libavcodec/vb.c

   1 /*
   2  * Beam Software VB decoder
   3  * Copyright (c) 2007 Konstantin Shishkov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file vb.c
  24  * VB Video decoder
  25  */
  26
  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,
  37     VB_HAS_PALETTE = 0x10,
  38     VB_HAS_LENGTH  = 0x20
  39 };
  40
  41 typedef struct VBDecContext {
  42     AVCodecContext *avctx;
  43     AVFrame pic;
  44
  45     uint8_t *frame, *prev_frame;
  46     uint32_t pal[256];
  47     const uint8_t *stream;
  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)
  62 {
  63     int start, size, i;
  64
  65     start = bytestream_get_byte(&c->stream);
  66     size = (bytestream_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     for(i = start; i <= start + size; i++)
  72         c->pal[i] = bytestream_get_be24(&c->stream);
  73 }
  74
  75 static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
  76 {
  77     return buf >= start && buf < end;
  78 }
  79
  80 static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
  81 {
  82     return buf >= start && (buf + 4) <= end;
  83 }
  84
  85 static int vb_decode_framedata(VBDecContext *c, const uint8_t *buf, int offset)
  86 {
  87     uint8_t *prev, *cur;
  88     int blk, blocks, t, blk2;
  89     int blocktypes = 0;
  90     int x, y, a, b;
  91     int pattype, pattern;
  92     const int width = c->avctx->width;
  93     uint8_t *pstart = c->prev_frame;
  94     uint8_t *pend = c->prev_frame + width*c->avctx->height;
  95
  96     prev = c->prev_frame + offset;
  97     cur = c->frame;
  98
  99     blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
 100     blk2 = 0;
 101     for(blk = 0; blk < blocks; blk++){
 102         if(!(blk & 3))
 103             blocktypes = bytestream_get_byte(&buf);
 104         switch(blocktypes & 0xC0){
 105         case 0x00: //skip
 106             for(y = 0; y < 4; y++)
 107                 if(check_line(prev + y*width, pstart, pend))
 108                     memcpy(cur + y*width, prev + y*width, 4);
 109                 else
 110                     memset(cur + y*width, 0, 4);
 111             break;
 112         case 0x40:
 113             t = bytestream_get_byte(&buf);
 114             if(!t){ //raw block
 115                 for(y = 0; y < 4; y++)
 116                     memcpy(cur + y*width, buf + y*4, 4);
 117                 buf += 16;
 118             }else{ // motion compensation
 119                 x = ((t & 0xF)^8) - 8;
 120                 y = ((t >> 4) ^8) - 8;
 121                 t = x + y*width;
 122                 for(y = 0; y < 4; y++)
 123                     if(check_line(prev + t + y*width, pstart, pend))
 124                         memcpy(cur + y*width, prev + t + y*width, 4);
 125                     else
 126                         memset(cur + y*width, 0, 4);
 127             }
 128             break;
 129         case 0x80: // fill
 130             t = bytestream_get_byte(&buf);
 131             for(y = 0; y < 4; y++)
 132                 memset(cur + y*width, t, 4);
 133             break;
 134         case 0xC0: // pattern fill
 135             t = bytestream_get_byte(&buf);
 136             pattype = t >> 6;
 137             pattern = vb_patterns[t & 0x3F];
 138             switch(pattype){
 139             case 0:
 140                 a = bytestream_get_byte(&buf);
 141                 b = bytestream_get_byte(&buf);
 142                 for(y = 0; y < 4; y++)
 143                     for(x = 0; x < 4; x++, pattern >>= 1)
 144                         cur[x + y*width] = (pattern & 1) ? b : a;
 145                 break;
 146             case 1:
 147                 pattern = ~pattern;
 148             case 2:
 149                 a = bytestream_get_byte(&buf);
 150                 for(y = 0; y < 4; y++)
 151                     for(x = 0; x < 4; x++, pattern >>= 1)
 152                         if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
 153                             cur[x + y*width] = prev[x + y*width];
 154                         else
 155                             cur[x + y*width] = a;
 156                 break;
 157             case 3:
 158                 av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
 159                 return -1;
 160             }
 161             break;
 162         }
 163         blocktypes <<= 2;
 164         cur  += 4;
 165         prev += 4;
 166         blk2++;
 167         if(blk2 == (width >> 2)){
 168             blk2 = 0;
 169             cur  += width * 3;
 170             prev += width * 3;
 171         }
 172     }
 173     return 0;
 174 }
 175
 176 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
 177 {
 178     VBDecContext * const c = avctx->priv_data;
 179     uint8_t *outptr, *srcptr;
 180     int i, j;
 181     int flags;
 182     uint32_t size;
 183     int rest = buf_size;
 184     int offset = 0;
 185
 186     c->stream = buf;
 187     flags = bytestream_get_le16(&c->stream);
 188     rest -= 2;
 189
 190     if(flags & VB_HAS_GMC){
 191         i = (int16_t)bytestream_get_le16(&c->stream);
 192         j = (int16_t)bytestream_get_le16(&c->stream);
 193         offset = i + j * avctx->width;
 194         rest -= 4;
 195     }
 196     if(flags & VB_HAS_VIDEO){
 197         size = bytestream_get_le32(&c->stream);
 198         if(size > rest){
 199             av_log(avctx, AV_LOG_ERROR, "Frame size is too big\n");
 200             return -1;
 201         }
 202         vb_decode_framedata(c, c->stream, offset);
 203         c->stream += size - 4;
 204         rest -= size;
 205     }
 206     if(flags & VB_HAS_PALETTE){
 207         size = bytestream_get_le32(&c->stream);
 208         if(size > rest){
 209             av_log(avctx, AV_LOG_ERROR, "Palette size is too big\n");
 210             return -1;
 211         }
 212         vb_decode_palette(c);
 213         rest -= size;
 214     }
 215
 216     memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
 217     c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
 218
 219     outptr = c->pic.data[0];
 220     srcptr = c->frame;
 221
 222     for(i = 0; i < avctx->height; i++){
 223         memcpy(outptr, srcptr, avctx->width);
 224         srcptr += avctx->width;
 225         outptr += c->pic.linesize[0];
 226     }
 227
 228     FFSWAP(uint8_t*, c->frame, c->prev_frame);
 229
 230     *data_size = sizeof(AVFrame);
 231     *(AVFrame*)data = c->pic;
 232
 233     /* always report that the buffer was completely consumed */
 234     return buf_size;
 235 }
 236
 237 static av_cold int decode_init(AVCodecContext *avctx)
 238 {
 239     VBDecContext * const c = avctx->priv_data;
 240
 241     c->avctx = avctx;
 242     avctx->pix_fmt = PIX_FMT_PAL8;
 243
 244     if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
 245         return -1;
 246     }
 247
 248     c->pic.reference = 1;
 249     if(avctx->get_buffer(avctx, &c->pic) < 0){
 250         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 251         return -1;
 252     }
 253
 254     c->frame      = av_malloc( avctx->width * avctx->height);
 255     c->prev_frame = av_malloc( avctx->width * avctx->height);
 256
 257     return 0;
 258 }
 259
 260 static av_cold int decode_end(AVCodecContext *avctx)
 261 {
 262     VBDecContext *c = avctx->priv_data;
 263
 264     av_freep(&c->frame);
 265     av_freep(&c->prev_frame);
 266     if(c->pic.data[0])
 267         avctx->release_buffer(avctx, &c->pic);
 268
 269     return 0;
 270 }
 271
 272 AVCodec vb_decoder = {
 273     "vb",
 274     CODEC_TYPE_VIDEO,
 275     CODEC_ID_VB,
 276     sizeof(VBDecContext),
 277     decode_init,
 278     NULL,
 279     decode_end,
 280     decode_frame,
 281     .long_name = "Beam Software VB",
 282 };
 283