HI All

I am afraid you are not going to have much luck with this.
If the audio is already embedded in the video you can then only edit as one composite clip. As would be the case in a series of clips from a camcorder.

As you say some not all, video editors allow you to overlay a separate sound track as merged or as replacement for the original sound the video will then need to be re rendered to embed this extra sound.
The separate sound track can often have simple edits such as fade in and out and
cross fading imposed.
Whilst you can work on the track this way
What you wont find are any ways of say stretching or shortening the sound and applying the necessary pitch changing to keep in tune.

In this respect the most you can do, if you have a separate sound track to work on is cut the video into shorter clips and trim or stretch the video clip to match the length of the Audio. The eye as fare more tolerant than the ear, I use this method sometimes to get scene changes on the beat.
Even this job is far easier if the video is a series of stills and not rolling action.
But cross faded sound over video cross faded transition can be very effective.

Just my thoughts
Mike

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