st = s->streams[0];
left= wav->data_end - url_ftell(&s->pb);
if(left <= 0){
left = find_tag(&(s->pb), MKTAG('d', 'a', 't', 'a'));
if (left < 0) {
st = s->streams[0];
left= wav->data_end - url_ftell(&s->pb);
if(left <= 0){
left = find_tag(&(s->pb), MKTAG('d', 'a', 't', 'a'));
if (left < 0) {