Just got around to testing this. I have found a plugin clash using the Youtube video embedding.
Posting
http://www.youtube.com/watch?v=m2OC5Z1Fii8
Gives me this
[YOUTUBEvid]m2OC5Z1Fii8[/youtubevid]
But doesn't actually embed. Obviously your mod is working but isn't showing.
Through the process of elimination however i tracked it down to a conflict with the
Embed XHTML valid YouTube and Google Video into your posts plugin
https://vborg.vbsupport.ru/showthread.php?t=130868
If i disable his plugin and repost the same link, yours embeds as it should.
Whats bizarre is that viper uses the bbcode
[YOUTUBE]http://www.youtube.com/watch?v=m2OC5Z1Fii8[/YOUTUBE]
So its not touching your BBCODE at all. But i've now tried several times and the only way i can get your embed to work is by disabling his. Although thats an option, we do have many youtubes already embedded using his BBCODE.
Any ideas for a fixable solution ?
I tried with myspace videos and they parse and emded fine.