No Audio for MP4 on Sony Vegas 9.0 Pro

[samthegreek]

So I have Sony Vegas 9.0 Pro, and when I open up anything that is in an MP4 format, there is no audio. There isn't even a track for it - it's just one video track and that's all. The MP4s play fine on my Quicktime player - it's just Sony Vegas that has the issue.

I have Windows with Vista (in case that's important).

Please note that I'm pretty stupid when it comes to computer stuff, so if you would like to help me, could you please try to keep the directions simple?

[Enigma]

1.Don't edit lossy formats(MP4,AVI's(XviD,DivX compressed,WMV,MPEG1,MPEG2 etc..)
2.Convert them to lagarith/huffyuv(warning for big file size)

Any more question can be found in:

Read ErMaC and AbsoluteDestiny's Friendly Amv Guides Lovingly Overhauled Largely by Zarxrax) :

http://www.animemusicvideos.org/guides/avtech3/

[Iamshadowkiller]

Related or unrelated to this, if you want a quick fix for your mp4 audio needs. Say, you need the audio from an mp4 file and don't want to go buying things like they do in the movies you can install Dbpoweramp Trial version along with their provided m4a codec and you should be able to right click on the mp4 right from the context menu and convert to whatever.