = AV_PIX_FMT_YA8;
658  } else if (s->bit_depth == 16 &&
659  s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
660  avctx->pix_fmt = AV_PIX_FMT_YA16BE;
661  } else {
662  av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
663  "and color type %d\n",
664  s->bit_depth, s->color_type);
665  goto fail;
666  }
667 
668  if (ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF) < 0)
669  goto fail;
670  ff_thread_finish_setup(avctx);
671 
672  p->pict_type = AV_PICTURE_TYPE_I;
673  p->key_frame = 1;
674  p->interlaced_frame = !!s->interlace_type;
675 
676  /* compute the compressed row size */
677  if (!s->interlace_type) {
678  s->crow_size = s->row_size + 1;
679  } else {
680  s->pass = 0;
681  s->pass_row_size = ff_png_pass_row_size(s->pass,
682  s->bits_per_pixel,
683  s->width);
684  s->crow_size = s->pass_row_size + 1;
685  }
686  av_dlog(avctx, "row_size=%d crow_size =%d\n",
687  s->row_size, s->crow_size);
688  s->image_buf = p->data[0];
689  s->image_linesize = p->linesize[0];
690  /* copy the palette if needed */
691  if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
692  memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
693  /* empty row is used if differencing to the first row */
694  av_fast_padded_mallocz(&s->last_row, &s->last_row_size, s->row_size);
695  if (!s->last_row)
696  goto fail;
697  if (s->interlace_type ||
698  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
699  av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
700  if (!s->tmp_row)
701  goto fail;
702  }
703  /* compressed row */
704  av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
705  if (!s->buffer)
706  goto fail;
707 
708  /* we want crow_buf+1 to be 16-byte aligned */
709  s->crow_buf = s->buffer + 15;
710  s->zstream.avail_out = s->crow_size;
711  s->zstream.next_out = s->crow_buf;
712  }
713  s->state |= PNG_IDAT;
714  if (png_decode_idat(s, length) < 0)
715  goto fail;
716  bytestream2_skip(&s->gb, 4); /* crc */
717  break;
718  case MKTAG('P', 'L', 'T', 'E'):
719  {
720  int n, i, r, g, b;
721 
722  if ((length % 3) != 0 || length > 256 * 3)
723  goto skip_tag;
724  /* read the palette */
725  n = length / 3;
726  for (i = 0; i < n; i++) {
727  r = bytestream2_get_byte(&s->gb);
728  g = bytestream2_get_byte(&s->gb);
729  b = bytestream2_get_byte(&s->gb);
730  s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
731  }
732  for (; i < 256; i++)
733  s->palette[i] = (0xFFU << 24);
734  s->state |= PNG_PLTE;
735  bytestream2_skip(&s->gb, 4); /* crc */
736  }
737  break;
738  case MKTAG('t', 'R', 'N', 'S'):
739  {
740  int v, i;
741 
742  /* read the transparency. XXX: Only palette mode supported */
743  if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
744  length > 256 ||
745  !(s->state & PNG_PLTE))
746  goto skip_tag;
747  for (i = 0; i < length; i++) {
748  v = bytestream2_get_byte(&s->gb);
749  s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
750  }
751  bytestream2_skip(&s->gb, 4); /* crc */
752  }
753  break;
754  case MKTAG('t', 'E', 'X', 't'):
755  if (decode_text_chunk(s, length, 0, &metadata) < 0)
756  av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
757  bytestream2_skip(&s->gb, length + 4);
758  break;
759  case MKTAG('z', 'T', 'X', 't'):
760  if (decode_text_chunk(s, length, 1, &metadata) < 0)
761  av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
762  bytestream2_skip(&s->gb, length + 4);
763  break;
764  case MKTAG('I', 'E', 'N', 'D'):
765  if (!(s->state & PNG_ALLIMAGE))
766  av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
767  if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
768  goto fail;
769  }
770  bytestream2_skip(&s->gb, 4); /* crc */
771  goto exit_loop;
772  default:
773  /* skip tag */
774 skip_tag:
775  bytestream2_skip(&s->gb, length + 4);
776  break;
777  }
778  }
779 exit_loop:
780 
781  if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
782  int i, j, k;
783  uint8_t *pd = p->data[0];
784  for (j = 0; j < s->height; j++) {
785  i = s->width / 8;
786  for (k = 7; k >= 1; k--)
787  if ((s->width&7) >= k)
788  pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
789  for (i--; i >= 0; i--) {
790  pd[8*i + 7]= pd[i] & 1;
791  pd[8*i + 6]= (pd[i]>>1) & 1;
792  pd[8*i + 5]= (pd[i]>>2) & 1;
793  pd[8*i + 4]= (pd[i]>>3) & 1;
794  pd[8*i + 3]= (pd[i]>>4) & 1;
795  pd[8*i + 2]= (pd[i]>>5) & 1;
796  pd[8*i + 1]= (pd[i]>>6) & 1;
797  pd[8*i + 0]= pd[i]>>7;
798  }
799  pd += s->image_linesize;
800  }
801  }
802  if (s->bits_per_pixel == 2){
803  int i, j;
804  uint8_t *pd = p->data[0];
805  for (j = 0; j < s->height; j++) {
806  i = s->width / 4;
807  if (s->color_type == PNG_COLOR_TYPE_PALETTE){
808  if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
809  if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
810  if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
811  for (i--; i >= 0; i--) {
812  pd[4*i + 3]= pd[i] & 3;
813  pd[4*i + 2]= (pd[i]>>2) & 3;
814  pd[4*i + 1]= (pd[i]>>4) & 3;
815  pd[4*i + 0]= pd[i]>>6;
816  }
817  } else {
818  if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
819  if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
820  if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
821  for (i--; i >= 0; i--) {
822  pd[4*i + 3]= ( pd[i] & 3)*0x55;
823  pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
824  pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
825  pd[4*i + 0]= ( pd[i]>>6 )*0x55;
826  }
827  }
828  pd += s->image_linesize;
829  }
830  }
831  if (s->bits_per_pixel == 4){
832  int i, j;
833  uint8_t *pd = p->data[0];
834  for (j = 0; j < s->height; j++) {
835  i = s->width/2;
836  if (s->color_type == PNG_COLOR_TYPE_PALETTE){
837  if (s->width&1) pd[2*i+0]= pd[i]>>4;
838  for (i--; i >= 0; i--) {
839  pd[2*i + 1] = pd[i] & 15;
840  pd[2*i + 0] = pd[i] >> 4;
841  }
842  } else {
843  if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
844  for (i--; i >= 0; i--) {
845  pd[2*i + 1] = (pd[i] & 15) * 0x11;
846  pd[2*i + 0] = (pd[i] >> 4) * 0x11;
847  }
848  }
849  pd += s->image_linesize;
850  }
851  }
852 
853  /* handle p-frames only if a predecessor frame is available */
854  if (s->last_picture.f->data[0]) {
855  if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
856  && s->last_picture.f->width == p->width
857  && s->last_picture.f->height== p->height
858  && s->last_picture.f->format== p->format
859  ) {
860  int i, j;
861  uint8_t *pd = p->data[0];
862  uint8_t *pd_last = s->last_picture.f->data[0];
863 
864  ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
865  for (j = 0; j < s->height; j++) {
866  for (i = 0; i < s->width * s->bpp; i++)
867  pd[i] += pd_last[i];
868  pd += s->image_linesize;
869  pd_last += s->image_linesize;
870  }
871  }
872  }
873  ff_thread_report_progress(&s->picture, INT_MAX, 0);
874 
875  av_frame_set_metadata(p, metadata);
876  metadata = NULL;
877 
878  if ((ret = av_frame_ref(data, s->picture.f)) < 0)
879  return ret;
880 
881  *got_frame = 1;
882 
883  ret = bytestream2_tell(&s->gb);
884 the_end:
885  inflateEnd(&s->zstream);
886  s->crow_buf = NULL;
887  return ret;
888 fail:
889  av_dict_free(&metadata);
890  ff_thread_report_progress(&s->picture, INT_MAX, 0);
891  ret = AVERROR_INVALIDDATA;
892  goto the_end;
893 }
894 
895 static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
896 {
897  PNGDecContext *psrc = src->priv_data;
898  PNGDecContext *pdst = dst->priv_data;
899 
900  if (dst == src)
901  return 0;
902 
903  ff_thread_release_buffer(dst, &pdst->picture);
904  if (psrc->picture.f->data[0])
905  return ff_thread_ref_frame(&pdst->picture, &psrc->picture);
906 
907  return 0;
908 }
909 
910 static av_cold int png_dec_init(AVCodecContext *avctx)
911 {
912  PNGDecContext *s = avctx->priv_data;
913 
914  s->avctx = avctx;
915  s->last_picture.f = av_frame_alloc();
916  s->picture.f = av_frame_alloc();
917  if (!s->last_picture.f || !s->picture.f)
918  return AVERROR(ENOMEM);
919 
920  if (!avctx->internal->is_copy) {
921  avctx->internal->allocate_progress = 1;
922  ff_pngdsp_init(&s->dsp);
923  }
924 
925  return 0;
926 }
927 
928 static av_cold int png_dec_end(AVCodecContext *avctx)
929 {
930  PNGDecContext *s = avctx->priv_data;
931 
932  ff_thread_release_buffer(avctx, &s->last_picture);
933  av_frame_free(&s->last_picture.f);
934  ff_thread_release_buffer(avctx, &s->picture);
935  av_frame_free(&s->picture.f);
936  av_freep(&s->buffer);
937  s->buffer_size = 0;
938  av_freep(&s->last_row);
939  s->last_row_size = 0;
940  av_freep(&s->tmp_row);
941  s->tmp_row_size = 0;
942 
943  return 0;
944 }
945 
946 AVCodec ff_png_decoder = {
947  .name = "png",
948  .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
949  .type = AVMEDIA_TYPE_VIDEO,
950  .id = AV_CODEC_ID_PNG,
951  .priv_data_size = sizeof(PNGDecContext),
952  .init = png_dec_init,
953  .close = png_dec_end,
954  .decode = decode_frame,
955  .init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
956  .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
957  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
958 };
Generated on Sun Sep 14 2014 18:56:02 for FFmpeg by   doxygen 1.8.2