static int decode_cpe(AACContext *ac, GetBitContext *gb, ChannelElement *cpe)
{
    int i, ret, common_window, ms_present = 0;
    int eld_syntax = ac->oc[1].m4ac.object_type == AOT_ER_AAC_ELD;

    common_window = eld_syntax || get_bits1(gb);
    if (common_window) {
        if (decode_ics_info(ac, &cpe->ch[0].ics, gb))
            return AVERROR_INVALIDDATA;
        i = cpe->ch[1].ics.use_kb_window[0];
        cpe->ch[1].ics = cpe->ch[0].ics;
        cpe->ch[1].ics.use_kb_window[1] = i;
        if (cpe->ch[1].ics.predictor_present &&
            (ac->oc[1].m4ac.object_type != AOT_AAC_MAIN))
            if ((cpe->ch[1].ics.ltp.present = get_bits(gb, 1)))
                decode_ltp(&cpe->ch[1].ics.ltp, gb, cpe->ch[1].ics.max_sfb);
        ms_present = get_bits(gb, 2);
        if (ms_present == 3) {
            av_log(ac->avctx, AV_LOG_ERROR, "ms_present = 3 is reserved.\n");
            return AVERROR_INVALIDDATA;
        } else if (ms_present)
            decode_mid_side_stereo(cpe, gb, ms_present);
    }
    if ((ret = decode_ics(ac, &cpe->ch[0], gb, common_window, 0)))
        return ret;
    if ((ret = decode_ics(ac, &cpe->ch[1], gb, common_window, 0)))
        return ret;

    if (common_window) {
        if (ms_present)
            apply_mid_side_stereo(ac, cpe);
        if (ac->oc[1].m4ac.object_type == AOT_AAC_MAIN) {
            apply_prediction(ac, &cpe->ch[0]);
            apply_prediction(ac, &cpe->ch[1]);
        }
    }

    apply_intensity_stereo(ac, cpe, ms_present);
    return 0;
}
Unknown