if (get_bits(&s->gb, 22) != 0x20)
if (get_bits(&s->gb, 22) != 0x20) { fprintf(stderr, "Bad picture start code\n");
int intel_h263_decode_picture_header(MpegEncContext *s){    int format;    /* picture header */    if (get_bits(&s->gb, 22) != 0x20)        return -1;    skip_bits(&s->gb, 8); /* picture timestamp */    if (get_bits1(&s->gb) != 1)        return -1;	/* marker */    if (get_bits1(&s->gb) != 0)        return -1;	/* h263 id */    skip_bits1(&s->gb);	/* split screen off */    skip_bits1(&s->gb);	/* camera  off */    skip_bits1(&s->gb);	/* freeze picture release off */    format = get_bits(&s->gb, 3);    if (format != 7)        return -1;    s->h263_plus = 0;    s->pict_type = I_TYPE + get_bits1(&s->gb);        s->unrestricted_mv = get_bits1(&s->gb);     s->h263_long_vectors = s->unrestricted_mv;    if (get_bits1(&s->gb) != 0)        return -1;	/* SAC: off */    if (get_bits1(&s->gb) != 0)        return -1;	/* advanced prediction mode: off */    if (get_bits1(&s->gb) != 0)        return -1;	/* not PB frame */    /* skip unknown header garbage */    skip_bits(&s->gb, 41);    s->qscale = get_bits(&s->gb, 5);    skip_bits1(&s->gb);	/* Continuous Presence Multipoint mode: off */    /* PEI */    while (get_bits1(&s->gb) != 0) {        skip_bits(&s->gb, 8);    }    s->f_code = 1;    return 0;}