libavcodec/eatgv.c

   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
  22 /**
  23  * @file
  24  * Electronic Arts TGV Video Decoder
  25  * by Peter Ross (pross@xvid.org)
  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 "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 {
  41     AVCodecContext *avctx;
  42     AVFrame frame;
  43     AVFrame last_frame;
  44     int width,height;
  45     unsigned int palette[AVPALETTE_COUNT];
  46
  47     int (*mv_codebook)[2];
  48     unsigned char (*block_codebook)[16];
  49     int num_mvs;           ///< current length of mv_codebook
  50     int num_blocks_packed; ///< current length of block_codebook
  51 } TgvContext;
  52
  53 static av_cold int tgv_decode_init(AVCodecContext *avctx){
  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
  61 /**
  62  * Unpack buffer
  63  * @return 0 on success, -1 on critical buffer underflow
  64  */
  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
 134 /**
 135  * Decode inter-frame
 136  * @return 0 on success, -1 on critical buffer underflow
 137  */
 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 neccessary */
 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
 234 /** release AVFrame buffers if allocated */
 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
 243 static int tgv_decode_frame(AVCodecContext *avctx,
 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) {
 266             avcodec_set_dimensions(s->avctx, s->width, s->height);
 267             cond_release_buffer(&s->frame);
 268             cond_release_buffer(&s->last_frame);
 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;
 286         s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
 287         s->frame.linesize[0] = s->width;
 288
 289         /* allocate additional 12 bytes to accomodate 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);
 293         s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
 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;
 303         s->frame.pict_type = AV_PICTURE_TYPE_I;
 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;
 314         s->frame.pict_type = AV_PICTURE_TYPE_P;
 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
 327 static av_cold int tgv_decode_end(AVCodecContext *avctx)
 328 {
 329     TgvContext *s = avctx->priv_data;
 330     cond_release_buffer(&s->frame);
 331     cond_release_buffer(&s->last_frame);
 332     av_free(s->mv_codebook);
 333     av_free(s->block_codebook);
 334     return 0;
 335 }
 336
 337 AVCodec ff_eatgv_decoder = {
 338     .name           = "eatgv",
 339     .type           = AVMEDIA_TYPE_VIDEO,
 340     .id             = CODEC_ID_TGV,
 341     .priv_data_size = sizeof(TgvContext),
 342     .init           = tgv_decode_init,
 343     .close          = tgv_decode_end,
 344     .decode         = tgv_decode_frame,
 345     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
 346 };