In this video tutorial I show how to Synchronise your Audio if it does not match the video component using Sony Vegas Movie Studio HD Platinum 10.
Two Types of Audio Synchronization Problems
#1 Audio becomes stretched
There is a technique/tool called "elastique" which you apply to the audio track. With this tool you can stretch or shrink the length of the audio track, so that it becomes back in "sync" synchronisation with your Video. This is the type of audio sync problem that I show how to fix in the video tutorial.
#2 Audio drops out of Registration
The second type of audio synchronization problem you may encounter is where the Video Stream and Audio Stream slip out of basic sync. If you zoom right into the clip on timeline and have a look at the beginning or end of the video, the Video will either be stepped slightly forward or behind the Audio track. You can temporarily un-group the Video from Audio using the "Ignore Event Grouping" function, and then just drag one or the other stream slightly, until they line up underneath each other at either end.
You may have to jiggle this every so silghtly by a few frames to get it precisely back in Sync. Just keep playing back a small section and watch/listen to someone speaking if available in the clip.
Once you have finished remember to re-group the Video and Audio back together, otherwise you can end up in a bigger mess than what you started with.
Here are some screen shots showing what to do