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 libavcodec/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 33enum 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 41typedef 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 50static 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 61static 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 75static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end) 76{ 77 return buf >= start && buf < end; 78} 79 80static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end) 81{ 82 return buf >= start && (buf + 4) <= end; 83} 84 85static 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 176static 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 237static 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 260static 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 272AVCodec 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 = NULL_IF_CONFIG_SMALL("Beam Software VB"), 282}; 283 284