static int mpsub_probe(AVProbeData *p)
{
    const char *ptr     = p->buf;
    const char *ptr_end = p->buf + p->buf_size;

    while (ptr < ptr_end) {
        if (!memcmp(ptr, "FORMAT=TIME", 11))
            return AVPROBE_SCORE_EXTENSION;
        if (!memcmp(ptr, "FORMAT=", 7))
            return AVPROBE_SCORE_EXTENSION / 3;
        ptr += strcspn(ptr, "\n") + 1;
    }
    return 0;
}