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/*
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 * PSX MDEC codec
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 * Copyright (c) 2003 Michael Niedermayer
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 *
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 * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
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 */
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/**
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 * @file mdec.c
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 * PSX MDEC codec.
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 * This is very similar to intra only MPEG1.
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 */
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#include "avcodec.h"
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#include "dsputil.h"
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#include "mpegvideo.h"
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//#undef NDEBUG
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//#include <assert.h>
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typedef struct MDECContext{
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    AVCodecContext *avctx;
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    DSPContext dsp;
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    AVFrame picture;
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    PutBitContext pb;
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    GetBitContext gb;
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    ScanTable scantable;
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    int version;
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    int qscale;
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    int last_dc[3];
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    int mb_width;
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    int mb_height;
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    int mb_x, mb_y;
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    DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
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    DECLARE_ALIGNED_8(uint16_t, intra_matrix[64]);
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    DECLARE_ALIGNED_8(int, q_intra_matrix[64]);
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    uint8_t *bitstream_buffer;
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    unsigned int bitstream_buffer_size;
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    int block_last_index[6];
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} MDECContext;
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//very similar to mpeg1
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static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
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{
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    int level, diff, i, j, run;
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    int component;
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    RLTable *rl = &rl_mpeg1;
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    uint8_t * const scantable= a->scantable.permutated;
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    const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
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    const int qscale= a->qscale;
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    /* DC coef */
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    if(a->version==2){
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        block[0]= 2*get_sbits(&a->gb, 10) + 1024;
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    }else{
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        component = (n <= 3 ? 0 : n - 4 + 1);
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        diff = decode_dc(&a->gb, component);
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        if (diff >= 0xffff)
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            return -1;
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        a->last_dc[component]+= diff;
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        block[0] = a->last_dc[component]<<3;
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    }
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    i = 0;
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    {
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        OPEN_READER(re, &a->gb);
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        /* now quantify & encode AC coefs */
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        for(;;) {
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            UPDATE_CACHE(re, &a->gb);
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            GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
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            if(level == 127){
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                break;
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            } else if(level != 0) {
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                i += run;
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                j = scantable[i];
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                level= (level*qscale*quant_matrix[j])>>3;
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//                level= (level-1)|1;
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                level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
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                LAST_SKIP_BITS(re, &a->gb, 1);
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            } else {
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                /* escape */
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                run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
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                UPDATE_CACHE(re, &a->gb);
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                level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
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                i += run;
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                j = scantable[i];
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                if(level<0){
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                    level= -level;
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                    level= (level*qscale*quant_matrix[j])>>3;
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                    level= (level-1)|1;
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                    level= -level;
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                }else{
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                    level= (level*qscale*quant_matrix[j])>>3;
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                    level= (level-1)|1;
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                }
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            }
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            if (i > 63){
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                av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
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                return -1;
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            }
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            block[j] = level;
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        }
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        CLOSE_READER(re, &a->gb);
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    }
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    a->block_last_index[n] = i;
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    return 0;
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}
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static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
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    int i;
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    const int block_index[6]= {5,4,0,1,2,3};
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    a->dsp.clear_blocks(block[0]);
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    for(i=0; i<6; i++){
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        if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
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            return -1;
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    }
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    return 0;
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}
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static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
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    DCTELEM (*block)[64]= a->block;
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    int linesize= a->picture.linesize[0];
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    uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
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    uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
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    uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
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    a->dsp.idct_put(dest_y                 , linesize, block[0]);
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    a->dsp.idct_put(dest_y              + 8, linesize, block[1]);
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    a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
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    a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
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    if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
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        a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
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        a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
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    }
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}
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static int decode_frame(AVCodecContext *avctx,
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                        void *data, int *data_size,
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                        uint8_t *buf, int buf_size)
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{
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    MDECContext * const a = avctx->priv_data;
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    AVFrame *picture = data;
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    AVFrame * const p= (AVFrame*)&a->picture;
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    int i;
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    if(p->data[0])
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        avctx->release_buffer(avctx, p);
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    p->reference= 0;
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    if(avctx->get_buffer(avctx, p) < 0){
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        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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        return -1;
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    }
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    p->pict_type= I_TYPE;
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    p->key_frame= 1;
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    a->last_dc[0]=
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    a->last_dc[1]=
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    a->last_dc[2]= 0;
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    a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
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    for(i=0; i<buf_size; i+=2){
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        a->bitstream_buffer[i]  = buf[i+1];
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        a->bitstream_buffer[i+1]= buf[i  ];
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    }
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    init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
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    /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
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    skip_bits(&a->gb, 32);
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    a->qscale=  get_bits(&a->gb, 16);
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    a->version= get_bits(&a->gb, 16);
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//    printf("qscale:%d (0x%X), version:%d (0x%X)\n", a->qscale, a->qscale, a->version, a->version);
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    for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
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        for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
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            if( decode_mb(a, a->block) <0)
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                return -1;
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            idct_put(a, a->mb_x, a->mb_y);
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        }
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    }
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//    p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;
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//    memset(p->qscale_table, p->quality, p->qstride*a->mb_height);
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    *picture= *(AVFrame*)&a->picture;
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    *data_size = sizeof(AVPicture);
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    emms_c();
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    return (get_bits_count(&a->gb)+31)/32*4;
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}
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static void mdec_common_init(AVCodecContext *avctx){
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    MDECContext * const a = avctx->priv_data;
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    dsputil_init(&a->dsp, avctx);
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    a->mb_width   = (avctx->coded_width  + 15) / 16;
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    a->mb_height  = (avctx->coded_height + 15) / 16;
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    avctx->coded_frame= (AVFrame*)&a->picture;
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    a->avctx= avctx;
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}
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static int decode_init(AVCodecContext *avctx){
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    MDECContext * const a = avctx->priv_data;
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    AVFrame *p= (AVFrame*)&a->picture;
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    mdec_common_init(avctx);
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    init_vlcs();
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    ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
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/*
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    for(i=0; i<64; i++){
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        int index= ff_zigzag_direct[i];
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        a->intra_matrix[i]= 64*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;
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    }
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*/
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    p->qstride= a->mb_width;
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    p->qscale_table= av_mallocz( p->qstride * a->mb_height);
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    avctx->pix_fmt= PIX_FMT_YUV420P;
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    return 0;
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}
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static int decode_end(AVCodecContext *avctx){
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    MDECContext * const a = avctx->priv_data;
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    av_freep(&a->bitstream_buffer);
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    av_freep(&a->picture.qscale_table);
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    a->bitstream_buffer_size=0;
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    return 0;
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}
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AVCodec mdec_decoder = {
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    "mdec",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_MDEC,
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    sizeof(MDECContext),
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    decode_init,
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    NULL,
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    decode_end,
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    decode_frame,
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    CODEC_CAP_DR1,
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};
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