IS there any way in QT Pro 7 to do an overwrite edit? I have a movie with a video and ac3 sound track. I want to add a AAC sound track that is the same duration of the video track. So the movie would then have two audio tracks., both the same duration as the video track.
If I'm understanding what you want to do correctly, then this is possible using QT7 Pro.
You need to isolate the track of audio you want to add to your movie in a separate QT player window. So either open the audio file directly in QuickTime, or open the video it's embedded in, go into the "Movie Properties" menu (Command + J), select the audio track you want and then hit "Extract."
With your newly isolated audio track window active, select all (Command + A) and copy to the clipboard. Activate your destination movie, select all again, and go to "Edit...Add To Movie" (Should be Command + Option + V). You should now see two audio tracks in your destination movie properties.
Keep in mind that you'll have to save or export this new dual audio track movie as a new quicktime movie