tag = avio_rl32(pb);
switch (tag) {
case MKTAG('a', 'c', 'T', 'L'):
if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
(ret = append_extradata(st->codecpar, pb, len + 12)) < 0)
tag = avio_rl32(pb);
switch (tag) {
case MKTAG('a', 'c', 'T', 'L'):
if ((ret = avio_seek(pb, -8, SEEK_CUR)) < 0 ||
(ret = append_extradata(st->codecpar, pb, len + 12)) < 0)