libavcodec/eatgv.c
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00001 /*
00002  * Electronic Arts TGV Video Decoder
00003  * Copyright (c) 2007-2008 Peter Ross
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00020  */
00021 
00031 #include "avcodec.h"
00032 #define BITSTREAM_READER_LE
00033 #include "get_bits.h"
00034 #include "libavutil/lzo.h"
00035 #include "libavutil/imgutils.h"
00036 
00037 #define EA_PREAMBLE_SIZE    8
00038 #define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
00039 
00040 typedef struct TgvContext {
00041     AVCodecContext *avctx;
00042     AVFrame frame;
00043     AVFrame last_frame;
00044     int width,height;
00045     unsigned int palette[AVPALETTE_COUNT];
00046 
00047     int (*mv_codebook)[2];
00048     unsigned char (*block_codebook)[16];
00049     int num_mvs;           
00050     int num_blocks_packed; 
00051 } TgvContext;
00052 
00053 static av_cold int tgv_decode_init(AVCodecContext *avctx){
00054     TgvContext *s = avctx->priv_data;
00055     s->avctx = avctx;
00056     avctx->time_base = (AVRational){1, 15};
00057     avctx->pix_fmt = PIX_FMT_PAL8;
00058     return 0;
00059 }
00060 
00065 static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
00066     unsigned char *dst_end = dst + width*height;
00067     int size, size1, size2, av_uninit(offset), run;
00068     unsigned char *dst_start = dst;
00069 
00070     if (src[0] & 0x01)
00071         src += 5;
00072     else
00073         src += 2;
00074 
00075     if (src+3>src_end)
00076         return -1;
00077     size = AV_RB24(src);
00078     src += 3;
00079 
00080     while(size>0 && src<src_end) {
00081 
00082         /* determine size1 and size2 */
00083         size1 = (src[0] & 3);
00084         if ( src[0] & 0x80 ) {  // 1
00085             if (src[0] & 0x40 ) {  // 11
00086                 if ( src[0] & 0x20 ) {  // 111
00087                     if ( src[0] < 0xFC )  // !(111111)
00088                         size1 = (((src[0] & 31) + 1) << 2);
00089                     src++;
00090                     size2 = 0;
00091                 } else {  // 110
00092                     offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
00093                     size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
00094                     src += 4;
00095                 }
00096             } else {  // 10
00097                 size1 = ( ( src[1] & 0xC0) >> 6 );
00098                 offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
00099                 size2 = (src[0] & 0x3F) + 4;
00100                 src += 3;
00101             }
00102         } else {  // 0
00103             offset = ((src[0] & 0x60) << 3) + src[1] + 1;
00104             size2 = ((src[0] & 0x1C) >> 2) + 3;
00105             src += 2;
00106         }
00107 
00108 
00109         /* fetch strip from src */
00110         if (size1>src_end-src)
00111             break;
00112 
00113         if (size1>0) {
00114             size -= size1;
00115             run = FFMIN(size1, dst_end-dst);
00116             memcpy(dst, src, run);
00117             dst += run;
00118             src += run;
00119         }
00120 
00121         if (size2>0) {
00122             if (dst-dst_start<offset)
00123                 return 0;
00124             size -= size2;
00125             run = FFMIN(size2, dst_end-dst);
00126             av_memcpy_backptr(dst, offset, run);
00127             dst += run;
00128         }
00129     }
00130 
00131     return 0;
00132 }
00133 
00138 static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
00139     unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
00140     int num_mvs;
00141     int num_blocks_raw;
00142     int num_blocks_packed;
00143     int vector_bits;
00144     int i,j,x,y;
00145     GetBitContext gb;
00146     int mvbits;
00147     const unsigned char *blocks_raw;
00148 
00149     if(buf+12>buf_end)
00150         return -1;
00151 
00152     num_mvs           = AV_RL16(&buf[0]);
00153     num_blocks_raw    = AV_RL16(&buf[2]);
00154     num_blocks_packed = AV_RL16(&buf[4]);
00155     vector_bits       = AV_RL16(&buf[6]);
00156     buf += 12;
00157 
00158     /* allocate codebook buffers as necessary */
00159     if (num_mvs > s->num_mvs) {
00160         s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
00161         s->num_mvs = num_mvs;
00162     }
00163 
00164     if (num_blocks_packed > s->num_blocks_packed) {
00165         s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
00166         s->num_blocks_packed = num_blocks_packed;
00167     }
00168 
00169     /* read motion vectors */
00170     mvbits = (num_mvs*2*10+31) & ~31;
00171 
00172     if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
00173         return -1;
00174 
00175     init_get_bits(&gb, buf, mvbits);
00176     for (i=0; i<num_mvs; i++) {
00177         s->mv_codebook[i][0] = get_sbits(&gb, 10);
00178         s->mv_codebook[i][1] = get_sbits(&gb, 10);
00179     }
00180     buf += mvbits>>3;
00181 
00182     /* note ptr to uncompressed blocks */
00183     blocks_raw = buf;
00184     buf += num_blocks_raw*16;
00185 
00186     /* read compressed blocks */
00187     init_get_bits(&gb, buf, (buf_end-buf)<<3);
00188     for (i=0; i<num_blocks_packed; i++) {
00189         int tmp[4];
00190         for(j=0; j<4; j++)
00191             tmp[j] = get_bits(&gb, 8);
00192         for(j=0; j<16; j++)
00193             s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
00194     }
00195 
00196     if (get_bits_left(&gb) < vector_bits *
00197         (s->avctx->height/4) * (s->avctx->width/4))
00198         return -1;
00199 
00200     /* read vectors and build frame */
00201     for(y=0; y<s->avctx->height/4; y++)
00202     for(x=0; x<s->avctx->width/4; x++) {
00203         unsigned int vector = get_bits(&gb, vector_bits);
00204         const unsigned char *src;
00205         int src_stride;
00206 
00207         if (vector < num_mvs) {
00208             src = s->last_frame.data[0] +
00209                   (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
00210                    x*4 + s->mv_codebook[vector][0];
00211             src_stride = s->last_frame.linesize[0];
00212             if (src+3*src_stride+3>=frame0_end)
00213                 continue;
00214         }else{
00215             int offset = vector - num_mvs;
00216             if (offset<num_blocks_raw)
00217                 src = blocks_raw + 16*offset;
00218             else if (offset-num_blocks_raw<num_blocks_packed)
00219                 src = s->block_codebook[offset-num_blocks_raw];
00220             else
00221                 continue;
00222             src_stride = 4;
00223         }
00224 
00225         for(j=0; j<4; j++)
00226         for(i=0; i<4; i++)
00227             s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i)  ] =
00228                src[j*src_stride + i];
00229     }
00230 
00231     return 0;
00232 }
00233 
00235 static void cond_release_buffer(AVFrame *pic)
00236 {
00237     if (pic->data[0]) {
00238         av_freep(&pic->data[0]);
00239         av_free(pic->data[1]);
00240     }
00241 }
00242 
00243 static int tgv_decode_frame(AVCodecContext *avctx,
00244                             void *data, int *data_size,
00245                             AVPacket *avpkt)
00246 {
00247     const uint8_t *buf = avpkt->data;
00248     int buf_size = avpkt->size;
00249     TgvContext *s = avctx->priv_data;
00250     const uint8_t *buf_end = buf + buf_size;
00251     int chunk_type;
00252 
00253     chunk_type = AV_RL32(&buf[0]);
00254     buf += EA_PREAMBLE_SIZE;
00255 
00256     if (chunk_type==kVGT_TAG) {
00257         int pal_count, i;
00258         if(buf+12>buf_end) {
00259             av_log(avctx, AV_LOG_WARNING, "truncated header\n");
00260             return -1;
00261         }
00262 
00263         s->width  = AV_RL16(&buf[0]);
00264         s->height = AV_RL16(&buf[2]);
00265         if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
00266             avcodec_set_dimensions(s->avctx, s->width, s->height);
00267             cond_release_buffer(&s->frame);
00268             cond_release_buffer(&s->last_frame);
00269         }
00270 
00271         pal_count = AV_RL16(&buf[6]);
00272         buf += 12;
00273         for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
00274             s->palette[i] = AV_RB24(buf);
00275             buf += 3;
00276         }
00277     }
00278 
00279     if (av_image_check_size(s->width, s->height, 0, avctx))
00280         return -1;
00281 
00282     /* shuffle */
00283     FFSWAP(AVFrame, s->frame, s->last_frame);
00284     if (!s->frame.data[0]) {
00285         s->frame.reference = 1;
00286         s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
00287         s->frame.linesize[0] = s->width;
00288 
00289         /* allocate additional 12 bytes to accommodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
00290         s->frame.data[0] = av_malloc(s->width*s->height + 12);
00291         if (!s->frame.data[0])
00292             return AVERROR(ENOMEM);
00293         s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
00294         if (!s->frame.data[1]) {
00295             av_freep(&s->frame.data[0]);
00296             return AVERROR(ENOMEM);
00297         }
00298     }
00299     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
00300 
00301     if(chunk_type==kVGT_TAG) {
00302         s->frame.key_frame = 1;
00303         s->frame.pict_type = AV_PICTURE_TYPE_I;
00304         if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
00305             av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
00306             return -1;
00307         }
00308     }else{
00309         if (!s->last_frame.data[0]) {
00310             av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
00311             return buf_size;
00312         }
00313         s->frame.key_frame = 0;
00314         s->frame.pict_type = AV_PICTURE_TYPE_P;
00315         if (tgv_decode_inter(s, buf, buf_end)<0) {
00316             av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
00317             return -1;
00318         }
00319     }
00320 
00321     *data_size = sizeof(AVFrame);
00322     *(AVFrame*)data = s->frame;
00323 
00324     return buf_size;
00325 }
00326 
00327 static av_cold int tgv_decode_end(AVCodecContext *avctx)
00328 {
00329     TgvContext *s = avctx->priv_data;
00330     cond_release_buffer(&s->frame);
00331     cond_release_buffer(&s->last_frame);
00332     av_free(s->mv_codebook);
00333     av_free(s->block_codebook);
00334     return 0;
00335 }
00336 
00337 AVCodec ff_eatgv_decoder = {
00338     .name           = "eatgv",
00339     .type           = AVMEDIA_TYPE_VIDEO,
00340     .id             = CODEC_ID_TGV,
00341     .priv_data_size = sizeof(TgvContext),
00342     .init           = tgv_decode_init,
00343     .close          = tgv_decode_end,
00344     .decode         = tgv_decode_frame,
00345     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
00346 };