FFmpeg: libavcodec/mdec.c Source File

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 #include "thread.h"
00035 
00036 typedef struct MDECContext{
00037     AVCodecContext *avctx;
00038     DSPContext dsp;
00039     AVFrame picture;
00040     GetBitContext gb;
00041     ScanTable scantable;
00042     int version;
00043     int qscale;
00044     int last_dc[3];
00045     int mb_width;
00046     int mb_height;
00047     int mb_x, mb_y;
00048     DECLARE_ALIGNED(16, DCTELEM, block)[6][64];
00049     uint8_t *bitstream_buffer;
00050     unsigned int bitstream_buffer_size;
00051     int block_last_index[6];
00052 } MDECContext;
00053 
00054 //very similar to MPEG-1
00055 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
00056 {
00057     int level, diff, i, j, run;
00058     int component;
00059     RLTable *rl = &ff_rl_mpeg1;
00060     uint8_t * const scantable= a->scantable.permutated;
00061     const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
00062     const int qscale= a->qscale;
00063 
00064     /* DC coefficient */
00065     if(a->version==2){
00066         block[0]= 2*get_sbits(&a->gb, 10) + 1024;
00067     }else{
00068         component = (n <= 3 ? 0 : n - 4 + 1);
00069         diff = decode_dc(&a->gb, component);
00070         if (diff >= 0xffff)
00071             return -1;
00072         a->last_dc[component]+= diff;
00073         block[0] = a->last_dc[component]<<3;
00074     }
00075 
00076     i = 0;
00077     {
00078         OPEN_READER(re, &a->gb);
00079         /* now quantify & encode AC coefficients */
00080         for(;;) {
00081             UPDATE_CACHE(re, &a->gb);
00082             GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
00083 
00084             if(level == 127){
00085                 break;
00086             } else if(level != 0) {
00087                 i += run;
00088                 j = scantable[i];
00089                 level= (level*qscale*quant_matrix[j])>>3;
00090                 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
00091                 LAST_SKIP_BITS(re, &a->gb, 1);
00092             } else {
00093                 /* escape */
00094                 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
00095                 UPDATE_CACHE(re, &a->gb);
00096                 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
00097                 i += run;
00098                 j = scantable[i];
00099                 if(level<0){
00100                     level= -level;
00101                     level= (level*qscale*quant_matrix[j])>>3;
00102                     level= (level-1)|1;
00103                     level= -level;
00104                 }else{
00105                     level= (level*qscale*quant_matrix[j])>>3;
00106                     level= (level-1)|1;
00107                 }
00108             }
00109             if (i > 63){
00110                 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
00111                 return -1;
00112             }
00113 
00114             block[j] = level;
00115         }
00116         CLOSE_READER(re, &a->gb);
00117     }
00118     a->block_last_index[n] = i;
00119     return 0;
00120 }
00121 
00122 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
00123     int i;
00124     const int block_index[6]= {5,4,0,1,2,3};
00125 
00126     a->dsp.clear_blocks(block[0]);
00127 
00128     for(i=0; i<6; i++){
00129         if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0 ||
00130             get_bits_left(&a->gb) < 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                         AVPacket *avpkt)
00158 {
00159     const uint8_t *buf = avpkt->data;
00160     int buf_size = avpkt->size;
00161     MDECContext * const a = avctx->priv_data;
00162     AVFrame *picture = data;
00163     AVFrame * const p= &a->picture;
00164     int i;
00165 
00166     if(p->data[0])
00167         ff_thread_release_buffer(avctx, p);
00168 
00169     p->reference= 0;
00170     if(ff_thread_get_buffer(avctx, p) < 0){
00171         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00172         return -1;
00173     }
00174     p->pict_type= AV_PICTURE_TYPE_I;
00175     p->key_frame= 1;
00176 
00177     av_fast_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
00178     if (!a->bitstream_buffer)
00179         return AVERROR(ENOMEM);
00180     for(i=0; i<buf_size; i+=2){
00181         a->bitstream_buffer[i]  = buf[i+1];
00182         a->bitstream_buffer[i+1]= buf[i  ];
00183     }
00184     init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
00185 
00186     /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
00187     skip_bits(&a->gb, 32);
00188 
00189     a->qscale=  get_bits(&a->gb, 16);
00190     a->version= get_bits(&a->gb, 16);
00191 
00192     a->last_dc[0]=
00193     a->last_dc[1]=
00194     a->last_dc[2]= 128;
00195 
00196     for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
00197         for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
00198             if( decode_mb(a, a->block) <0)
00199                 return -1;
00200 
00201             idct_put(a, a->mb_x, a->mb_y);
00202         }
00203     }
00204 
00205     p->quality= a->qscale * FF_QP2LAMBDA;
00206     memset(p->qscale_table, a->qscale, a->mb_width);
00207 
00208     *picture   = a->picture;
00209     *data_size = sizeof(AVPicture);
00210 
00211     return (get_bits_count(&a->gb)+31)/32*4;
00212 }
00213 
00214 static av_cold void mdec_common_init(AVCodecContext *avctx){
00215     MDECContext * const a = avctx->priv_data;
00216 
00217     dsputil_init(&a->dsp, avctx);
00218 
00219     a->mb_width   = (avctx->coded_width  + 15) / 16;
00220     a->mb_height  = (avctx->coded_height + 15) / 16;
00221 
00222     avcodec_get_frame_defaults(&a->picture);
00223     avctx->coded_frame= &a->picture;
00224     a->avctx= avctx;
00225 }
00226 
00227 static av_cold int decode_init(AVCodecContext *avctx){
00228     MDECContext * const a = avctx->priv_data;
00229     AVFrame *p= &a->picture;
00230 
00231     mdec_common_init(avctx);
00232     ff_mpeg12_init_vlcs();
00233     ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
00234 
00235     if( avctx->idct_algo == FF_IDCT_AUTO )
00236         avctx->idct_algo = FF_IDCT_SIMPLE;
00237     p->qstride= 0;
00238     p->qscale_table= av_mallocz(a->mb_width);
00239     avctx->pix_fmt= PIX_FMT_YUVJ420P;
00240 
00241     return 0;
00242 }
00243 
00244 static av_cold int decode_init_thread_copy(AVCodecContext *avctx){
00245     MDECContext * const a = avctx->priv_data;
00246     AVFrame *p = (AVFrame*)&a->picture;
00247 
00248     avctx->coded_frame= p;
00249     a->avctx= avctx;
00250 
00251     p->qscale_table= av_mallocz(a->mb_width);
00252 
00253     return 0;
00254 }
00255 
00256 
00257 static av_cold int decode_end(AVCodecContext *avctx){
00258     MDECContext * const a = avctx->priv_data;
00259 
00260     if(a->picture.data[0])
00261         avctx->release_buffer(avctx, &a->picture);
00262     av_freep(&a->bitstream_buffer);
00263     av_freep(&a->picture.qscale_table);
00264     a->bitstream_buffer_size=0;
00265 
00266     return 0;
00267 }
00268 
00269 AVCodec ff_mdec_decoder = {
00270     .name           = "mdec",
00271     .type           = AVMEDIA_TYPE_VIDEO,
00272     .id             = CODEC_ID_MDEC,
00273     .priv_data_size = sizeof(MDECContext),
00274     .init           = decode_init,
00275     .close          = decode_end,
00276     .decode         = decode_frame,
00277     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
00278     .long_name= NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
00279     .init_thread_copy= ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)
00280 };
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