Function ff_msmpeg4_decode_block

libavcodec/msmpeg4dec.c:612–800

}

int ff_msmpeg4_decode_block(MSMP4DecContext *const ms, int16_t * block,
                              int n, int coded, const uint8_t *scan_table)
{
    H263DecContext *const h = &ms->h;
    int level, i, last, run, run_diff;
    int dc_pred_dir = -1; //unused but its passed around, so it needs to be initialized
    const RLTable *rl;
    const RL_VLC_ELEM *rl_vlc;
    int qmul, qadd;

    if (h->c.mb_intra) {
        qmul=1;
        qadd=0;

        /* DC coef */
        level = msmpeg4_decode_dc(ms, n, &dc_pred_dir);

        if (level < 0){
            av_log(h->c.avctx, AV_LOG_ERROR, "dc overflow- block: %d qscale: %d//\n", n, h->c.qscale);
            if (h->c.inter_intra_pred)
                level = 0;
        }
        if (n < 4) {
            rl = &ff_rl_table[ms->rl_table_index];
            if (level > 256 * h->c.y_dc_scale) {
                av_log(h->c.avctx, AV_LOG_ERROR, "dc overflow+ L qscale: %d//\n", h->c.qscale);
                if (!h->c.inter_intra_pred)
                    return -1;
            }
        } else {
            rl = &ff_rl_table[3 + ms->rl_chroma_table_index];
            if (level > 256 * h->c.c_dc_scale) {
                av_log(h->c.avctx, AV_LOG_ERROR, "dc overflow+ C qscale: %d//\n", h->c.qscale);
                if (!h->c.inter_intra_pred)
                    return -1;
            }
        }
        block[0] = level;

        run_diff = h->c.msmpeg4_version >= MSMP4_WMV1;
        i = 0;
        if (!coded) {
            goto not_coded;
        }
        if (h->c.ac_pred) {
            if (dc_pred_dir == 0)
                scan_table = h->permutated_intra_v_scantable; /* left */
            else
                scan_table = h->permutated_intra_h_scantable; /* top */
        } else {
            scan_table = h->c.intra_scantable.permutated;
        }
        rl_vlc= rl->rl_vlc[0];
    } else {
        qmul = h->c.qscale << 1;
        qadd = (h->c.qscale - 1) | 1;
        i = -1;
        rl = &ff_rl_table[3 + ms->rl_table_index];