static int aa_probe(const AVProbeData *p)
{
    uint8_t *buf = p->buf;

    // first 4 bytes are file size, next 4 bytes are the magic
    if (AV_RB32(buf+4) != AA_MAGIC)
        return 0;

    return AVPROBE_SCORE_MAX / 2;
}
static int aa_probe(const AVProbeData *p)
{
    uint8_t *buf = p->buf;

     
    if (AV_RB32(buf+4) != AA_MAGIC)
        return 0;

    return AVPROBE_SCORE_MAX / 2;
}