FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
dfa.c
Go to the documentation of this file.
1 /*
2  * Chronomaster DFA Video Decoder
3  * Copyright (c) 2011 Konstantin Shishkov
4  * based on work by Vladimir "VAG" Gneushev
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "libavutil/avassert.h"
24 #include "avcodec.h"
25 #include "bytestream.h"
26 #include "internal.h"
27 
28 #include "libavutil/imgutils.h"
29 #include "libavutil/mem.h"
30 
31 typedef struct DfaContext {
32  AVFrame pic;
33 
34  uint32_t pal[256];
35  uint8_t *frame_buf;
36 } DfaContext;
37 
38 static av_cold int dfa_decode_init(AVCodecContext *avctx)
39 {
40  DfaContext *s = avctx->priv_data;
41 
42  avctx->pix_fmt = AV_PIX_FMT_PAL8;
43 
44  if (!avctx->width || !avctx->height)
45  return AVERROR_INVALIDDATA;
46 
47  av_assert0(av_image_check_size(avctx->width, avctx->height, 0, avctx) >= 0);
48 
49  s->frame_buf = av_mallocz(avctx->width * avctx->height);
50  if (!s->frame_buf)
51  return AVERROR(ENOMEM);
52 
53  return 0;
54 }
55 
56 static int decode_copy(GetByteContext *gb, uint8_t *frame, int width, int height)
57 {
58  const int size = width * height;
59 
60  if (bytestream2_get_buffer(gb, frame, size) != size)
61  return AVERROR_INVALIDDATA;
62  return 0;
63 }
64 
65 static int decode_tsw1(GetByteContext *gb, uint8_t *frame, int width, int height)
66 {
67  const uint8_t *frame_start = frame;
68  const uint8_t *frame_end = frame + width * height;
69  int mask = 0x10000, bitbuf = 0;
70  int v, count, segments;
71  unsigned offset;
72 
73  segments = bytestream2_get_le32(gb);
74  offset = bytestream2_get_le32(gb);
75  if (segments == 0 && offset == frame_end - frame)
76  return 0; // skip frame
77  if (frame_end - frame <= offset)
78  return AVERROR_INVALIDDATA;
79  frame += offset;
80  while (segments--) {
81  if (bytestream2_get_bytes_left(gb) < 2)
82  return AVERROR_INVALIDDATA;
83  if (mask == 0x10000) {
84  bitbuf = bytestream2_get_le16u(gb);
85  mask = 1;
86  }
87  if (frame_end - frame < 2)
88  return AVERROR_INVALIDDATA;
89  if (bitbuf & mask) {
90  v = bytestream2_get_le16(gb);
91  offset = (v & 0x1FFF) << 1;
92  count = ((v >> 13) + 2) << 1;
93  if (frame - frame_start < offset || frame_end - frame < count)
94  return AVERROR_INVALIDDATA;
95  av_memcpy_backptr(frame, offset, count);
96  frame += count;
97  } else {
98  *frame++ = bytestream2_get_byte(gb);
99  *frame++ = bytestream2_get_byte(gb);
100  }
101  mask <<= 1;
102  }
103 
104  return 0;
105 }
106 
107 static int decode_dsw1(GetByteContext *gb, uint8_t *frame, int width, int height)
108 {
109  const uint8_t *frame_start = frame;
110  const uint8_t *frame_end = frame + width * height;
111  int mask = 0x10000, bitbuf = 0;
112  int v, offset, count, segments;
113 
114  segments = bytestream2_get_le16(gb);
115  while (segments--) {
116  if (bytestream2_get_bytes_left(gb) < 2)
117  return AVERROR_INVALIDDATA;
118  if (mask == 0x10000) {
119  bitbuf = bytestream2_get_le16u(gb);
120  mask = 1;
121  }
122  if (frame_end - frame < 2)
123  return AVERROR_INVALIDDATA;
124  if (bitbuf & mask) {
125  v = bytestream2_get_le16(gb);
126  offset = (v & 0x1FFF) << 1;
127  count = ((v >> 13) + 2) << 1;
128  if (frame - frame_start < offset || frame_end - frame < count)
129  return AVERROR_INVALIDDATA;
130  av_memcpy_backptr(frame, offset, count);
131  frame += count;
132  } else if (bitbuf & (mask << 1)) {
133  frame += bytestream2_get_le16(gb);
134  } else {
135  *frame++ = bytestream2_get_byte(gb);
136  *frame++ = bytestream2_get_byte(gb);
137  }
138  mask <<= 2;
139  }
140 
141  return 0;
142 }
143 
144 static int decode_dds1(GetByteContext *gb, uint8_t *frame, int width, int height)
145 {
146  const uint8_t *frame_start = frame;
147  const uint8_t *frame_end = frame + width * height;
148  int mask = 0x10000, bitbuf = 0;
149  int i, v, offset, count, segments;
150 
151  segments = bytestream2_get_le16(gb);
152  while (segments--) {
153  if (bytestream2_get_bytes_left(gb) < 2)
154  return AVERROR_INVALIDDATA;
155  if (mask == 0x10000) {
156  bitbuf = bytestream2_get_le16u(gb);
157  mask = 1;
158  }
159 
160  if (bitbuf & mask) {
161  v = bytestream2_get_le16(gb);
162  offset = (v & 0x1FFF) << 2;
163  count = ((v >> 13) + 2) << 1;
164  if (frame - frame_start < offset || frame_end - frame < count*2 + width)
165  return AVERROR_INVALIDDATA;
166  for (i = 0; i < count; i++) {
167  frame[0] = frame[1] =
168  frame[width] = frame[width + 1] = frame[-offset];
169 
170  frame += 2;
171  }
172  } else if (bitbuf & (mask << 1)) {
173  v = bytestream2_get_le16(gb)*2;
174  if (frame - frame_end < v)
175  return AVERROR_INVALIDDATA;
176  frame += v;
177  } else {
178  if (frame_end - frame < width + 3)
179  return AVERROR_INVALIDDATA;
180  frame[0] = frame[1] =
181  frame[width] = frame[width + 1] = bytestream2_get_byte(gb);
182  frame += 2;
183  frame[0] = frame[1] =
184  frame[width] = frame[width + 1] = bytestream2_get_byte(gb);
185  frame += 2;
186  }
187  mask <<= 2;
188  }
189 
190  return 0;
191 }
192 
193 static int decode_bdlt(GetByteContext *gb, uint8_t *frame, int width, int height)
194 {
195  uint8_t *line_ptr;
196  int count, lines, segments;
197 
198  count = bytestream2_get_le16(gb);
199  if (count >= height)
200  return AVERROR_INVALIDDATA;
201  frame += width * count;
202  lines = bytestream2_get_le16(gb);
203  if (count + lines > height)
204  return AVERROR_INVALIDDATA;
205 
206  while (lines--) {
207  if (bytestream2_get_bytes_left(gb) < 1)
208  return AVERROR_INVALIDDATA;
209  line_ptr = frame;
210  frame += width;
211  segments = bytestream2_get_byteu(gb);
212  while (segments--) {
213  if (frame - line_ptr <= bytestream2_peek_byte(gb))
214  return AVERROR_INVALIDDATA;
215  line_ptr += bytestream2_get_byte(gb);
216  count = (int8_t)bytestream2_get_byte(gb);
217  if (count >= 0) {
218  if (frame - line_ptr < count)
219  return AVERROR_INVALIDDATA;
220  if (bytestream2_get_buffer(gb, line_ptr, count) != count)
221  return AVERROR_INVALIDDATA;
222  } else {
223  count = -count;
224  if (frame - line_ptr < count)
225  return AVERROR_INVALIDDATA;
226  memset(line_ptr, bytestream2_get_byte(gb), count);
227  }
228  line_ptr += count;
229  }
230  }
231 
232  return 0;
233 }
234 
235 static int decode_wdlt(GetByteContext *gb, uint8_t *frame, int width, int height)
236 {
237  const uint8_t *frame_end = frame + width * height;
238  uint8_t *line_ptr;
239  int count, i, v, lines, segments;
240  int y = 0;
241 
242  lines = bytestream2_get_le16(gb);
243  if (lines > height)
244  return AVERROR_INVALIDDATA;
245 
246  while (lines--) {
247  if (bytestream2_get_bytes_left(gb) < 2)
248  return AVERROR_INVALIDDATA;
249  segments = bytestream2_get_le16u(gb);
250  while ((segments & 0xC000) == 0xC000) {
251  unsigned skip_lines = -(int16_t)segments;
252  unsigned delta = -((int16_t)segments * width);
253  if (frame_end - frame <= delta || y + lines + skip_lines > height)
254  return AVERROR_INVALIDDATA;
255  frame += delta;
256  y += skip_lines;
257  segments = bytestream2_get_le16(gb);
258  }
259  if (frame_end <= frame)
260  return -1;
261  if (segments & 0x8000) {
262  frame[width - 1] = segments & 0xFF;
263  segments = bytestream2_get_le16(gb);
264  }
265  line_ptr = frame;
266  frame += width;
267  y++;
268  while (segments--) {
269  if (frame - line_ptr <= bytestream2_peek_byte(gb))
270  return AVERROR_INVALIDDATA;
271  line_ptr += bytestream2_get_byte(gb);
272  count = (int8_t)bytestream2_get_byte(gb);
273  if (count >= 0) {
274  if (frame - line_ptr < count * 2)
275  return AVERROR_INVALIDDATA;
276  if (bytestream2_get_buffer(gb, line_ptr, count * 2) != count * 2)
277  return AVERROR_INVALIDDATA;
278  line_ptr += count * 2;
279  } else {
280  count = -count;
281  if (frame - line_ptr < count * 2)
282  return AVERROR_INVALIDDATA;
283  v = bytestream2_get_le16(gb);
284  for (i = 0; i < count; i++)
285  bytestream_put_le16(&line_ptr, v);
286  }
287  }
288  }
289 
290  return 0;
291 }
292 
293 static int decode_unk6(GetByteContext *gb, uint8_t *frame, int width, int height)
294 {
295  return AVERROR_PATCHWELCOME;
296 }
297 
298 static int decode_blck(GetByteContext *gb, uint8_t *frame, int width, int height)
299 {
300  memset(frame, 0, width * height);
301  return 0;
302 }
303 
304 
305 typedef int (*chunk_decoder)(GetByteContext *gb, uint8_t *frame, int width, int height);
306 
307 static const chunk_decoder decoder[8] = {
308  decode_copy, decode_tsw1, decode_bdlt, decode_wdlt,
309  decode_unk6, decode_dsw1, decode_blck, decode_dds1,
310 };
311 
312 static const char* chunk_name[8] = {
313  "COPY", "TSW1", "BDLT", "WDLT", "????", "DSW1", "BLCK", "DDS1"
314 };
315 
316 static int dfa_decode_frame(AVCodecContext *avctx,
317  void *data, int *got_frame,
318  AVPacket *avpkt)
319 {
320  DfaContext *s = avctx->priv_data;
321  GetByteContext gb;
322  const uint8_t *buf = avpkt->data;
323  uint32_t chunk_type, chunk_size;
324  uint8_t *dst;
325  int ret;
326  int i, pal_elems;
327 
328  if (s->pic.data[0])
329  avctx->release_buffer(avctx, &s->pic);
330 
331  if ((ret = ff_get_buffer(avctx, &s->pic))) {
332  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
333  return ret;
334  }
335 
336  bytestream2_init(&gb, avpkt->data, avpkt->size);
337  while (bytestream2_get_bytes_left(&gb) > 0) {
338  bytestream2_skip(&gb, 4);
339  chunk_size = bytestream2_get_le32(&gb);
340  chunk_type = bytestream2_get_le32(&gb);
341  if (!chunk_type)
342  break;
343  if (chunk_type == 1) {
344  pal_elems = FFMIN(chunk_size / 3, 256);
345  for (i = 0; i < pal_elems; i++) {
346  s->pal[i] = bytestream2_get_be24(&gb) << 2;
347  s->pal[i] |= 0xFFU << 24 | (s->pal[i] >> 6) & 0x30303;
348  }
349  s->pic.palette_has_changed = 1;
350  } else if (chunk_type <= 9) {
351  if (decoder[chunk_type - 2](&gb, s->frame_buf, avctx->width, avctx->height)) {
352  av_log(avctx, AV_LOG_ERROR, "Error decoding %s chunk\n",
353  chunk_name[chunk_type - 2]);
354  return AVERROR_INVALIDDATA;
355  }
356  } else {
357  av_log(avctx, AV_LOG_WARNING, "Ignoring unknown chunk type %d\n",
358  chunk_type);
359  }
360  buf += chunk_size;
361  }
362 
363  buf = s->frame_buf;
364  dst = s->pic.data[0];
365  for (i = 0; i < avctx->height; i++) {
366  memcpy(dst, buf, avctx->width);
367  dst += s->pic.linesize[0];
368  buf += avctx->width;
369  }
370  memcpy(s->pic.data[1], s->pal, sizeof(s->pal));
371 
372  *got_frame = 1;
373  *(AVFrame*)data = s->pic;
374 
375  return avpkt->size;
376 }
377 
378 static av_cold int dfa_decode_end(AVCodecContext *avctx)
379 {
380  DfaContext *s = avctx->priv_data;
381 
382  if (s->pic.data[0])
383  avctx->release_buffer(avctx, &s->pic);
384 
385  av_freep(&s->frame_buf);
386 
387  return 0;
388 }
389 
390 AVCodec ff_dfa_decoder = {
391  .name = "dfa",
392  .type = AVMEDIA_TYPE_VIDEO,
393  .id = AV_CODEC_ID_DFA,
394  .priv_data_size = sizeof(DfaContext),
395  .init = dfa_decode_init,
396  .close = dfa_decode_end,
397  .decode = dfa_decode_frame,
398  .capabilities = CODEC_CAP_DR1,
399  .long_name = NULL_IF_CONFIG_SMALL("Chronomaster DFA"),
400 };
Generated on Sat May 25 2013 04:01:02 for FFmpeg by   doxygen 1.8.2