Gary,
I have a MacPro 3.0Ghz first generation using OS X 10.5.8 with Quicktime 7.6.6 (1674) and iTunes 9. I have saved several video files with “mpg” file ext. format. The play perfectly with VLP player but I have no sound in either Quicktime or iTunes. Quicktime is my default player. What do I need to do to have audio in Quicktime and iTunes.
— Don
How did you create these videos? It sounds like you are using a non-standard audio compression setting. Since you already use VLC, then just export them from there in a more typical QuickTime/mp4 format and they should play fine in QuickTime.