These are used in Youtube formats
@ -1831,6 +1831,8 @@ def mimetype2ext(mt):
'x-ms-wmv': 'wmv',
'x-mp4-fragmented': 'mp4',
'ttml+xml': 'ttml',
'3gpp': '3gp',
'x-flv': 'flv',
}.get(res, res)