libavcodec/eatgv.c

   1 /*
   2  * Electronic Arts TGV Video Decoder
   3  * Copyright (c) 2007-2008 Peter Ross
   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 St, Fifth Floor, Boston, MA  02110-1301  USA
  20  */
  21
  22 /**
  23  * @file libavcodec/eatgv.c
  24  * Electronic Arts TGV Video Decoder
  25  * by Peter Ross (suxen_drol at hotmail dot com)
  26  *
  27  * Technical details here:
  28  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
  29  */
  30
  31 #include "avcodec.h"
  32 #define ALT_BITSTREAM_READER_LE
  33 #include "bitstream.h"
  34 #include "libavutil/lzo.h"
  35
  36 #define EA_PREAMBLE_SIZE    8
  37 #define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
  38
  39 typedef struct TgvContext {
  40     AVCodecContext *avctx;
  41     AVFrame frame;
  42     AVFrame last_frame;
  43     int width,height;
  44     unsigned int palette[AVPALETTE_COUNT];
  45
  46     int (*mv_codebook)[2];
  47     unsigned char (*block_codebook)[16];
  48     int num_mvs;           ///< current length of mv_codebook
  49     int num_blocks_packed; ///< current length of block_codebook
  50 } TgvContext;
  51
  52 static av_cold int tgv_decode_init(AVCodecContext *avctx){
  53     TgvContext *s = avctx->priv_data;
  54     s->avctx = avctx;
  55     avctx->time_base = (AVRational){1, 15};
  56     avctx->pix_fmt = PIX_FMT_PAL8;
  57     return 0;
  58 }
  59
  60 /**
  61  * Unpack buffer
  62  * @return 0 on success, -1 on critical buffer underflow
  63  */
  64 static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
  65     unsigned char *dst_end = dst + width*height;
  66     int size, size1, size2, av_uninit(offset), run;
  67     unsigned char *dst_start = dst;
  68
  69     if (src[0] & 0x01)
  70         src += 5;
  71     else
  72         src += 2;
  73
  74     if (src+3>src_end)
  75         return -1;
  76     size = AV_RB24(src);
  77     src += 3;
  78
  79     while(size>0 && src<src_end) {
  80
  81         /* determine size1 and size2 */
  82         size1 = (src[0] & 3);
  83         if ( src[0] & 0x80 ) {  // 1
  84             if (src[0] & 0x40 ) {  // 11
  85                 if ( src[0] & 0x20 ) {  // 111
  86                     if ( src[0] < 0xFC )  // !(111111)
  87                         size1 = (((src[0] & 31) + 1) << 2);
  88                     src++;
  89                     size2 = 0;
  90                 } else {  // 110
  91                     offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
  92                     size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
  93                     src += 4;
  94                 }
  95             } else {  // 10
  96                 size1 = ( ( src[1] & 0xC0) >> 6 );
  97                 offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
  98                 size2 = (src[0] & 0x3F) + 4;
  99                 src += 3;
 100             }
 101         } else {  // 0
 102             offset = ((src[0] & 0x60) << 3) + src[1] + 1;
 103             size2 = ((src[0] & 0x1C) >> 2) + 3;
 104             src += 2;
 105         }
 106
 107
 108         /* fetch strip from src */
 109         if (size1>src_end-src)
 110             break;
 111
 112         if (size1>0) {
 113             size -= size1;
 114             run = FFMIN(size1, dst_end-dst);
 115             memcpy(dst, src, run);
 116             dst += run;
 117             src += run;
 118         }
 119
 120         if (size2>0) {
 121             if (dst-dst_start<offset)
 122                 return 0;
 123             size -= size2;
 124             run = FFMIN(size2, dst_end-dst);
 125             av_memcpy_backptr(dst, offset, run);
 126             dst += run;
 127         }
 128     }
 129
 130     return 0;
 131 }
 132
 133 /**
 134  * Decode inter-frame
 135  * @return 0 on success, -1 on critical buffer underflow
 136  */
 137 static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
 138     unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
 139     int num_mvs;
 140     int num_blocks_raw;
 141     int num_blocks_packed;
 142     int vector_bits;
 143     int i,j,x,y;
 144     GetBitContext gb;
 145     int mvbits;
 146     const unsigned char *blocks_raw;
 147
 148     if(buf+12>buf_end)
 149         return -1;
 150
 151     num_mvs           = AV_RL16(&buf[0]);
 152     num_blocks_raw    = AV_RL16(&buf[2]);
 153     num_blocks_packed = AV_RL16(&buf[4]);
 154     vector_bits       = AV_RL16(&buf[6]);
 155     buf += 12;
 156
 157     /* allocate codebook buffers as neccessary */
 158     if (num_mvs > s->num_mvs) {
 159         s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
 160         s->num_mvs = num_mvs;
 161     }
 162
 163     if (num_blocks_packed > s->num_blocks_packed) {
 164         s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
 165         s->num_blocks_packed = num_blocks_packed;
 166     }
 167
 168     /* read motion vectors */
 169     mvbits = (num_mvs*2*10+31) & ~31;
 170
 171     if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
 172         return -1;
 173
 174     init_get_bits(&gb, buf, mvbits);
 175     for (i=0; i<num_mvs; i++) {
 176         s->mv_codebook[i][0] = get_sbits(&gb, 10);
 177         s->mv_codebook[i][1] = get_sbits(&gb, 10);
 178     }
 179     buf += mvbits>>3;
 180
 181     /* note ptr to uncompressed blocks */
 182     blocks_raw = buf;
 183     buf += num_blocks_raw*16;
 184
 185     /* read compressed blocks */
 186     init_get_bits(&gb, buf, (buf_end-buf)<<3);
 187     for (i=0; i<num_blocks_packed; i++) {
 188         int tmp[4];
 189         for(j=0; j<4; j++)
 190             tmp[j] = get_bits(&gb, 8);
 191         for(j=0; j<16; j++)
 192             s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
 193     }
 194
 195     /* read vectors and build frame */
 196     for(y=0; y<s->avctx->height/4; y++)
 197     for(x=0; x<s->avctx->width/4; x++) {
 198         unsigned int vector = get_bits(&gb, vector_bits);
 199         const unsigned char *src;
 200         int src_stride;
 201
 202         if (vector < num_mvs) {
 203             src = s->last_frame.data[0] +
 204                   (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
 205                    x*4 + s->mv_codebook[vector][0];
 206             src_stride = s->last_frame.linesize[0];
 207             if (src+3*src_stride+3>=frame0_end)
 208                 continue;
 209         }else{
 210             int offset = vector - num_mvs;
 211             if (offset<num_blocks_raw)
 212                 src = blocks_raw + 16*offset;
 213             else if (offset-num_blocks_raw<num_blocks_packed)
 214                 src = s->block_codebook[offset-num_blocks_raw];
 215             else
 216                 continue;
 217             src_stride = 4;
 218         }
 219
 220         for(j=0; j<4; j++)
 221         for(i=0; i<4; i++)
 222             s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i)  ] =
 223                src[j*src_stride + i];
 224     }
 225
 226     return 0;
 227 }
 228
 229 /** release AVFrame buffers if allocated */
 230 static void cond_release_buffer(AVFrame *pic)
 231 {
 232     if (pic->data[0]) {
 233         av_freep(&pic->data[0]);
 234         av_free(pic->data[1]);
 235     }
 236 }
 237
 238 static int tgv_decode_frame(AVCodecContext *avctx,
 239                             void *data, int *data_size,
 240                             const uint8_t *buf, int buf_size)
 241 {
 242     TgvContext *s = avctx->priv_data;
 243     const uint8_t *buf_end = buf + buf_size;
 244     int chunk_type;
 245
 246     chunk_type = AV_RL32(&buf[0]);
 247     buf += EA_PREAMBLE_SIZE;
 248
 249     if (chunk_type==kVGT_TAG) {
 250         int pal_count, i;
 251         if(buf+12>buf_end) {
 252             av_log(avctx, AV_LOG_WARNING, "truncated header\n");
 253             return -1;
 254         }
 255
 256         s->width  = AV_RL16(&buf[0]);
 257         s->height = AV_RL16(&buf[2]);
 258         if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
 259             avcodec_set_dimensions(s->avctx, s->width, s->height);
 260             cond_release_buffer(&s->frame);
 261             cond_release_buffer(&s->last_frame);
 262         }
 263
 264         pal_count = AV_RL16(&buf[6]);
 265         buf += 12;
 266         for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
 267             s->palette[i] = AV_RB24(buf);
 268             buf += 3;
 269         }
 270     }
 271
 272     if (avcodec_check_dimensions(avctx, s->width, s->height))
 273         return -1;
 274
 275     /* shuffle */
 276     FFSWAP(AVFrame, s->frame, s->last_frame);
 277     if (!s->frame.data[0]) {
 278         s->frame.reference = 1;
 279         s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 280         s->frame.linesize[0] = s->width;
 281
 282         /* allocate additional 12 bytes to accomodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
 283         s->frame.data[0] = av_malloc(s->width*s->height + 12);
 284         if (!s->frame.data[0])
 285             return AVERROR_NOMEM;
 286         s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
 287         if (!s->frame.data[1]) {
 288             av_freep(&s->frame.data[0]);
 289             return AVERROR_NOMEM;
 290         }
 291     }
 292     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 293
 294     if(chunk_type==kVGT_TAG) {
 295         s->frame.key_frame = 1;
 296         s->frame.pict_type = FF_I_TYPE;
 297         if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
 298             av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
 299             return -1;
 300         }
 301     }else{
 302         if (!s->last_frame.data[0]) {
 303             av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
 304             return buf_size;
 305         }
 306         s->frame.key_frame = 0;
 307         s->frame.pict_type = FF_P_TYPE;
 308         if (tgv_decode_inter(s, buf, buf_end)<0) {
 309             av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
 310             return -1;
 311         }
 312     }
 313
 314     *data_size = sizeof(AVFrame);
 315     *(AVFrame*)data = s->frame;
 316
 317     return buf_size;
 318 }
 319
 320 static av_cold int tgv_decode_end(AVCodecContext *avctx)
 321 {
 322     TgvContext *s = avctx->priv_data;
 323     cond_release_buffer(&s->frame);
 324     cond_release_buffer(&s->last_frame);
 325     av_free(s->mv_codebook);
 326     av_free(s->block_codebook);
 327     return 0;
 328 }
 329
 330 AVCodec eatgv_decoder = {
 331     "eatgv",
 332     CODEC_TYPE_VIDEO,
 333     CODEC_ID_TGV,
 334     sizeof(TgvContext),
 335     tgv_decode_init,
 336     NULL,
 337     tgv_decode_end,
 338     tgv_decode_frame,
 339     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
 340 };