Sony Vegas Pro 9 – No audio on imported MP4 files?

[Stephen Mann]

Then, I am convinced that it is a codec issue. Try updating your display adapter codec – believe it or not, there are audio components in there.

As a last resort, you may want to use a third-party program to convert it to something more editor friendly. I use Handbrake when a client gives me a video file that Vegas just refuses to play nice. If Handbrake won’t do it, I fall back to Wondershare Video Converter.

Steve Mann
MannMade Digital Video
http://www.mmdv.com