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xxan.c
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1 /*
2  * Wing Commander/Xan Video Decoder
3  * Copyright (C) 2011 Konstantin Shishkov
4  * based on work by Mike Melanson
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 "avcodec.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26 #include "bytestream.h"
27 #define BITSTREAM_READER_LE
28 #include "get_bits.h"
29 #include "internal.h"
30 
31 typedef struct XanContext {
34 
39 } XanContext;
40 
41 static av_cold int xan_decode_end(AVCodecContext *avctx);
42 
44 {
45  XanContext *s = avctx->priv_data;
46 
47  s->avctx = avctx;
48 
49  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
50 
51  if (avctx->height < 8) {
52  av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
53  return AVERROR(EINVAL);
54  }
55 
56  s->buffer_size = avctx->width * avctx->height;
58  if (!s->y_buffer)
59  return AVERROR(ENOMEM);
60  s->scratch_buffer = av_malloc(s->buffer_size + 130);
61  if (!s->scratch_buffer) {
62  xan_decode_end(avctx);
63  return AVERROR(ENOMEM);
64  }
65 
66  s->pic = av_frame_alloc();
67  if (!s->pic) {
68  xan_decode_end(avctx);
69  return AVERROR(ENOMEM);
70  }
71 
72  return 0;
73 }
74 
76  uint8_t *dst, const int dst_size)
77 {
78  int tree_size, eof;
79  int bits, mask;
80  int tree_root, node;
81  const uint8_t *dst_end = dst + dst_size;
82  GetByteContext tree = s->gb;
83  int start_off = bytestream2_tell(&tree);
84 
85  tree_size = bytestream2_get_byte(&s->gb);
86  eof = bytestream2_get_byte(&s->gb);
87  tree_root = eof + tree_size;
88  bytestream2_skip(&s->gb, tree_size * 2);
89 
90  node = tree_root;
91  bits = bytestream2_get_byte(&s->gb);
92  mask = 0x80;
93  for (;;) {
94  int bit = !!(bits & mask);
95  mask >>= 1;
96  bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
97  node = bytestream2_get_byte(&tree);
98  if (node == eof)
99  break;
100  if (node < eof) {
101  *dst++ = node;
102  if (dst > dst_end)
103  break;
104  node = tree_root;
105  }
106  if (!mask) {
107  if (bytestream2_get_bytes_left(&s->gb) <= 0)
108  break;
109  bits = bytestream2_get_byteu(&s->gb);
110  mask = 0x80;
111  }
112  }
113  return dst != dst_end ? AVERROR_INVALIDDATA : 0;
114 }
115 
116 /* almost the same as in xan_wc3 decoder */
117 static int xan_unpack(XanContext *s,
118  uint8_t *dest, const int dest_len)
119 {
120  uint8_t opcode;
121  int size;
122  uint8_t *orig_dest = dest;
123  const uint8_t *dest_end = dest + dest_len;
124 
125  while (dest < dest_end) {
126  if (bytestream2_get_bytes_left(&s->gb) <= 0)
127  return AVERROR_INVALIDDATA;
128 
129  opcode = bytestream2_get_byteu(&s->gb);
130 
131  if (opcode < 0xe0) {
132  int size2, back;
133  if ((opcode & 0x80) == 0) {
134  size = opcode & 3;
135  back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
136  size2 = ((opcode & 0x1c) >> 2) + 3;
137  } else if ((opcode & 0x40) == 0) {
138  size = bytestream2_peek_byte(&s->gb) >> 6;
139  back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
140  size2 = (opcode & 0x3f) + 4;
141  } else {
142  size = opcode & 3;
143  back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
144  size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
145  if (size + size2 > dest_end - dest)
146  break;
147  }
148  if (dest + size + size2 > dest_end ||
149  dest - orig_dest + size < back)
150  return AVERROR_INVALIDDATA;
151  bytestream2_get_buffer(&s->gb, dest, size);
152  dest += size;
153  av_memcpy_backptr(dest, back, size2);
154  dest += size2;
155  } else {
156  int finish = opcode >= 0xfc;
157 
158  size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
159  if (dest_end - dest < size)
160  return AVERROR_INVALIDDATA;
161  bytestream2_get_buffer(&s->gb, dest, size);
162  dest += size;
163  if (finish)
164  break;
165  }
166  }
167  return dest - orig_dest;
168 }
169 
170 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
171 {
172  XanContext *s = avctx->priv_data;
173  uint8_t *U, *V;
174  int val, uval, vval;
175  int i, j;
176  const uint8_t *src, *src_end;
177  const uint8_t *table;
178  int mode, offset, dec_size, table_size;
179 
180  if (!chroma_off)
181  return 0;
182  if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
183  av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
184  return AVERROR_INVALIDDATA;
185  }
186  bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
187  mode = bytestream2_get_le16(&s->gb);
188  table = s->gb.buffer;
189  table_size = bytestream2_get_le16(&s->gb);
190  offset = table_size * 2;
191  table_size += 1;
192 
193  if (offset >= bytestream2_get_bytes_left(&s->gb)) {
194  av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
195  return AVERROR_INVALIDDATA;
196  }
197 
198  bytestream2_skip(&s->gb, offset);
199  memset(s->scratch_buffer, 0, s->buffer_size);
200  dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
201  if (dec_size < 0) {
202  av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
203  return dec_size;
204  }
205 
206  U = s->pic->data[1];
207  V = s->pic->data[2];
208  src = s->scratch_buffer;
209  src_end = src + dec_size;
210  if (mode) {
211  for (j = 0; j < avctx->height >> 1; j++) {
212  for (i = 0; i < avctx->width >> 1; i++) {
213  if (src_end - src < 1)
214  return 0;
215  val = *src++;
216  if (val) {
217  if (val >= table_size)
218  return AVERROR_INVALIDDATA;
219  val = AV_RL16(table + (val << 1));
220  uval = (val >> 3) & 0xF8;
221  vval = (val >> 8) & 0xF8;
222  U[i] = uval | (uval >> 5);
223  V[i] = vval | (vval >> 5);
224  }
225  }
226  U += s->pic->linesize[1];
227  V += s->pic->linesize[2];
228  }
229  if (avctx->height & 1) {
230  memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
231  memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
232  }
233  } else {
234  uint8_t *U2 = U + s->pic->linesize[1];
235  uint8_t *V2 = V + s->pic->linesize[2];
236 
237  for (j = 0; j < avctx->height >> 2; j++) {
238  for (i = 0; i < avctx->width >> 1; i += 2) {
239  if (src_end - src < 1)
240  return 0;
241  val = *src++;
242  if (val) {
243  if (val >= table_size)
244  return AVERROR_INVALIDDATA;
245  val = AV_RL16(table + (val << 1));
246  uval = (val >> 3) & 0xF8;
247  vval = (val >> 8) & 0xF8;
248  U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
249  V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
250  }
251  }
252  U += s->pic->linesize[1] * 2;
253  V += s->pic->linesize[2] * 2;
254  U2 += s->pic->linesize[1] * 2;
255  V2 += s->pic->linesize[2] * 2;
256  }
257  if (avctx->height & 3) {
258  int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
259 
260  memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
261  memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
262  }
263  }
264 
265  return 0;
266 }
267 
269 {
270  XanContext *s = avctx->priv_data;
271  uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
272  unsigned chroma_off, corr_off;
273  int cur, last;
274  int i, j;
275  int ret;
276 
277  chroma_off = bytestream2_get_le32(&s->gb);
278  corr_off = bytestream2_get_le32(&s->gb);
279 
280  if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
281  return ret;
282 
283  if (corr_off >= bytestream2_size(&s->gb)) {
284  av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
285  corr_off = 0;
286  }
287  bytestream2_seek(&s->gb, 12, SEEK_SET);
288  ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
289  if (ret) {
290  av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
291  return ret;
292  }
293 
294  ybuf = s->y_buffer;
295  last = *src++;
296  ybuf[0] = last << 1;
297  for (j = 1; j < avctx->width - 1; j += 2) {
298  cur = (last + *src++) & 0x1F;
299  ybuf[j] = last + cur;
300  ybuf[j+1] = cur << 1;
301  last = cur;
302  }
303  if(j < avctx->width)
304  ybuf[j] = last << 1;
305  prev_buf = ybuf;
306  ybuf += avctx->width;
307 
308  for (i = 1; i < avctx->height; i++) {
309  last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
310  ybuf[0] = last << 1;
311  for (j = 1; j < avctx->width - 1; j += 2) {
312  cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
313  ybuf[j] = last + cur;
314  ybuf[j+1] = cur << 1;
315  last = cur;
316  }
317  if(j < avctx->width)
318  ybuf[j] = last << 1;
319  prev_buf = ybuf;
320  ybuf += avctx->width;
321  }
322 
323  if (corr_off) {
324  int dec_size;
325 
326  bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
327  dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
328  if (dec_size < 0)
329  dec_size = 0;
330  else
331  dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
332 
333  for (i = 0; i < dec_size; i++)
334  s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
335  }
336 
337  src = s->y_buffer;
338  ybuf = s->pic->data[0];
339  for (j = 0; j < avctx->height; j++) {
340  for (i = 0; i < avctx->width; i++)
341  ybuf[i] = (src[i] << 2) | (src[i] >> 3);
342  src += avctx->width;
343  ybuf += s->pic->linesize[0];
344  }
345 
346  return 0;
347 }
348 
350 {
351  XanContext *s = avctx->priv_data;
352  uint8_t *ybuf, *src = s->scratch_buffer;
353  int cur, last;
354  int i, j;
355  int ret;
356 
357  if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
358  return ret;
359 
360  bytestream2_seek(&s->gb, 16, SEEK_SET);
361  ret = xan_unpack_luma(s, src,
362  s->buffer_size >> 1);
363  if (ret) {
364  av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
365  return ret;
366  }
367 
368  ybuf = s->y_buffer;
369  for (i = 0; i < avctx->height; i++) {
370  last = (ybuf[0] + (*src++ << 1)) & 0x3F;
371  ybuf[0] = last;
372  for (j = 1; j < avctx->width - 1; j += 2) {
373  cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
374  ybuf[j] = (last + cur) >> 1;
375  ybuf[j+1] = cur;
376  last = cur;
377  }
378  if(j < avctx->width)
379  ybuf[j] = last;
380  ybuf += avctx->width;
381  }
382 
383  src = s->y_buffer;
384  ybuf = s->pic->data[0];
385  for (j = 0; j < avctx->height; j++) {
386  for (i = 0; i < avctx->width; i++)
387  ybuf[i] = (src[i] << 2) | (src[i] >> 3);
388  src += avctx->width;
389  ybuf += s->pic->linesize[0];
390  }
391 
392  return 0;
393 }
394 
396  void *data, int *got_frame,
397  AVPacket *avpkt)
398 {
399  XanContext *s = avctx->priv_data;
400  int ftype;
401  int ret;
402 
403  if ((ret = ff_reget_buffer(avctx, s->pic)) < 0)
404  return ret;
405 
406  bytestream2_init(&s->gb, avpkt->data, avpkt->size);
407  ftype = bytestream2_get_le32(&s->gb);
408  switch (ftype) {
409  case 0:
410  ret = xan_decode_frame_type0(avctx);
411  break;
412  case 1:
413  ret = xan_decode_frame_type1(avctx);
414  break;
415  default:
416  av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
417  return AVERROR_INVALIDDATA;
418  }
419  if (ret)
420  return ret;
421 
422  if ((ret = av_frame_ref(data, s->pic)) < 0)
423  return ret;
424 
425  *got_frame = 1;
426 
427  return avpkt->size;
428 }
429 
431 {
432  XanContext *s = avctx->priv_data;
433 
434  av_frame_free(&s->pic);
435 
436  av_freep(&s->y_buffer);
438 
439  return 0;
440 }
441 
443  .name = "xan_wc4",
444  .type = AVMEDIA_TYPE_VIDEO,
445  .id = AV_CODEC_ID_XAN_WC4,
446  .priv_data_size = sizeof(XanContext),
450  .capabilities = CODEC_CAP_DR1,
451  .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
452 };