eatgv.c
Go to the documentation of this file.
1 /*
2  * Electronic Arts TGV Video Decoder
3  * Copyright (c) 2007-2008 Peter Ross
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 St, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
31 #include "avcodec.h"
32 #define BITSTREAM_READER_LE
33 #include "get_bits.h"
34 #include "libavutil/lzo.h"
35 #include "libavutil/imgutils.h"
36 
37 #define EA_PREAMBLE_SIZE 8
38 #define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
39 
40 typedef struct TgvContext {
45  unsigned int palette[AVPALETTE_COUNT];
46 
47  int (*mv_codebook)[2];
48  unsigned char (*block_codebook)[16];
49  int num_mvs;
51 } TgvContext;
52 
54  TgvContext *s = avctx->priv_data;
55  s->avctx = avctx;
56  avctx->time_base = (AVRational){1, 15};
57  avctx->pix_fmt = PIX_FMT_PAL8;
58  return 0;
59 }
60 
65 static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
66  unsigned char *dst_end = dst + width*height;
67  int size, size1, size2, av_uninit(offset), run;
68  unsigned char *dst_start = dst;
69 
70  if (src[0] & 0x01)
71  src += 5;
72  else
73  src += 2;
74 
75  if (src+3>src_end)
76  return -1;
77  size = AV_RB24(src);
78  src += 3;
79 
80  while(size>0 && src<src_end) {
81 
82  /* determine size1 and size2 */
83  size1 = (src[0] & 3);
84  if ( src[0] & 0x80 ) { // 1
85  if (src[0] & 0x40 ) { // 11
86  if ( src[0] & 0x20 ) { // 111
87  if ( src[0] < 0xFC ) // !(111111)
88  size1 = (((src[0] & 31) + 1) << 2);
89  src++;
90  size2 = 0;
91  } else { // 110
92  offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
93  size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
94  src += 4;
95  }
96  } else { // 10
97  size1 = ( ( src[1] & 0xC0) >> 6 );
98  offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
99  size2 = (src[0] & 0x3F) + 4;
100  src += 3;
101  }
102  } else { // 0
103  offset = ((src[0] & 0x60) << 3) + src[1] + 1;
104  size2 = ((src[0] & 0x1C) >> 2) + 3;
105  src += 2;
106  }
107 
108 
109  /* fetch strip from src */
110  if (size1>src_end-src)
111  break;
112 
113  if (size1>0) {
114  size -= size1;
115  run = FFMIN(size1, dst_end-dst);
116  memcpy(dst, src, run);
117  dst += run;
118  src += run;
119  }
120 
121  if (size2>0) {
122  if (dst-dst_start<offset)
123  return 0;
124  size -= size2;
125  run = FFMIN(size2, dst_end-dst);
126  av_memcpy_backptr(dst, offset, run);
127  dst += run;
128  }
129  }
130 
131  return 0;
132 }
133 
138 static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
139  unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
140  int num_mvs;
141  int num_blocks_raw;
142  int num_blocks_packed;
143  int vector_bits;
144  int i,j,x,y;
145  GetBitContext gb;
146  int mvbits;
147  const unsigned char *blocks_raw;
148 
149  if(buf+12>buf_end)
150  return -1;
151 
152  num_mvs = AV_RL16(&buf[0]);
153  num_blocks_raw = AV_RL16(&buf[2]);
154  num_blocks_packed = AV_RL16(&buf[4]);
155  vector_bits = AV_RL16(&buf[6]);
156  buf += 12;
157 
158  /* allocate codebook buffers as necessary */
159  if (num_mvs > s->num_mvs) {
160  s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
161  s->num_mvs = num_mvs;
162  }
163 
164  if (num_blocks_packed > s->num_blocks_packed) {
165  s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
166  s->num_blocks_packed = num_blocks_packed;
167  }
168 
169  /* read motion vectors */
170  mvbits = (num_mvs*2*10+31) & ~31;
171 
172  if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
173  return -1;
174 
175  init_get_bits(&gb, buf, mvbits);
176  for (i=0; i<num_mvs; i++) {
177  s->mv_codebook[i][0] = get_sbits(&gb, 10);
178  s->mv_codebook[i][1] = get_sbits(&gb, 10);
179  }
180  buf += mvbits>>3;
181 
182  /* note ptr to uncompressed blocks */
183  blocks_raw = buf;
184  buf += num_blocks_raw*16;
185 
186  /* read compressed blocks */
187  init_get_bits(&gb, buf, (buf_end-buf)<<3);
188  for (i=0; i<num_blocks_packed; i++) {
189  int tmp[4];
190  for(j=0; j<4; j++)
191  tmp[j] = get_bits(&gb, 8);
192  for(j=0; j<16; j++)
193  s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
194  }
195 
196  if (get_bits_left(&gb) < vector_bits *
197  (s->avctx->height/4) * (s->avctx->width/4))
198  return -1;
199 
200  /* read vectors and build frame */
201  for(y=0; y<s->avctx->height/4; y++)
202  for(x=0; x<s->avctx->width/4; x++) {
203  unsigned int vector = get_bits(&gb, vector_bits);
204  const unsigned char *src;
205  int src_stride;
206 
207  if (vector < num_mvs) {
208  src = s->last_frame.data[0] +
209  (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
210  x*4 + s->mv_codebook[vector][0];
211  src_stride = s->last_frame.linesize[0];
212  if (src+3*src_stride+3>=frame0_end)
213  continue;
214  }else{
215  int offset = vector - num_mvs;
216  if (offset<num_blocks_raw)
217  src = blocks_raw + 16*offset;
218  else if (offset-num_blocks_raw<num_blocks_packed)
219  src = s->block_codebook[offset-num_blocks_raw];
220  else
221  continue;
222  src_stride = 4;
223  }
224 
225  for(j=0; j<4; j++)
226  for(i=0; i<4; i++)
227  s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i) ] =
228  src[j*src_stride + i];
229  }
230 
231  return 0;
232 }
233 
235 static void cond_release_buffer(AVFrame *pic)
236 {
237  if (pic->data[0]) {
238  av_freep(&pic->data[0]);
239  av_free(pic->data[1]);
240  }
241 }
242 
244  void *data, int *data_size,
245  AVPacket *avpkt)
246 {
247  const uint8_t *buf = avpkt->data;
248  int buf_size = avpkt->size;
249  TgvContext *s = avctx->priv_data;
250  const uint8_t *buf_end = buf + buf_size;
251  int chunk_type;
252 
253  chunk_type = AV_RL32(&buf[0]);
254  buf += EA_PREAMBLE_SIZE;
255 
256  if (chunk_type==kVGT_TAG) {
257  int pal_count, i;
258  if(buf+12>buf_end) {
259  av_log(avctx, AV_LOG_WARNING, "truncated header\n");
260  return -1;
261  }
262 
263  s->width = AV_RL16(&buf[0]);
264  s->height = AV_RL16(&buf[2]);
265  if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
269  }
270 
271  pal_count = AV_RL16(&buf[6]);
272  buf += 12;
273  for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
274  s->palette[i] = AV_RB24(buf);
275  buf += 3;
276  }
277  }
278 
279  if (av_image_check_size(s->width, s->height, 0, avctx))
280  return -1;
281 
282  /* shuffle */
283  FFSWAP(AVFrame, s->frame, s->last_frame);
284  if (!s->frame.data[0]) {
285  s->frame.reference = 1;
287  s->frame.linesize[0] = s->width;
288 
289  /* allocate additional 12 bytes to accommodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
290  s->frame.data[0] = av_malloc(s->width*s->height + 12);
291  if (!s->frame.data[0])
292  return AVERROR(ENOMEM);
294  if (!s->frame.data[1]) {
295  av_freep(&s->frame.data[0]);
296  return AVERROR(ENOMEM);
297  }
298  }
299  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
300 
301  if(chunk_type==kVGT_TAG) {
302  s->frame.key_frame = 1;
304  if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
305  av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
306  return -1;
307  }
308  }else{
309  if (!s->last_frame.data[0]) {
310  av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
311  return buf_size;
312  }
313  s->frame.key_frame = 0;
315  if (tgv_decode_inter(s, buf, buf_end)<0) {
316  av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
317  return -1;
318  }
319  }
320 
321  *data_size = sizeof(AVFrame);
322  *(AVFrame*)data = s->frame;
323 
324  return buf_size;
325 }
326 
328 {
329  TgvContext *s = avctx->priv_data;
332  av_free(s->mv_codebook);
334  return 0;
335 }
336 
338  .name = "eatgv",
339  .type = AVMEDIA_TYPE_VIDEO,
340  .id = CODEC_ID_TGV,
341  .priv_data_size = sizeof(TgvContext),
345  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
346 };