Audio level changes in the middle of the movie

I just made a backup dvd testing out my new Benq1655. Anyway, the sound level drops a little bit and then goes back up to normal several times during the movie. Is this problem likely in the original dvd or a burner problem?

never mind. original dvd has it too.

Don’t give up just yet. Some programs able to back up discs also have this thing called “normalize audio” The ability to make more equal the highs and lows of sound. Given the number of programs I have I can’t remember which ones have it (have used the function before myself) but im sure someone else in here can zoom in on this like a rocket ship.

This normalized disc would be considered re mastering for a desired effect and not just a straight up copy.