libavcodec/eamad.c

   1 /*
   2  * Electronic Arts Madcow Video Decoder
   3  * Copyright (c) 2007-2009 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/eamad.c
  24  * Electronic Arts Madcow Video Decoder
  25  * by Peter Ross <pross@xvid.org>
  26  *
  27  * Technical details here:
  28  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD
  29  */
  30
  31 #include "avcodec.h"
  32 #include "get_bits.h"
  33 #include "dsputil.h"
  34 #include "aandcttab.h"
  35 #include "mpeg12.h"
  36 #include "mpeg12data.h"
  37
  38 #define EA_PREAMBLE_SIZE    8
  39 #define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
  40 #define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
  41 #define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
  42
  43 typedef struct MadContext {
  44     MpegEncContext s;
  45     AVFrame frame;
  46     AVFrame last_frame;
  47     void *bitstream_buf;
  48     unsigned int bitstream_buf_size;
  49     DECLARE_ALIGNED_16(DCTELEM, block[64]);
  50 } MadContext;
  51
  52 static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count)
  53 {
  54     int i;
  55     for (i=0; i<count; i++)
  56         dst[i] = bswap_16(src[i]);
  57 }
  58
  59 static av_cold int decode_init(AVCodecContext *avctx)
  60 {
  61     MadContext *t = avctx->priv_data;
  62     MpegEncContext *s = &t->s;
  63     s->avctx = avctx;
  64     avctx->pix_fmt = PIX_FMT_YUV420P;
  65     if (avctx->idct_algo == FF_IDCT_AUTO)
  66         avctx->idct_algo = FF_IDCT_EA;
  67     dsputil_init(&s->dsp, avctx);
  68     ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);
  69     ff_mpeg12_init_vlcs();
  70     return 0;
  71 }
  72
  73 static inline void comp(unsigned char *dst, int dst_stride,
  74                         unsigned char *src, int src_stride, int add)
  75 {
  76     int j, i;
  77     for (j=0; j<8; j++)
  78         for (i=0; i<8; i++)
  79             dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
  80 }
  81
  82 static inline void comp_block(MadContext *t, int mb_x, int mb_y,
  83                               int j, int mv_x, int mv_y, int add)
  84 {
  85     MpegEncContext *s = &t->s;
  86     if (j < 4) {
  87         comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
  88              t->frame.linesize[0],
  89              t->last_frame.data[0] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x,
  90              t->last_frame.linesize[0], add);
  91     } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
  92         int index = j - 3;
  93         comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
  94              t->frame.linesize[index],
  95              t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2),
  96              t->last_frame.linesize[index], add);
  97     }
  98 }
  99
 100 static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
 101 {
 102     MpegEncContext *s = &t->s;
 103     if (j < 4) {
 104         s->dsp.idct_put(
 105             t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
 106             t->frame.linesize[0], block);
 107     } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
 108         int index = j - 3;
 109         s->dsp.idct_put(
 110             t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
 111             t->frame.linesize[index], block);
 112     }
 113 }
 114
 115 static inline void decode_block_intra(MadContext * t, DCTELEM * block)
 116 {
 117     MpegEncContext *s = &t->s;
 118     int level, i, j, run;
 119     RLTable *rl = &ff_rl_mpeg1;
 120     const uint8_t *scantable = s->intra_scantable.permutated;
 121     int16_t *quant_matrix = s->intra_matrix;
 122
 123     block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
 124
 125     /* The RL decoder is derived from mpeg1_decode_block_intra;
 126        Escaped level and run values a decoded differently */
 127     i = 0;
 128     {
 129         OPEN_READER(re, &s->gb);
 130         /* now quantify & encode AC coefficients */
 131         for (;;) {
 132             UPDATE_CACHE(re, &s->gb);
 133             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 134
 135             if (level == 127) {
 136                 break;
 137             } else if (level != 0) {
 138                 i += run;
 139                 j = scantable[i];
 140                 level = (level*quant_matrix[j]) >> 4;
 141                 level = (level-1)|1;
 142                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
 143                 LAST_SKIP_BITS(re, &s->gb, 1);
 144             } else {
 145                 /* escape */
 146                 UPDATE_CACHE(re, &s->gb);
 147                 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
 148
 149                 UPDATE_CACHE(re, &s->gb);
 150                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
 151
 152                 i += run;
 153                 j = scantable[i];
 154                 if (level < 0) {
 155                     level = -level;
 156                     level = (level*quant_matrix[j]) >> 4;
 157                     level = (level-1)|1;
 158                     level = -level;
 159                 } else {
 160                     level = (level*quant_matrix[j]) >> 4;
 161                     level = (level-1)|1;
 162                 }
 163             }
 164             if (i > 63) {
 165                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
 166                 return;
 167             }
 168
 169             block[j] = level;
 170         }
 171         CLOSE_READER(re, &s->gb);
 172     }
 173 }
 174
 175 static int decode_motion(GetBitContext *gb)
 176 {
 177     int value = 0;
 178     if (get_bits1(gb)) {
 179         if (get_bits1(gb))
 180             value = -17;
 181         value += get_bits(gb, 4) + 1;
 182     }
 183     return value;
 184 }
 185
 186 static void decode_mb(MadContext *t, int inter)
 187 {
 188     MpegEncContext *s = &t->s;
 189     int mv_map = 0;
 190     int mv_x, mv_y;
 191     int j;
 192
 193     if (inter) {
 194         int v = decode210(&s->gb);
 195         if (v < 2) {
 196             mv_map = v ? get_bits(&s->gb, 6) : 63;
 197             mv_x = decode_motion(&s->gb);
 198             mv_y = decode_motion(&s->gb);
 199         } else {
 200             mv_map = 0;
 201         }
 202     }
 203
 204     for (j=0; j<6; j++) {
 205         if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map
 206             int add = 2*decode_motion(&s->gb);
 207             comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
 208         } else {
 209             s->dsp.clear_block(t->block);
 210             decode_block_intra(t, t->block);
 211             idct_put(t, t->block, s->mb_x, s->mb_y, j);
 212         }
 213     }
 214 }
 215
 216 static void calc_intra_matrix(MadContext *t, int qscale)
 217 {
 218     MpegEncContext *s = &t->s;
 219     int i;
 220
 221     if (s->avctx->idct_algo == FF_IDCT_EA) {
 222         s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
 223         for (i=1; i<64; i++)
 224             s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
 225     } else {
 226         s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0];
 227         for (i=1; i<64; i++)
 228             s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1;
 229     }
 230 }
 231
 232 static int decode_frame(AVCodecContext *avctx,
 233                         void *data, int *data_size,
 234                         AVPacket *avpkt)
 235 {
 236     const uint8_t *buf = avpkt->data;
 237     int buf_size       = avpkt->size;
 238     const uint8_t *buf_end = buf+buf_size;
 239     MadContext *t     = avctx->priv_data;
 240     MpegEncContext *s = &t->s;
 241     int chunk_type;
 242     int inter;
 243
 244     if (buf_size < 17) {
 245         av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
 246         *data_size = 0;
 247         return -1;
 248     }
 249
 250     chunk_type = AV_RL32(&buf[0]);
 251     inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
 252     buf += 8;
 253
 254     av_reduce(&avctx->time_base.num, &avctx->time_base.den,
 255               AV_RL16(&buf[6]), 1000, 1<<30);
 256
 257     s->width  = AV_RL16(&buf[8]);
 258     s->height = AV_RL16(&buf[10]);
 259     calc_intra_matrix(t, buf[13]);
 260     buf += 16;
 261
 262     if (avctx->width != s->width || avctx->height != s->height) {
 263         if (avcodec_check_dimensions(avctx, s->width, s->height) < 0)
 264             return -1;
 265         avcodec_set_dimensions(avctx, s->width, s->height);
 266         if (t->frame.data[0])
 267             avctx->release_buffer(avctx, &t->frame);
 268     }
 269
 270     t->frame.reference = 1;
 271     if (!t->frame.data[0]) {
 272         if (avctx->get_buffer(avctx, &t->frame) < 0) {
 273             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 274             return -1;
 275         }
 276     }
 277
 278     av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE);
 279     if (!t->bitstream_buf)
 280         return AVERROR(ENOMEM);
 281     bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
 282     init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf));
 283
 284     for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
 285         for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
 286             decode_mb(t, inter);
 287
 288     *data_size = sizeof(AVFrame);
 289     *(AVFrame*)data = t->frame;
 290
 291     if (chunk_type != MADe_TAG)
 292         FFSWAP(AVFrame, t->frame, t->last_frame);
 293
 294     return buf_size;
 295 }
 296
 297 static av_cold int decode_end(AVCodecContext *avctx)
 298 {
 299     MadContext *t = avctx->priv_data;
 300     if (t->frame.data[0])
 301         avctx->release_buffer(avctx, &t->frame);
 302     if (t->last_frame.data[0])
 303         avctx->release_buffer(avctx, &t->last_frame);
 304     av_free(t->bitstream_buf);
 305     return 0;
 306 }
 307
 308 AVCodec eamad_decoder = {
 309     "eamad",
 310     CODEC_TYPE_VIDEO,
 311     CODEC_ID_MAD,
 312     sizeof(MadContext),
 313     decode_init,
 314     NULL,
 315     decode_end,
 316     decode_frame,
 317     CODEC_CAP_DR1,
 318     .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
 319 };