ffmpeg / libavcodec / mdec.c @ 71160c55
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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 library 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 of the License, or (at your option) any later version.

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*

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* This library 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 this library; if not, write to the Free Software

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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 021111307 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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DCTELEM __align8 block[6][64]; 
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uint16_t __align8 intra_matrix[64];

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int __align8 q_intra_matrix[64]; 
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uint8_t *bitstream_buffer; 
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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= (level1)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= (level1)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= (level1)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, "actex 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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