FFmpeg: libavcodec/eamad.c Source File

00001 /*
00002  * Electronic Arts Madcow Video Decoder
00003  * Copyright (c) 2007-2009 Peter Ross
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "get_bits.h"
00033 #include "dsputil.h"
00034 #include "aandcttab.h"
00035 #include "eaidct.h"
00036 #include "mpeg12.h"
00037 #include "mpeg12data.h"
00038 #include "libavutil/imgutils.h"
00039 
00040 #define EA_PREAMBLE_SIZE    8
00041 #define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
00042 #define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
00043 #define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
00044 
00045 typedef struct MadContext {
00046     AVCodecContext *avctx;
00047     DSPContext dsp;
00048     AVFrame frame;
00049     AVFrame last_frame;
00050     GetBitContext gb;
00051     void *bitstream_buf;
00052     unsigned int bitstream_buf_size;
00053     DECLARE_ALIGNED(16, DCTELEM, block)[64];
00054     ScanTable scantable;
00055     uint16_t quant_matrix[64];
00056     int mb_x;
00057     int mb_y;
00058 } MadContext;
00059 
00060 static av_cold int decode_init(AVCodecContext *avctx)
00061 {
00062     MadContext *s = avctx->priv_data;
00063     s->avctx = avctx;
00064     avctx->pix_fmt = PIX_FMT_YUV420P;
00065     ff_dsputil_init(&s->dsp, avctx);
00066     ff_init_scantable_permutation(s->dsp.idct_permutation, FF_NO_IDCT_PERM);
00067     ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
00068     ff_mpeg12_init_vlcs();
00069     return 0;
00070 }
00071 
00072 static inline void comp(unsigned char *dst, int dst_stride,
00073                         unsigned char *src, int src_stride, int add)
00074 {
00075     int j, i;
00076     for (j=0; j<8; j++)
00077         for (i=0; i<8; i++)
00078             dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
00079 }
00080 
00081 static inline void comp_block(MadContext *t, int mb_x, int mb_y,
00082                               int j, int mv_x, int mv_y, int add)
00083 {
00084     if (j < 4) {
00085         unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;
00086         if (offset >= (t->avctx->height - 7) * t->last_frame.linesize[0] - 7)
00087             return;
00088         comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
00089              t->frame.linesize[0],
00090              t->last_frame.data[0] + offset,
00091              t->last_frame.linesize[0], add);
00092     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
00093         int index = j - 3;
00094         unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2);
00095         if (offset >= (t->avctx->height/2 - 7) * t->last_frame.linesize[index] - 7)
00096             return;
00097         comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
00098              t->frame.linesize[index],
00099              t->last_frame.data[index] + offset,
00100              t->last_frame.linesize[index], add);
00101     }
00102 }
00103 
00104 static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
00105 {
00106     if (j < 4) {
00107         ff_ea_idct_put_c(
00108             t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
00109             t->frame.linesize[0], block);
00110     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
00111         int index = j - 3;
00112         ff_ea_idct_put_c(
00113             t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
00114             t->frame.linesize[index], block);
00115     }
00116 }
00117 
00118 static inline int decode_block_intra(MadContext *s, DCTELEM * block)
00119 {
00120     int level, i, j, run;
00121     RLTable *rl = &ff_rl_mpeg1;
00122     const uint8_t *scantable = s->scantable.permutated;
00123     int16_t *quant_matrix = s->quant_matrix;
00124 
00125     block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
00126 
00127     /* The RL decoder is derived from mpeg1_decode_block_intra;
00128        Escaped level and run values a decoded differently */
00129     i = 0;
00130     {
00131         OPEN_READER(re, &s->gb);
00132         /* now quantify & encode AC coefficients */
00133         for (;;) {
00134             UPDATE_CACHE(re, &s->gb);
00135             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
00136 
00137             if (level == 127) {
00138                 break;
00139             } else if (level != 0) {
00140                 i += run;
00141                 j = scantable[i];
00142                 level = (level*quant_matrix[j]) >> 4;
00143                 level = (level-1)|1;
00144                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
00145                 LAST_SKIP_BITS(re, &s->gb, 1);
00146             } else {
00147                 /* escape */
00148                 UPDATE_CACHE(re, &s->gb);
00149                 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
00150 
00151                 UPDATE_CACHE(re, &s->gb);
00152                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
00153 
00154                 i += run;
00155                 j = scantable[i];
00156                 if (level < 0) {
00157                     level = -level;
00158                     level = (level*quant_matrix[j]) >> 4;
00159                     level = (level-1)|1;
00160                     level = -level;
00161                 } else {
00162                     level = (level*quant_matrix[j]) >> 4;
00163                     level = (level-1)|1;
00164                 }
00165             }
00166             if (i > 63) {
00167                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
00168                 return -1;
00169             }
00170 
00171             block[j] = level;
00172         }
00173         CLOSE_READER(re, &s->gb);
00174     }
00175     return 0;
00176 }
00177 
00178 static int decode_motion(GetBitContext *gb)
00179 {
00180     int value = 0;
00181     if (get_bits1(gb)) {
00182         if (get_bits1(gb))
00183             value = -17;
00184         value += get_bits(gb, 4) + 1;
00185     }
00186     return value;
00187 }
00188 
00189 static int decode_mb(MadContext *s, int inter)
00190 {
00191     int mv_map = 0;
00192     int mv_x, mv_y;
00193     int j;
00194 
00195     if (inter) {
00196         int v = decode210(&s->gb);
00197         if (v < 2) {
00198             mv_map = v ? get_bits(&s->gb, 6) : 63;
00199             mv_x = decode_motion(&s->gb);
00200             mv_y = decode_motion(&s->gb);
00201         }
00202     }
00203 
00204     for (j=0; j<6; j++) {
00205         if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map
00206             int add = 2*decode_motion(&s->gb);
00207             if (s->last_frame.data[0])
00208                 comp_block(s, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
00209         } else {
00210             s->dsp.clear_block(s->block);
00211             if(decode_block_intra(s, s->block) < 0)
00212                 return -1;
00213             idct_put(s, s->block, s->mb_x, s->mb_y, j);
00214         }
00215     }
00216     return 0;
00217 }
00218 
00219 static void calc_quant_matrix(MadContext *s, int qscale)
00220 {
00221     int i;
00222 
00223     s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
00224     for (i=1; i<64; i++)
00225         s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
00226 }
00227 
00228 static int decode_frame(AVCodecContext *avctx,
00229                         void *data, int *data_size,
00230                         AVPacket *avpkt)
00231 {
00232     const uint8_t *buf = avpkt->data;
00233     int buf_size       = avpkt->size;
00234     const uint8_t *buf_end = buf+buf_size;
00235     MadContext *s     = avctx->priv_data;
00236     int width, height;
00237     int chunk_type;
00238     int inter;
00239 
00240     if (buf_size < 17) {
00241         av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
00242         *data_size = 0;
00243         return -1;
00244     }
00245 
00246     chunk_type = AV_RL32(&buf[0]);
00247     inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
00248     buf += 8;
00249 
00250     av_reduce(&avctx->time_base.num, &avctx->time_base.den,
00251               AV_RL16(&buf[6]), 1000, 1<<30);
00252 
00253     width  = AV_RL16(&buf[8]);
00254     height = AV_RL16(&buf[10]);
00255     calc_quant_matrix(s, buf[13]);
00256     buf += 16;
00257 
00258     if (avctx->width != width || avctx->height != height) {
00259         if((width * height)/2048*7 > buf_end-buf)
00260             return -1;
00261         if (av_image_check_size(width, height, 0, avctx) < 0)
00262             return -1;
00263         avcodec_set_dimensions(avctx, width, height);
00264         if (s->frame.data[0])
00265             avctx->release_buffer(avctx, &s->frame);
00266         if (s->last_frame.data[0])
00267             avctx->release_buffer(avctx, &s->last_frame);
00268     }
00269 
00270     s->frame.reference = 3;
00271     if (!s->frame.data[0]) {
00272         if (avctx->get_buffer(avctx, &s->frame) < 0) {
00273             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00274             return -1;
00275         }
00276     }
00277 
00278     av_fast_malloc(&s->bitstream_buf, &s->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE);
00279     if (!s->bitstream_buf)
00280         return AVERROR(ENOMEM);
00281     s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
00282     memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
00283     init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
00284 
00285     for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
00286         for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
00287             if(decode_mb(s, inter) < 0)
00288                 return -1;
00289 
00290     *data_size = sizeof(AVFrame);
00291     *(AVFrame*)data = s->frame;
00292 
00293     if (chunk_type != MADe_TAG)
00294         FFSWAP(AVFrame, s->frame, s->last_frame);
00295 
00296     return buf_size;
00297 }
00298 
00299 static av_cold int decode_end(AVCodecContext *avctx)
00300 {
00301     MadContext *t = avctx->priv_data;
00302     if (t->frame.data[0])
00303         avctx->release_buffer(avctx, &t->frame);
00304     if (t->last_frame.data[0])
00305         avctx->release_buffer(avctx, &t->last_frame);
00306     av_free(t->bitstream_buf);
00307     return 0;
00308 }
00309 
00310 AVCodec ff_eamad_decoder = {
00311     .name           = "eamad",
00312     .type           = AVMEDIA_TYPE_VIDEO,
00313     .id             = AV_CODEC_ID_MAD,
00314     .priv_data_size = sizeof(MadContext),
00315     .init           = decode_init,
00316     .close          = decode_end,
00317     .decode         = decode_frame,
00318     .capabilities   = CODEC_CAP_DR1,
00319     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
00320 };