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ffmpeg / libavcodec / h263dec.c @ bb71e317

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/*
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 * H263 decoder
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 * Copyright (c) 2001 Gerard Lantau.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program 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
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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 */
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "dsputil.h"
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#include "avcodec.h"
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#include "mpegvideo.h"
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//#define DEBUG
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static int h263_decode_init(AVCodecContext *avctx)
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{
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    MpegEncContext *s = avctx->priv_data;
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    int i;
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    s->avctx = avctx;
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    s->out_format = FMT_H263;
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    s->width = avctx->width;
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    s->height = avctx->height;
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    /* select sub codec */
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    switch(avctx->codec->id) {
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    case CODEC_ID_H263:
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        s->gob_number = 0;
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        s->first_gob_line = 0;
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        break;
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    case CODEC_ID_MPEG4:
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        s->time_increment_bits = 4; /* default value for broken headers */
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        s->h263_pred = 1;
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        s->has_b_frames = 1; //default, might be overriden in the vol header during header parsing
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        break;
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    case CODEC_ID_MSMPEG4V1:
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        s->h263_msmpeg4 = 1;
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        s->h263_pred = 1;
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        s->msmpeg4_version=1;
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        break;
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    case CODEC_ID_MSMPEG4V2:
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        s->h263_msmpeg4 = 1;
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        s->h263_pred = 1;
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        s->msmpeg4_version=2;
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        break;
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    case CODEC_ID_MSMPEG4V3:
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        s->h263_msmpeg4 = 1;
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        s->h263_pred = 1;
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        s->msmpeg4_version=3;
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        break;
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    case CODEC_ID_WMV1:
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        s->h263_msmpeg4 = 1;
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        s->h263_pred = 1;
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        s->msmpeg4_version=4;
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        break;
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    case CODEC_ID_H263I:
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        s->h263_intel = 1;
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        break;
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    default:
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        return -1;
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    }
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    s->codec_id= avctx->codec->id;
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    avctx->mbskip_table= s->mbskip_table;
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    /* for h263, we allocate the images after having read the header */
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    if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
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        if (MPV_common_init(s) < 0)
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            return -1;
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    if (s->h263_msmpeg4)
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        msmpeg4_decode_init_vlc(s);
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    else
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        h263_decode_init_vlc(s);
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    return 0;
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}
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static int h263_decode_end(AVCodecContext *avctx)
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{
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    MpegEncContext *s = avctx->priv_data;
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    MPV_common_end(s);
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    return 0;
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}
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static int h263_decode_frame(AVCodecContext *avctx, 
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                             void *data, int *data_size,
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                             UINT8 *buf, int buf_size)
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{
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    MpegEncContext *s = avctx->priv_data;
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    int ret;
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    AVPicture *pict = data; 
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#ifdef DEBUG
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    printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
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    printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
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#endif
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    s->hurry_up= avctx->hurry_up;
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    /* no supplementary picture */
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    if (buf_size == 0) {
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        *data_size = 0;
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        return 0;
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    }
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    if(s->bitstream_buffer_size) //divx 5.01+ frame reorder
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        init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size);
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    else
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        init_get_bits(&s->gb, buf, buf_size);
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    /* let's go :-) */
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    if (s->h263_msmpeg4) {
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        ret = msmpeg4_decode_picture_header(s);
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    } else if (s->h263_pred) {
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        ret = mpeg4_decode_picture_header(s);
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        s->has_b_frames= !s->low_delay;
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    } else if (s->h263_intel) {
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        ret = intel_h263_decode_picture_header(s);
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    } else {
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        ret = h263_decode_picture_header(s);
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    }
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        /* After H263 & mpeg4 header decode we have the height, width,*/
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        /* and other parameters. So then we could init the picture   */
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        /* FIXME: By the way H263 decoder is evolving it should have */
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        /* an H263EncContext                                         */
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    if (!s->context_initialized) {
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        avctx->width = s->width;
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        avctx->height = s->height;
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        avctx->aspect_ratio_info= s->aspect_ratio_info;
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        if (MPV_common_init(s) < 0)
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            return -1;
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    } else if (s->width != avctx->width || s->height != avctx->height) {
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        /* H.263 could change picture size any time */
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        MPV_common_end(s);
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        if (MPV_common_init(s) < 0)
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            return -1;
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    }
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    if(ret==FRAME_SKIPED) return 0;
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    if (ret < 0)
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        return -1;
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    /* skip b frames if we dont have reference frames */
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    if(s->num_available_buffers<2 && s->pict_type==B_TYPE) return 0;
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    /* skip b frames if we are in a hurry */
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    if(s->hurry_up && s->pict_type==B_TYPE) return 0;
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    MPV_frame_start(s);
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#ifdef DEBUG
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    printf("qscale=%d\n", s->qscale);
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#endif
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    /* decode each macroblock */
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    s->block_wrap[0]=
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    s->block_wrap[1]=
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    s->block_wrap[2]=
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    s->block_wrap[3]= s->mb_width*2 + 2;
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    s->block_wrap[4]=
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    s->block_wrap[5]= s->mb_width + 2;
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    for(s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) {
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        /* Check for GOB headers on H.263 */
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        /* FIXME: In the future H.263+ will have intra prediction */
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        /* and we are gonna need another way to detect MPEG4      */
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        if (s->mb_y && !s->h263_pred) {
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            s->first_gob_line = h263_decode_gob_header(s);
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        }
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        s->block_index[0]= s->block_wrap[0]*(s->mb_y*2 + 1) - 1;
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        s->block_index[1]= s->block_wrap[0]*(s->mb_y*2 + 1);
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        s->block_index[2]= s->block_wrap[0]*(s->mb_y*2 + 2) - 1;
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        s->block_index[3]= s->block_wrap[0]*(s->mb_y*2 + 2);
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        s->block_index[4]= s->block_wrap[4]*(s->mb_y + 1)                    + s->block_wrap[0]*(s->mb_height*2 + 2);
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        s->block_index[5]= s->block_wrap[4]*(s->mb_y + 1 + s->mb_height + 2) + s->block_wrap[0]*(s->mb_height*2 + 2);
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        for(s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) {
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            s->block_index[0]+=2;
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            s->block_index[1]+=2;
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            s->block_index[2]+=2;
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            s->block_index[3]+=2;
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            s->block_index[4]++;
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            s->block_index[5]++;
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#ifdef DEBUG
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            printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y);
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#endif
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            //fprintf(stderr,"\nFrame: %d\tMB: %d",avctx->frame_number, (s->mb_y * s->mb_width) + s->mb_x);
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            /* DCT & quantize */
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            if (s->h263_pred && s->msmpeg4_version!=2) {
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                h263_dc_scale(s);
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            } else {
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                /* default quantization values */
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                s->y_dc_scale = 8;
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                s->c_dc_scale = 8;
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            }
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            clear_blocks(s->block[0]);
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            s->mv_dir = MV_DIR_FORWARD;
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            s->mv_type = MV_TYPE_16X16; 
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            if (s->h263_msmpeg4) {
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                if (msmpeg4_decode_mb(s, s->block) < 0) {
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                    fprintf(stderr,"\nError at MB: %d\n", (s->mb_y * s->mb_width) + s->mb_x);
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                    return -1;
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                }
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            } else {
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                if (h263_decode_mb(s, s->block) < 0) {
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                    fprintf(stderr,"\nError at MB: %d\n", (s->mb_y * s->mb_width) + s->mb_x);
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                    return -1;
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                }
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            }
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            MPV_decode_mb(s, s->block);
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        }
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        if (    avctx->draw_horiz_band 
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            && (s->num_available_buffers>=1 || (!s->has_b_frames)) ) {
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            UINT8 *src_ptr[3];
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            int y, h, offset;
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            y = s->mb_y * 16;
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            h = s->height - y;
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            if (h > 16)
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                h = 16;
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            offset = y * s->linesize;
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            if(s->pict_type==B_TYPE || (!s->has_b_frames)){
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                src_ptr[0] = s->current_picture[0] + offset;
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                src_ptr[1] = s->current_picture[1] + (offset >> 2);
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                src_ptr[2] = s->current_picture[2] + (offset >> 2);
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            } else {
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                src_ptr[0] = s->last_picture[0] + offset;
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                src_ptr[1] = s->last_picture[1] + (offset >> 2);
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                src_ptr[2] = s->last_picture[2] + (offset >> 2);
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            }
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            avctx->draw_horiz_band(avctx, src_ptr, s->linesize,
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                                   y, s->width, h);
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        }
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    }
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    if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
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        if(msmpeg4_decode_ext_header(s, buf_size) < 0) return -1;
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    /* divx 5.01+ bistream reorder stuff */
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    if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0){
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        int current_pos= get_bits_count(&s->gb)/8;
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        if(   buf_size - current_pos > 5 
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           && buf_size - current_pos < BITSTREAM_BUFFER_SIZE){
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            memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
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            s->bitstream_buffer_size= buf_size - current_pos;
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        }
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    }else
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        s->bitstream_buffer_size=0;
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    MPV_frame_end(s);
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    if(s->pict_type==B_TYPE || (!s->has_b_frames)){
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        pict->data[0] = s->current_picture[0];
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        pict->data[1] = s->current_picture[1];
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        pict->data[2] = s->current_picture[2];
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    } else {
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        pict->data[0] = s->last_picture[0];
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        pict->data[1] = s->last_picture[1];
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        pict->data[2] = s->last_picture[2];
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    }
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    pict->linesize[0] = s->linesize;
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    pict->linesize[1] = s->linesize / 2;
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    pict->linesize[2] = s->linesize / 2;
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    avctx->quality = s->qscale;
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    /* Return the Picture timestamp as the frame number */
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    /* we substract 1 because it is added on utils.c    */
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    avctx->frame_number = s->picture_number - 1;
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    /* dont output the last pic after seeking 
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       note we allready added +1 for the current pix in MPV_frame_end(s) */
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    if(s->num_available_buffers>=2 || (!s->has_b_frames))
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        *data_size = sizeof(AVPicture);
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    return buf_size;
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}
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AVCodec mpeg4_decoder = {
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    "mpeg4",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_MPEG4,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec h263_decoder = {
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    "h263",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_H263,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec msmpeg4v1_decoder = {
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    "msmpeg4v1",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_MSMPEG4V1,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec msmpeg4v2_decoder = {
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    "msmpeg4v2",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_MSMPEG4V2,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec msmpeg4v3_decoder = {
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    "msmpeg4",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_MSMPEG4V3,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec wmv1_decoder = {
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    "wmv1",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_WMV1,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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AVCodec h263i_decoder = {
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    "h263i",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_H263I,
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    sizeof(MpegEncContext),
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    h263_decode_init,
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    NULL,
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    h263_decode_end,
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    h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND,
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};
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