Function decode_slice

libavcodec/h263dec.c:152–329

}

static int decode_slice(MpegEncContext *s){
    const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
    const int mb_size= 16>>s->avctx->lowres;
    s->last_resync_gb= s->gb;
    s->first_slice_line= 1;

    s->resync_mb_x= s->mb_x;
    s->resync_mb_y= s->mb_y;

    ff_set_qscale(s, s->qscale);

    if (s->avctx->hwaccel) {
        const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
        const uint8_t *end  = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
        skip_bits_long(&s->gb, 8*(end - start));
        return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
    }

    if(s->partitioned_frame){
        const int qscale= s->qscale;

        if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
            if(ff_mpeg4_decode_partitions(s) < 0)
                return -1;
        }

        /* restore variables which were modified */
        s->first_slice_line=1;
        s->mb_x= s->resync_mb_x;
        s->mb_y= s->resync_mb_y;
        ff_set_qscale(s, qscale);
    }

    for(; s->mb_y < s->mb_height; s->mb_y++) {
        /* per-row end of slice checks */
        if(s->msmpeg4_version){
            if(s->resync_mb_y + s->slice_height == s->mb_y){
                ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);

                return 0;
            }
        }

        if(s->msmpeg4_version==1){
            s->last_dc[0]=
            s->last_dc[1]=
            s->last_dc[2]= 128;
        }

        ff_init_block_index(s);
        for(; s->mb_x < s->mb_width; s->mb_x++) {
            int ret;

            ff_update_block_index(s);

            if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
                s->first_slice_line=0;
            }