vb.c
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1 /*
2  * Beam Software VB 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 "avcodec.h"
31 #include "bytestream.h"
32 
33 enum VBFlags{
34  VB_HAS_GMC = 0x01,
35  VB_HAS_AUDIO = 0x04,
36  VB_HAS_VIDEO = 0x08,
39 };
40 
41 typedef struct VBDecContext {
44 
45  uint8_t *frame, *prev_frame;
46  uint32_t pal[AVPALETTE_COUNT];
48 } VBDecContext;
49 
50 static const uint16_t vb_patterns[64] = {
51  0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,
52  0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,
53  0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,
54  0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,
55  0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,
56  0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,
57  0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,
58  0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C
59 };
60 
61 static void vb_decode_palette(VBDecContext *c, int data_size)
62 {
63  int start, size, i;
64 
65  start = bytestream2_get_byte(&c->stream);
66  size = (bytestream2_get_byte(&c->stream) - 1) & 0xFF;
67  if(start + size > 255){
68  av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");
69  return;
70  }
71  if(size*3+2 > data_size){
72  av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");
73  return;
74  }
75  for(i = start; i <= start + size; i++)
76  c->pal[i] = bytestream2_get_be24(&c->stream);
77 }
78 
79 static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
80 {
81  return buf >= start && buf < end;
82 }
83 
84 static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
85 {
86  return buf >= start && (buf + 4) <= end;
87 }
88 
89 static int vb_decode_framedata(VBDecContext *c, int offset)
90 {
92  uint8_t *prev, *cur;
93  int blk, blocks, t, blk2;
94  int blocktypes = 0;
95  int x, y, a, b;
96  int pattype, pattern;
97  const int width = c->avctx->width;
98  uint8_t *pstart = c->prev_frame;
99  uint8_t *pend = c->prev_frame + width*c->avctx->height;
100 
101  g = c->stream;
102 
103  prev = c->prev_frame + offset;
104  cur = c->frame;
105 
106  blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
107  blk2 = 0;
108  for(blk = 0; blk < blocks; blk++){
109  if(!(blk & 3)) {
110  blocktypes = bytestream2_get_byte(&g);
111  }
112  switch(blocktypes & 0xC0){
113  case 0x00: //skip
114  for(y = 0; y < 4; y++)
115  if(check_line(prev + y*width, pstart, pend))
116  memcpy(cur + y*width, prev + y*width, 4);
117  else
118  memset(cur + y*width, 0, 4);
119  break;
120  case 0x40:
121  t = bytestream2_get_byte(&g);
122  if(!t){ //raw block
123  if (bytestream2_get_bytes_left(&g) < 16) {
124  av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
125  return -1;
126  }
127  for(y = 0; y < 4; y++)
128  bytestream2_get_buffer(&g, cur + y * width, 4);
129  }else{ // motion compensation
130  x = ((t & 0xF)^8) - 8;
131  y = ((t >> 4) ^8) - 8;
132  t = x + y*width;
133  for(y = 0; y < 4; y++)
134  if(check_line(prev + t + y*width, pstart, pend))
135  memcpy(cur + y*width, prev + t + y*width, 4);
136  else
137  memset(cur + y*width, 0, 4);
138  }
139  break;
140  case 0x80: // fill
141  t = bytestream2_get_byte(&g);
142  for(y = 0; y < 4; y++)
143  memset(cur + y*width, t, 4);
144  break;
145  case 0xC0: // pattern fill
146  t = bytestream2_get_byte(&g);
147  pattype = t >> 6;
148  pattern = vb_patterns[t & 0x3F];
149  switch(pattype){
150  case 0:
151  a = bytestream2_get_byte(&g);
152  b = bytestream2_get_byte(&g);
153  for(y = 0; y < 4; y++)
154  for(x = 0; x < 4; x++, pattern >>= 1)
155  cur[x + y*width] = (pattern & 1) ? b : a;
156  break;
157  case 1:
158  pattern = ~pattern;
159  case 2:
160  a = bytestream2_get_byte(&g);
161  for(y = 0; y < 4; y++)
162  for(x = 0; x < 4; x++, pattern >>= 1)
163  if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
164  cur[x + y*width] = prev[x + y*width];
165  else
166  cur[x + y*width] = a;
167  break;
168  case 3:
169  av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
170  return -1;
171  }
172  break;
173  }
174  blocktypes <<= 2;
175  cur += 4;
176  prev += 4;
177  blk2++;
178  if(blk2 == (width >> 2)){
179  blk2 = 0;
180  cur += width * 3;
181  prev += width * 3;
182  }
183  }
184  return 0;
185 }
186 
187 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
188 {
189  VBDecContext * const c = avctx->priv_data;
190  uint8_t *outptr, *srcptr;
191  int i, j;
192  int flags;
193  uint32_t size;
194  int offset = 0;
195 
196  bytestream2_init(&c->stream, avpkt->data, avpkt->size);
197 
198  if(c->pic.data[0])
199  avctx->release_buffer(avctx, &c->pic);
200  c->pic.reference = 1;
201  if(avctx->get_buffer(avctx, &c->pic) < 0){
202  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
203  return -1;
204  }
205 
206  flags = bytestream2_get_le16(&c->stream);
207 
208  if(flags & VB_HAS_GMC){
209  i = (int16_t)bytestream2_get_le16(&c->stream);
210  j = (int16_t)bytestream2_get_le16(&c->stream);
211  offset = i + j * avctx->width;
212  }
213  if(flags & VB_HAS_VIDEO){
214  size = bytestream2_get_le32(&c->stream);
215  vb_decode_framedata(c, offset);
216  bytestream2_skip(&c->stream, size - 4);
217  }
218  if(flags & VB_HAS_PALETTE){
219  size = bytestream2_get_le32(&c->stream);
220  vb_decode_palette(c, size);
221  }
222 
223  memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
225 
226  outptr = c->pic.data[0];
227  srcptr = c->frame;
228 
229  for(i = 0; i < avctx->height; i++){
230  memcpy(outptr, srcptr, avctx->width);
231  srcptr += avctx->width;
232  outptr += c->pic.linesize[0];
233  }
234 
235  FFSWAP(uint8_t*, c->frame, c->prev_frame);
236 
237  *data_size = sizeof(AVFrame);
238  *(AVFrame*)data = c->pic;
239 
240  /* always report that the buffer was completely consumed */
241  return avpkt->size;
242 }
243 
245 {
246  VBDecContext * const c = avctx->priv_data;
247 
248  c->avctx = avctx;
249  avctx->pix_fmt = PIX_FMT_PAL8;
250 
251  c->frame = av_mallocz(avctx->width * avctx->height);
252  c->prev_frame = av_mallocz(avctx->width * avctx->height);
253 
254  return 0;
255 }
256 
258 {
259  VBDecContext *c = avctx->priv_data;
260 
261  av_freep(&c->frame);
262  av_freep(&c->prev_frame);
263  if(c->pic.data[0])
264  avctx->release_buffer(avctx, &c->pic);
265 
266  return 0;
267 }
268 
270  .name = "vb",
271  .type = AVMEDIA_TYPE_VIDEO,
272  .id = CODEC_ID_VB,
273  .priv_data_size = sizeof(VBDecContext),
274  .init = decode_init,
275  .close = decode_end,
276  .decode = decode_frame,
277  .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
278 };
279