libavcodec/mdec.c

   1 /*
   2  * Sony PlayStation MDEC (Motion DECoder)
   3  * Copyright (c) 2003 Michael Niedermayer
   4  *
   5  * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /**
  25  * @file libavcodec/mdec.c
  26  * Sony PlayStation MDEC (Motion DECoder)
  27  * This is very similar to intra-only MPEG-1.
  28  */
  29
  30 #include "avcodec.h"
  31 #include "dsputil.h"
  32 #include "mpegvideo.h"
  33 #include "mpeg12.h"
  34
  35 typedef struct MDECContext{
  36     AVCodecContext *avctx;
  37     DSPContext dsp;
  38     AVFrame picture;
  39     GetBitContext gb;
  40     ScanTable scantable;
  41     int version;
  42     int qscale;
  43     int last_dc[3];
  44     int mb_width;
  45     int mb_height;
  46     int mb_x, mb_y;
  47     DECLARE_ALIGNED_16(DCTELEM, block[6][64]);
  48     uint8_t *bitstream_buffer;
  49     unsigned int bitstream_buffer_size;
  50     int block_last_index[6];
  51 } MDECContext;
  52
  53 //very similar to MPEG-1
  54 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
  55 {
  56     int level, diff, i, j, run;
  57     int component;
  58     RLTable *rl = &ff_rl_mpeg1;
  59     uint8_t * const scantable= a->scantable.permutated;
  60     const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
  61     const int qscale= a->qscale;
  62
  63     /* DC coefficient */
  64     if(a->version==2){
  65         block[0]= 2*get_sbits(&a->gb, 10) + 1024;
  66     }else{
  67         component = (n <= 3 ? 0 : n - 4 + 1);
  68         diff = decode_dc(&a->gb, component);
  69         if (diff >= 0xffff)
  70             return -1;
  71         a->last_dc[component]+= diff;
  72         block[0] = a->last_dc[component]<<3;
  73     }
  74
  75     i = 0;
  76     {
  77         OPEN_READER(re, &a->gb);
  78         /* now quantify & encode AC coefficients */
  79         for(;;) {
  80             UPDATE_CACHE(re, &a->gb);
  81             GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
  82
  83             if(level == 127){
  84                 break;
  85             } else if(level != 0) {
  86                 i += run;
  87                 j = scantable[i];
  88                 level= (level*qscale*quant_matrix[j])>>3;
  89                 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
  90                 LAST_SKIP_BITS(re, &a->gb, 1);
  91             } else {
  92                 /* escape */
  93                 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
  94                 UPDATE_CACHE(re, &a->gb);
  95                 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
  96                 i += run;
  97                 j = scantable[i];
  98                 if(level<0){
  99                     level= -level;
 100                     level= (level*qscale*quant_matrix[j])>>3;
 101                     level= (level-1)|1;
 102                     level= -level;
 103                 }else{
 104                     level= (level*qscale*quant_matrix[j])>>3;
 105                     level= (level-1)|1;
 106                 }
 107             }
 108             if (i > 63){
 109                 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
 110                 return -1;
 111             }
 112
 113             block[j] = level;
 114         }
 115         CLOSE_READER(re, &a->gb);
 116     }
 117     a->block_last_index[n] = i;
 118     return 0;
 119 }
 120
 121 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
 122     int i;
 123     const int block_index[6]= {5,4,0,1,2,3};
 124
 125     a->dsp.clear_blocks(block[0]);
 126
 127     for(i=0; i<6; i++){
 128         if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
 129             return -1;
 130     }
 131     return 0;
 132 }
 133
 134 static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
 135     DCTELEM (*block)[64]= a->block;
 136     int linesize= a->picture.linesize[0];
 137
 138     uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
 139     uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
 140     uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
 141
 142     a->dsp.idct_put(dest_y                 , linesize, block[0]);
 143     a->dsp.idct_put(dest_y              + 8, linesize, block[1]);
 144     a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
 145     a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
 146
 147     if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
 148         a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
 149         a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
 150     }
 151 }
 152
 153 static int decode_frame(AVCodecContext *avctx,
 154                         void *data, int *data_size,
 155                         AVPacket *avpkt)
 156 {
 157     const uint8_t *buf = avpkt->data;
 158     int buf_size = avpkt->size;
 159     MDECContext * const a = avctx->priv_data;
 160     AVFrame *picture = data;
 161     AVFrame * const p= &a->picture;
 162     int i;
 163
 164     if(p->data[0])
 165         avctx->release_buffer(avctx, p);
 166
 167     p->reference= 0;
 168     if(avctx->get_buffer(avctx, p) < 0){
 169         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 170         return -1;
 171     }
 172     p->pict_type= FF_I_TYPE;
 173     p->key_frame= 1;
 174
 175     av_fast_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 176     if (!a->bitstream_buffer)
 177         return AVERROR(ENOMEM);
 178     for(i=0; i<buf_size; i+=2){
 179         a->bitstream_buffer[i]  = buf[i+1];
 180         a->bitstream_buffer[i+1]= buf[i  ];
 181     }
 182     init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
 183
 184     /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
 185     skip_bits(&a->gb, 32);
 186
 187     a->qscale=  get_bits(&a->gb, 16);
 188     a->version= get_bits(&a->gb, 16);
 189
 190     a->last_dc[0]=
 191     a->last_dc[1]=
 192     a->last_dc[2]= 128;
 193
 194     for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
 195         for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
 196             if( decode_mb(a, a->block) <0)
 197                 return -1;
 198
 199             idct_put(a, a->mb_x, a->mb_y);
 200         }
 201     }
 202
 203     p->quality= a->qscale * FF_QP2LAMBDA;
 204     memset(p->qscale_table, a->qscale, p->qstride*a->mb_height);
 205
 206     *picture   = a->picture;
 207     *data_size = sizeof(AVPicture);
 208
 209     return (get_bits_count(&a->gb)+31)/32*4;
 210 }
 211
 212 static av_cold void mdec_common_init(AVCodecContext *avctx){
 213     MDECContext * const a = avctx->priv_data;
 214
 215     dsputil_init(&a->dsp, avctx);
 216
 217     a->mb_width   = (avctx->coded_width  + 15) / 16;
 218     a->mb_height  = (avctx->coded_height + 15) / 16;
 219
 220     avctx->coded_frame= &a->picture;
 221     a->avctx= avctx;
 222 }
 223
 224 static av_cold int decode_init(AVCodecContext *avctx){
 225     MDECContext * const a = avctx->priv_data;
 226     AVFrame *p= &a->picture;
 227
 228     mdec_common_init(avctx);
 229     ff_mpeg12_init_vlcs();
 230     ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
 231
 232     p->qstride= a->mb_width;
 233     p->qscale_table= av_mallocz( p->qstride * a->mb_height);
 234     avctx->pix_fmt= PIX_FMT_YUV420P;
 235
 236     return 0;
 237 }
 238
 239 static av_cold int decode_end(AVCodecContext *avctx){
 240     MDECContext * const a = avctx->priv_data;
 241
 242     av_freep(&a->bitstream_buffer);
 243     av_freep(&a->picture.qscale_table);
 244     a->bitstream_buffer_size=0;
 245
 246     return 0;
 247 }
 248
 249 AVCodec mdec_decoder = {
 250     "mdec",
 251     CODEC_TYPE_VIDEO,
 252     CODEC_ID_MDEC,
 253     sizeof(MDECContext),
 254     decode_init,
 255     NULL,
 256     decode_end,
 257     decode_frame,
 258     CODEC_CAP_DR1,
 259     .long_name= NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
 260 };
 261