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libavcodec/mdec.c

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00001 /*
00002  * Sony PlayStation MDEC (Motion DECoder)
00003  * Copyright (c) 2003 Michael Niedermayer
00004  *
00005  * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with FFmpeg; if not, write to the Free Software
00021  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00022  */
00023 
00030 #include "avcodec.h"
00031 #include "dsputil.h"
00032 #include "mpegvideo.h"
00033 #include "mpeg12.h"
00034 
00035 typedef struct MDECContext{
00036     AVCodecContext *avctx;
00037     DSPContext dsp;
00038     AVFrame picture;
00039     GetBitContext gb;
00040     ScanTable scantable;
00041     int version;
00042     int qscale;
00043     int last_dc[3];
00044     int mb_width;
00045     int mb_height;
00046     int mb_x, mb_y;
00047     DECLARE_ALIGNED_16(DCTELEM, block[6][64]);
00048     DECLARE_ALIGNED_8(uint16_t, intra_matrix[64]);
00049     DECLARE_ALIGNED_8(int, q_intra_matrix[64]);
00050     uint8_t *bitstream_buffer;
00051     unsigned int bitstream_buffer_size;
00052     int block_last_index[6];
00053 } MDECContext;
00054 
00055 //very similar to MPEG-1
00056 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
00057 {
00058     int level, diff, i, j, run;
00059     int component;
00060     RLTable *rl = &ff_rl_mpeg1;
00061     uint8_t * const scantable= a->scantable.permutated;
00062     const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
00063     const int qscale= a->qscale;
00064 
00065     /* DC coefficient */
00066     if(a->version==2){
00067         block[0]= 2*get_sbits(&a->gb, 10) + 1024;
00068     }else{
00069         component = (n <= 3 ? 0 : n - 4 + 1);
00070         diff = decode_dc(&a->gb, component);
00071         if (diff >= 0xffff)
00072             return -1;
00073         a->last_dc[component]+= diff;
00074         block[0] = a->last_dc[component]<<3;
00075     }
00076 
00077     i = 0;
00078     {
00079         OPEN_READER(re, &a->gb);
00080         /* now quantify & encode AC coefficients */
00081         for(;;) {
00082             UPDATE_CACHE(re, &a->gb);
00083             GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
00084 
00085             if(level == 127){
00086                 break;
00087             } else if(level != 0) {
00088                 i += run;
00089                 j = scantable[i];
00090                 level= (level*qscale*quant_matrix[j])>>3;
00091                 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
00092                 LAST_SKIP_BITS(re, &a->gb, 1);
00093             } else {
00094                 /* escape */
00095                 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
00096                 UPDATE_CACHE(re, &a->gb);
00097                 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
00098                 i += run;
00099                 j = scantable[i];
00100                 if(level<0){
00101                     level= -level;
00102                     level= (level*qscale*quant_matrix[j])>>3;
00103                     level= (level-1)|1;
00104                     level= -level;
00105                 }else{
00106                     level= (level*qscale*quant_matrix[j])>>3;
00107                     level= (level-1)|1;
00108                 }
00109             }
00110             if (i > 63){
00111                 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
00112                 return -1;
00113             }
00114 
00115             block[j] = level;
00116         }
00117         CLOSE_READER(re, &a->gb);
00118     }
00119     a->block_last_index[n] = i;
00120     return 0;
00121 }
00122 
00123 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
00124     int i;
00125     const int block_index[6]= {5,4,0,1,2,3};
00126 
00127     a->dsp.clear_blocks(block[0]);
00128 
00129     for(i=0; i<6; i++){
00130         if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
00131             return -1;
00132     }
00133     return 0;
00134 }
00135 
00136 static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
00137     DCTELEM (*block)[64]= a->block;
00138     int linesize= a->picture.linesize[0];
00139 
00140     uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
00141     uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
00142     uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
00143 
00144     a->dsp.idct_put(dest_y                 , linesize, block[0]);
00145     a->dsp.idct_put(dest_y              + 8, linesize, block[1]);
00146     a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
00147     a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
00148 
00149     if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
00150         a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
00151         a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
00152     }
00153 }
00154 
00155 static int decode_frame(AVCodecContext *avctx,
00156                         void *data, int *data_size,
00157                         const uint8_t *buf, int buf_size)
00158 {
00159     MDECContext * const a = avctx->priv_data;
00160     AVFrame *picture = data;
00161     AVFrame * const p= &a->picture;
00162     int i;
00163 
00164     if(p->data[0])
00165         avctx->release_buffer(avctx, p);
00166 
00167     p->reference= 0;
00168     if(avctx->get_buffer(avctx, p) < 0){
00169         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00170         return -1;
00171     }
00172     p->pict_type= FF_I_TYPE;
00173     p->key_frame= 1;
00174 
00175     a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00176     for(i=0; i<buf_size; i+=2){
00177         a->bitstream_buffer[i]  = buf[i+1];
00178         a->bitstream_buffer[i+1]= buf[i  ];
00179     }
00180     init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
00181 
00182     /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
00183     skip_bits(&a->gb, 32);
00184 
00185     a->qscale=  get_bits(&a->gb, 16);
00186     a->version= get_bits(&a->gb, 16);
00187 
00188     a->last_dc[0]=
00189     a->last_dc[1]=
00190     a->last_dc[2]= 128;
00191 
00192     for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
00193         for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
00194             if( decode_mb(a, a->block) <0)
00195                 return -1;
00196 
00197             idct_put(a, a->mb_x, a->mb_y);
00198         }
00199     }
00200 
00201     p->quality= a->qscale * FF_QP2LAMBDA;
00202     memset(p->qscale_table, a->qscale, p->qstride*a->mb_height);
00203 
00204     *picture   = a->picture;
00205     *data_size = sizeof(AVPicture);
00206 
00207     return (get_bits_count(&a->gb)+31)/32*4;
00208 }
00209 
00210 static av_cold void mdec_common_init(AVCodecContext *avctx){
00211     MDECContext * const a = avctx->priv_data;
00212 
00213     dsputil_init(&a->dsp, avctx);
00214 
00215     a->mb_width   = (avctx->coded_width  + 15) / 16;
00216     a->mb_height  = (avctx->coded_height + 15) / 16;
00217 
00218     avctx->coded_frame= &a->picture;
00219     a->avctx= avctx;
00220 }
00221 
00222 static av_cold int decode_init(AVCodecContext *avctx){
00223     MDECContext * const a = avctx->priv_data;
00224     AVFrame *p= &a->picture;
00225 
00226     mdec_common_init(avctx);
00227     ff_mpeg12_init_vlcs();
00228     ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
00229 
00230     p->qstride= a->mb_width;
00231     p->qscale_table= av_mallocz( p->qstride * a->mb_height);
00232     avctx->pix_fmt= PIX_FMT_YUV420P;
00233 
00234     return 0;
00235 }
00236 
00237 static av_cold int decode_end(AVCodecContext *avctx){
00238     MDECContext * const a = avctx->priv_data;
00239 
00240     av_freep(&a->bitstream_buffer);
00241     av_freep(&a->picture.qscale_table);
00242     a->bitstream_buffer_size=0;
00243 
00244     return 0;
00245 }
00246 
00247 AVCodec mdec_decoder = {
00248     "mdec",
00249     CODEC_TYPE_VIDEO,
00250     CODEC_ID_MDEC,
00251     sizeof(MDECContext),
00252     decode_init,
00253     NULL,
00254     decode_end,
00255     decode_frame,
00256     CODEC_CAP_DR1,
00257     .long_name= NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
00258 };
00259 

Generated on Tue Nov 4 2014 12:59:22 for ffmpeg by  doxygen 1.7.1