Ok I speak french so I'll do it easy to understand me.
I Use Vegas Pro 9.0c. In the preview video while editing (into the software, the timeline) .. when I press play, everything is sync. Everything is PERFECT.
When I render in AVI or MPEG2 or else, video and audio are not sync. I tired everything ... match the project with a media, verifying if the project has the same properties of the media, render as uncompressed.
I don't know if it may help ... my used files are in AVI. it's a music show (our show) split in two files that I "crossfare" in Vegas pro to make it feel like one piece and not two (so we can barely hear the gap between) ... to do this, I uncheck "quantize timeline" to match the waveform togheter (because with the quantize, it was not easy to be specific) and after I enable the "quantize option" when finished. I used about 16 markers to make future chapters in DVD and I used a fade out at the end of the show.
Another Question despite the other one : When I watch my 2 source files (before being edited) in windows media player or else, I can see that it's a widescreen video into a 720X480 window ... you know what I mean? The box is 720X480 but the video is in the middle and is widescreen (so there's a black rectangle at the top and at the bottom of the video). But when I insert those 2 media files into vegas pro 9, it keeps them 720X480 but full screen ... so the software fills those 2 rectangles with the video .... I've tried many options to change this but not able ... even in the preview than in the render ... the most important is obviously the render.