how to add commentary over dvd audio?

[Denvers Dawgs]

How would I go about adding a second audio over the original dvd audio, and have both play? Most likely either lowering the volume on the dvd audio or upping the volume on the commentary audio. The audio commentary I have is in mp3 form or riff form.

Any ideas. Also free would be great!

[Nitemare]

Okay... AFAIK, any second audio track is completely separate from the original. If you want a commentary over the movie sound, you'd need to copy the movie audio to another track and then add your comments over it using an audio editor.

You could author this using DVDAuthorGUI (free) or something similar... any authoring package that supports multiple audio tracks. Freeware audio editors are available... check the TOOLS section on the left.

[AlanHK]

I use this method in Audacity (1.3.3 beta):

Load the original soundtrack (you may need to convert it to wave).

Load your commentary track too -- now you will see four tracks , L& R for each (unless you have mono).

First check the commentary track. If it seems quiet, boost the volume and/or normalise it.

Now select original soundtrack

You can see the waveform, so zoom in to a louder section of the original.

On Effects menu: choose Compressor.
You want to reduce the volume of loud passages while not changing quiet ones. I use a setting like:
Threshold -29; ratio 10:1
* uncheck "normalise", otherwise the volume will be boosted to compensate for the quieter track.

Then select a few seconds and apply the effect then play it. The commentary track will be audible too (if it's not muted). If it seems okay -- commentary audible and original not too quiet, then undo and select all, apply the effect to the entire track.

Play it again. If you're happy with it, export the project as WAVE. This will mix it in. Now convert it to AC3, or whatever (ffmpeg, BeSweet, etc).

I've done this to add podcast commentary tracks to TV episode compilations.


In most DVD authoring apps you can add alternate soundtracks, I generally label these commentary tracks as "German" lacking any better tag, just so I know which is which.

[guns1inger]

I use Vegas and a volume envelope so I can vary the main track audio up and down under the commentary when necessary