dxa.c
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1 /*
2  * Feeble Files/ScummVM DXA decoder
3  * Copyright (c) 2007 Konstantin Shishkov
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #include <stdio.h>
28 #include <stdlib.h>
29 
30 #include "libavutil/common.h"
31 #include "libavutil/intreadwrite.h"
32 #include "avcodec.h"
33 #include "internal.h"
34 
35 #include <zlib.h>
36 
37 /*
38  * Decoder context
39  */
40 typedef struct DxaDecContext {
42 
43  int dsize;
45  uint32_t pal[256];
47 
48 static const int shift1[6] = { 0, 8, 8, 8, 4, 4 };
49 static const int shift2[6] = { 0, 0, 8, 4, 0, 4 };
50 
51 static int decode_13(AVCodecContext *avctx, DxaDecContext *c, uint8_t* dst, uint8_t *src, uint8_t *ref)
52 {
53  uint8_t *code, *data, *mv, *msk, *tmp, *tmp2;
54  int i, j, k;
55  int type, x, y, d, d2;
56  int stride = c->pic.linesize[0];
57  uint32_t mask;
58 
59  code = src + 12;
60  data = code + ((avctx->width * avctx->height) >> 4);
61  mv = data + AV_RB32(src + 0);
62  msk = mv + AV_RB32(src + 4);
63 
64  for(j = 0; j < avctx->height; j += 4){
65  for(i = 0; i < avctx->width; i += 4){
66  tmp = dst + i;
67  tmp2 = ref + i;
68  type = *code++;
69  switch(type){
70  case 4: // motion compensation
71  x = (*mv) >> 4; if(x & 8) x = 8 - x;
72  y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
73  tmp2 += x + y*stride;
74  case 0: // skip
75  case 5: // skip in method 12
76  for(y = 0; y < 4; y++){
77  memcpy(tmp, tmp2, 4);
78  tmp += stride;
79  tmp2 += stride;
80  }
81  break;
82  case 1: // masked change
83  case 10: // masked change with only half of pixels changed
84  case 11: // cases 10-15 are for method 12 only
85  case 12:
86  case 13:
87  case 14:
88  case 15:
89  if(type == 1){
90  mask = AV_RB16(msk);
91  msk += 2;
92  }else{
93  type -= 10;
94  mask = ((msk[0] & 0xF0) << shift1[type]) | ((msk[0] & 0xF) << shift2[type]);
95  msk++;
96  }
97  for(y = 0; y < 4; y++){
98  for(x = 0; x < 4; x++){
99  tmp[x] = (mask & 0x8000) ? *data++ : tmp2[x];
100  mask <<= 1;
101  }
102  tmp += stride;
103  tmp2 += stride;
104  }
105  break;
106  case 2: // fill block
107  for(y = 0; y < 4; y++){
108  memset(tmp, data[0], 4);
109  tmp += stride;
110  }
111  data++;
112  break;
113  case 3: // raw block
114  for(y = 0; y < 4; y++){
115  memcpy(tmp, data, 4);
116  data += 4;
117  tmp += stride;
118  }
119  break;
120  case 8: // subblocks - method 13 only
121  mask = *msk++;
122  for(k = 0; k < 4; k++){
123  d = ((k & 1) << 1) + ((k & 2) * stride);
124  d2 = ((k & 1) << 1) + ((k & 2) * stride);
125  tmp2 = ref + i + d2;
126  switch(mask & 0xC0){
127  case 0x80: // motion compensation
128  x = (*mv) >> 4; if(x & 8) x = 8 - x;
129  y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
130  tmp2 += x + y*stride;
131  case 0x00: // skip
132  tmp[d + 0 ] = tmp2[0];
133  tmp[d + 1 ] = tmp2[1];
134  tmp[d + 0 + stride] = tmp2[0 + stride];
135  tmp[d + 1 + stride] = tmp2[1 + stride];
136  break;
137  case 0x40: // fill
138  tmp[d + 0 ] = data[0];
139  tmp[d + 1 ] = data[0];
140  tmp[d + 0 + stride] = data[0];
141  tmp[d + 1 + stride] = data[0];
142  data++;
143  break;
144  case 0xC0: // raw
145  tmp[d + 0 ] = *data++;
146  tmp[d + 1 ] = *data++;
147  tmp[d + 0 + stride] = *data++;
148  tmp[d + 1 + stride] = *data++;
149  break;
150  }
151  mask <<= 2;
152  }
153  break;
154  case 32: // vector quantization - 2 colors
155  mask = AV_RB16(msk);
156  msk += 2;
157  for(y = 0; y < 4; y++){
158  for(x = 0; x < 4; x++){
159  tmp[x] = data[mask & 1];
160  mask >>= 1;
161  }
162  tmp += stride;
163  tmp2 += stride;
164  }
165  data += 2;
166  break;
167  case 33: // vector quantization - 3 or 4 colors
168  case 34:
169  mask = AV_RB32(msk);
170  msk += 4;
171  for(y = 0; y < 4; y++){
172  for(x = 0; x < 4; x++){
173  tmp[x] = data[mask & 3];
174  mask >>= 2;
175  }
176  tmp += stride;
177  tmp2 += stride;
178  }
179  data += type - 30;
180  break;
181  default:
182  av_log(avctx, AV_LOG_ERROR, "Unknown opcode %d\n", type);
183  return -1;
184  }
185  }
186  dst += stride * 4;
187  ref += stride * 4;
188  }
189  return 0;
190 }
191 
192 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
193 {
194  const uint8_t *buf = avpkt->data;
195  int buf_size = avpkt->size;
196  DxaDecContext * const c = avctx->priv_data;
197  uint8_t *outptr, *srcptr, *tmpptr;
198  unsigned long dsize;
199  int i, j, compr;
200  int stride;
201  int orig_buf_size = buf_size;
202  int pc = 0;
203 
204  /* make the palette available on the way out */
205  if(buf[0]=='C' && buf[1]=='M' && buf[2]=='A' && buf[3]=='P'){
206  int r, g, b;
207 
208  buf += 4;
209  for(i = 0; i < 256; i++){
210  r = *buf++;
211  g = *buf++;
212  b = *buf++;
213  c->pal[i] = (r << 16) | (g << 8) | b;
214  }
215  pc = 1;
216  buf_size -= 768+4;
217  }
218 
219  if(ff_get_buffer(avctx, &c->pic) < 0){
220  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
221  return -1;
222  }
223  memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
224  c->pic.palette_has_changed = pc;
225 
226  outptr = c->pic.data[0];
227  srcptr = c->decomp_buf;
228  tmpptr = c->prev.data[0];
229  stride = c->pic.linesize[0];
230 
231  if(buf[0]=='N' && buf[1]=='U' && buf[2]=='L' && buf[3]=='L')
232  compr = -1;
233  else
234  compr = buf[4];
235 
236  dsize = c->dsize;
237  if((compr != 4 && compr != -1) && uncompress(c->decomp_buf, &dsize, buf + 9, buf_size - 9) != Z_OK){
238  av_log(avctx, AV_LOG_ERROR, "Uncompress failed!\n");
239  return -1;
240  }
241  switch(compr){
242  case -1:
243  c->pic.key_frame = 0;
245  if(c->prev.data[0])
246  memcpy(c->pic.data[0], c->prev.data[0], c->pic.linesize[0] * avctx->height);
247  else{ // Should happen only when first frame is 'NULL'
248  memset(c->pic.data[0], 0, c->pic.linesize[0] * avctx->height);
249  c->pic.key_frame = 1;
251  }
252  break;
253  case 2:
254  case 3:
255  case 4:
256  case 5:
257  c->pic.key_frame = !(compr & 1);
258  c->pic.pict_type = (compr & 1) ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;
259 
260  if (!tmpptr && !c->pic.key_frame) {
261  av_log(avctx, AV_LOG_ERROR, "Missing reference frame.\n");
262  return AVERROR_INVALIDDATA;
263  }
264 
265  for(j = 0; j < avctx->height; j++){
266  if(compr & 1){
267  for(i = 0; i < avctx->width; i++)
268  outptr[i] = srcptr[i] ^ tmpptr[i];
269  tmpptr += stride;
270  }else
271  memcpy(outptr, srcptr, avctx->width);
272  outptr += stride;
273  srcptr += avctx->width;
274  }
275  break;
276  case 12: // ScummVM coding
277  case 13:
278  c->pic.key_frame = 0;
280  decode_13(avctx, c, c->pic.data[0], srcptr, c->prev.data[0]);
281  break;
282  default:
283  av_log(avctx, AV_LOG_ERROR, "Unknown/unsupported compression type %d\n", buf[4]);
284  return -1;
285  }
286 
287  FFSWAP(AVFrame, c->pic, c->prev);
288  if(c->pic.data[0])
289  avctx->release_buffer(avctx, &c->pic);
290 
291  *got_frame = 1;
292  *(AVFrame*)data = c->prev;
293 
294  /* always report that the buffer was completely consumed */
295  return orig_buf_size;
296 }
297 
299 {
300  DxaDecContext * const c = avctx->priv_data;
301 
302  avctx->pix_fmt = AV_PIX_FMT_PAL8;
303 
304  c->dsize = avctx->width * avctx->height * 2;
305  if((c->decomp_buf = av_malloc(c->dsize)) == NULL) {
306  av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
307  return -1;
308  }
309 
310  return 0;
311 }
312 
314 {
315  DxaDecContext * const c = avctx->priv_data;
316 
317  av_freep(&c->decomp_buf);
318  if(c->prev.data[0])
319  avctx->release_buffer(avctx, &c->prev);
320  if(c->pic.data[0])
321  avctx->release_buffer(avctx, &c->pic);
322 
323  return 0;
324 }
325 
327  .name = "dxa",
328  .type = AVMEDIA_TYPE_VIDEO,
329  .id = AV_CODEC_ID_DXA,
330  .priv_data_size = sizeof(DxaDecContext),
331  .init = decode_init,
332  .close = decode_end,
333  .decode = decode_frame,
334  .capabilities = CODEC_CAP_DR1,
335  .long_name = NULL_IF_CONFIG_SMALL("Feeble Files/ScummVM DXA"),
336 };