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 Libav.
7  *
8  * Libav 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  * Libav 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 Libav; 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 "bytestream.h"
26 #define BITSTREAM_READER_LE
27 #include "get_bits.h"
28 // for av_memcpy_backptr
29 #include "libavutil/lzo.h"
30 
31 typedef struct XanContext {
34 
35  uint8_t *y_buffer;
36  uint8_t *scratch_buffer;
39 } XanContext;
40 
42 {
43  XanContext *s = avctx->priv_data;
44 
45  s->avctx = avctx;
46 
47  avctx->pix_fmt = PIX_FMT_YUV420P;
48 
49  s->buffer_size = avctx->width * avctx->height;
51  if (!s->y_buffer)
52  return AVERROR(ENOMEM);
53  s->scratch_buffer = av_malloc(s->buffer_size + 130);
54  if (!s->scratch_buffer) {
55  av_freep(&s->y_buffer);
56  return AVERROR(ENOMEM);
57  }
58 
59  return 0;
60 }
61 
63  uint8_t *dst, const int dst_size)
64 {
65  int tree_size, eof;
66  int bits, mask;
67  int tree_root, node;
68  const uint8_t *dst_end = dst + dst_size;
69  GetByteContext tree = s->gb;
70  int start_off = bytestream2_tell(&tree);
71 
72  tree_size = bytestream2_get_byte(&s->gb);
73  eof = bytestream2_get_byte(&s->gb);
74  tree_root = eof + tree_size;
75  bytestream2_skip(&s->gb, tree_size * 2);
76 
77  node = tree_root;
78  bits = bytestream2_get_byte(&s->gb);
79  mask = 0x80;
80  for (;;) {
81  int bit = !!(bits & mask);
82  mask >>= 1;
83  bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
84  node = bytestream2_get_byte(&tree);
85  if (node == eof)
86  break;
87  if (node < eof) {
88  *dst++ = node;
89  if (dst > dst_end)
90  break;
91  node = tree_root;
92  }
93  if (!mask) {
94  if (bytestream2_get_bytes_left(&s->gb) <= 0)
95  break;
96  bits = bytestream2_get_byteu(&s->gb);
97  mask = 0x80;
98  }
99  }
100  return dst != dst_end ? AVERROR_INVALIDDATA : 0;
101 }
102 
103 /* almost the same as in xan_wc3 decoder */
104 static int xan_unpack(XanContext *s,
105  uint8_t *dest, const int dest_len)
106 {
107  uint8_t opcode;
108  int size;
109  uint8_t *orig_dest = dest;
110  const uint8_t *dest_end = dest + dest_len;
111 
112  while (dest < dest_end) {
113  if (bytestream2_get_bytes_left(&s->gb) <= 0)
114  return AVERROR_INVALIDDATA;
115 
116  opcode = bytestream2_get_byteu(&s->gb);
117 
118  if (opcode < 0xe0) {
119  int size2, back;
120  if ((opcode & 0x80) == 0) {
121  size = opcode & 3;
122  back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
123  size2 = ((opcode & 0x1c) >> 2) + 3;
124  } else if ((opcode & 0x40) == 0) {
125  size = bytestream2_peek_byte(&s->gb) >> 6;
126  back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
127  size2 = (opcode & 0x3f) + 4;
128  } else {
129  size = opcode & 3;
130  back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
131  size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
132  if (size + size2 > dest_end - dest)
133  break;
134  }
135  if (dest + size + size2 > dest_end ||
136  dest - orig_dest + size < back)
137  return -1;
138  bytestream2_get_buffer(&s->gb, dest, size);
139  dest += size;
140  av_memcpy_backptr(dest, back, size2);
141  dest += size2;
142  } else {
143  int finish = opcode >= 0xfc;
144 
145  size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
146  if (dest_end - dest < size)
147  return -1;
148  bytestream2_get_buffer(&s->gb, dest, size);
149  dest += size;
150  if (finish)
151  break;
152  }
153  }
154  return dest - orig_dest;
155 }
156 
157 static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
158 {
159  XanContext *s = avctx->priv_data;
160  uint8_t *U, *V;
161  int val, uval, vval;
162  int i, j;
163  const uint8_t *src, *src_end;
164  const uint8_t *table;
165  int mode, offset, dec_size, table_size;
166 
167  if (!chroma_off)
168  return 0;
169  if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
170  av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
171  return -1;
172  }
173  bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
174  mode = bytestream2_get_le16(&s->gb);
175  table = s->gb.buffer;
176  table_size = bytestream2_get_le16(&s->gb);
177  offset = table_size * 2;
178  table_size += 1;
179 
180  if (offset >= bytestream2_get_bytes_left(&s->gb)) {
181  av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
182  return -1;
183  }
184 
185  bytestream2_skip(&s->gb, offset);
186  memset(s->scratch_buffer, 0, s->buffer_size);
187  dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
188  if (dec_size < 0) {
189  av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
190  return -1;
191  }
192 
193  U = s->pic.data[1];
194  V = s->pic.data[2];
195  src = s->scratch_buffer;
196  src_end = src + dec_size;
197  if (mode) {
198  for (j = 0; j < avctx->height >> 1; j++) {
199  for (i = 0; i < avctx->width >> 1; i++) {
200  val = *src++;
201  if (val && val < table_size) {
202  val = AV_RL16(table + (val << 1));
203  uval = (val >> 3) & 0xF8;
204  vval = (val >> 8) & 0xF8;
205  U[i] = uval | (uval >> 5);
206  V[i] = vval | (vval >> 5);
207  }
208  if (src == src_end)
209  return 0;
210  }
211  U += s->pic.linesize[1];
212  V += s->pic.linesize[2];
213  }
214  } else {
215  uint8_t *U2 = U + s->pic.linesize[1];
216  uint8_t *V2 = V + s->pic.linesize[2];
217 
218  for (j = 0; j < avctx->height >> 2; j++) {
219  for (i = 0; i < avctx->width >> 1; i += 2) {
220  val = *src++;
221  if (val && val < table_size) {
222  val = AV_RL16(table + (val << 1));
223  uval = (val >> 3) & 0xF8;
224  vval = (val >> 8) & 0xF8;
225  U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
226  V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
227  }
228  }
229  U += s->pic.linesize[1] * 2;
230  V += s->pic.linesize[2] * 2;
231  U2 += s->pic.linesize[1] * 2;
232  V2 += s->pic.linesize[2] * 2;
233  }
234  }
235 
236  return 0;
237 }
238 
240 {
241  XanContext *s = avctx->priv_data;
242  uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
243  unsigned chroma_off, corr_off;
244  int cur, last;
245  int i, j;
246  int ret;
247 
248  chroma_off = bytestream2_get_le32(&s->gb);
249  corr_off = bytestream2_get_le32(&s->gb);
250 
251  if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
252  return ret;
253 
254  if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) {
255  av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
256  corr_off = 0;
257  }
258  bytestream2_seek(&s->gb, 12, SEEK_SET);
259  ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
260  if (ret) {
261  av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
262  return ret;
263  }
264 
265  ybuf = s->y_buffer;
266  last = *src++;
267  ybuf[0] = last << 1;
268  for (j = 1; j < avctx->width - 1; j += 2) {
269  cur = (last + *src++) & 0x1F;
270  ybuf[j] = last + cur;
271  ybuf[j+1] = cur << 1;
272  last = cur;
273  }
274  ybuf[j] = last << 1;
275  prev_buf = ybuf;
276  ybuf += avctx->width;
277 
278  for (i = 1; i < avctx->height; i++) {
279  last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
280  ybuf[0] = last << 1;
281  for (j = 1; j < avctx->width - 1; j += 2) {
282  cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
283  ybuf[j] = last + cur;
284  ybuf[j+1] = cur << 1;
285  last = cur;
286  }
287  ybuf[j] = last << 1;
288  prev_buf = ybuf;
289  ybuf += avctx->width;
290  }
291 
292  if (corr_off) {
293  int corr_end, dec_size;
294 
295  corr_end = (s->gb.buffer_end - s->gb.buffer_start);
296  if (chroma_off > corr_off)
297  corr_end = chroma_off;
298  bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
299  dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
300  if (dec_size < 0)
301  dec_size = 0;
302  for (i = 0; i < dec_size; i++)
303  s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
304  }
305 
306  src = s->y_buffer;
307  ybuf = s->pic.data[0];
308  for (j = 0; j < avctx->height; j++) {
309  for (i = 0; i < avctx->width; i++)
310  ybuf[i] = (src[i] << 2) | (src[i] >> 3);
311  src += avctx->width;
312  ybuf += s->pic.linesize[0];
313  }
314 
315  return 0;
316 }
317 
319 {
320  XanContext *s = avctx->priv_data;
321  uint8_t *ybuf, *src = s->scratch_buffer;
322  int cur, last;
323  int i, j;
324  int ret;
325 
326  if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
327  return ret;
328 
329  bytestream2_seek(&s->gb, 16, SEEK_SET);
330  ret = xan_unpack_luma(s, src,
331  s->buffer_size >> 1);
332  if (ret) {
333  av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
334  return ret;
335  }
336 
337  ybuf = s->y_buffer;
338  for (i = 0; i < avctx->height; i++) {
339  last = (ybuf[0] + (*src++ << 1)) & 0x3F;
340  ybuf[0] = last;
341  for (j = 1; j < avctx->width - 1; j += 2) {
342  cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
343  ybuf[j] = (last + cur) >> 1;
344  ybuf[j+1] = cur;
345  last = cur;
346  }
347  ybuf[j] = last;
348  ybuf += avctx->width;
349  }
350 
351  src = s->y_buffer;
352  ybuf = s->pic.data[0];
353  for (j = 0; j < avctx->height; j++) {
354  for (i = 0; i < avctx->width; i++)
355  ybuf[i] = (src[i] << 2) | (src[i] >> 3);
356  src += avctx->width;
357  ybuf += s->pic.linesize[0];
358  }
359 
360  return 0;
361 }
362 
364  void *data, int *data_size,
365  AVPacket *avpkt)
366 {
367  XanContext *s = avctx->priv_data;
368  int ftype;
369  int ret;
370 
371  s->pic.reference = 1;
375  if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
376  av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
377  return ret;
378  }
379 
380  bytestream2_init(&s->gb, avpkt->data, avpkt->size);
381  ftype = bytestream2_get_le32(&s->gb);
382  switch (ftype) {
383  case 0:
384  ret = xan_decode_frame_type0(avctx);
385  break;
386  case 1:
387  ret = xan_decode_frame_type1(avctx);
388  break;
389  default:
390  av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
391  return -1;
392  }
393  if (ret)
394  return ret;
395 
396  *data_size = sizeof(AVFrame);
397  *(AVFrame*)data = s->pic;
398 
399  return avpkt->size;
400 }
401 
403 {
404  XanContext *s = avctx->priv_data;
405 
406  if (s->pic.data[0])
407  avctx->release_buffer(avctx, &s->pic);
408 
409  av_freep(&s->y_buffer);
411 
412  return 0;
413 }
414 
416  .name = "xan_wc4",
417  .type = AVMEDIA_TYPE_VIDEO,
418  .id = CODEC_ID_XAN_WC4,
419  .priv_data_size = sizeof(XanContext),
423  .capabilities = CODEC_CAP_DR1,
424  .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
425 };
426