val = show_bits(&s->gb, 15); if(val) return -1;
if ( !h->gob_start_code_skipped ){  val = show_bits(&s->gb, 15); if(val) return -1;
static int h261_decode_gob_header(H261Context *h){    unsigned int val;    MpegEncContext * const s = &h->s;        /* Check for GOB Start Code */    val = show_bits(&s->gb, 15);    if(val)        return -1;    /* We have a GBSC */    skip_bits(&s->gb, 16);    h->gob_number = get_bits(&s->gb, 4); /* GN */    s->qscale = get_bits(&s->gb, 5); /* GQUANT */    /* GEI */    while (get_bits1(&s->gb) != 0) {        skip_bits(&s->gb, 8);    }    if(s->qscale==0)        return -1;    // For the first transmitted macroblock in a GOB, MBA is the absolute address. For    // subsequent macroblocks, MBA is the difference between the absolute addresses of    // the macroblock and the last transmitted macroblock.    h->current_mba = 0;    h->mba_diff = 0;    return 0;}