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* Copyright (c) 2003 Michael Niedermayer
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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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* 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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* 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 02111-1307 USA
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* based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
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* This is very similar to intra only MPEG1.
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#include "mpegvideo.h"
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typedef struct MDECContext{
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AVCodecContext *avctx;
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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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//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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int level, diff, i, j, run;
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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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block[0]= 2*get_sbits(&a->gb, 10) + 1024;
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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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a->last_dc[component]+= diff;
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block[0] = a->last_dc[component]<<3;
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OPEN_READER(re, &a->gb);
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/* now quantify & encode AC coefs */
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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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} else if(level != 0) {
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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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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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level= (level*qscale*quant_matrix[j])>>3;
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level= (level*qscale*quant_matrix[j])>>3;
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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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CLOSE_READER(re, &a->gb);
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a->block_last_index[n] = i;
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static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
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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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if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0)
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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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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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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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avctx->release_buffer(avctx, p);
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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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p->pict_type= I_TYPE;
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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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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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idct_put(a, a->mb_x, a->mb_y);
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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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return (get_bits_count(&a->gb)+31)/32*4;
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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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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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ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
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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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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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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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AVCodec mdec_decoder = {
added
removed
adm_lavcodec/mdec.c
