Thanks...

I can edit the MP3 file, and trim the end/beginning as necessary, but that gets a bit time-consuming.

I thought about this a bit after my post, and I guess the best way is trim (with PowerPoint) the end of the background MP3 at the point where my video/audio clip begins.

Then I would re-insert the same MP3 after that video/audio clip ends, and then PowerPoint trim the beginning of that inserted MP3 to match up with where the other MP3 section ends.

Also, not easy, but better for a bit of trial-and-error on end/begin of MP3 sections.


The only problem is that PowerPoint "trim" does not always seem to work.