m->stream_index = strtol(arg, (char **)&p, 0);
m->stream_index = strtol(p, (char **)&p, 0);
void opt_map(const char *arg){    AVStreamMap *m;    const char *p;    p = arg;    m = &stream_maps[nb_stream_maps++];    m->file_index = strtol(arg, (char **)&p, 0);    if (*p)        p++;    m->stream_index = strtol(arg, (char **)&p, 0);}