Boost volume on a video for iPhone?

[Stephen Hart]

I listen to a lot of lectures on my iPhone (and my iPod before that).

Sometimes a given lecture is recorded at too low a volume level, even if I crank my car radio up. (For some reason, the AUX input isn't as loud as other inputs.)

In the old days, I'd copy an audio track out to Sound Studio and boost the volume on the track, then put it back into iTunes.

But now I'm often getting videos. (Many universities are not putting both audio and video on iTunesU.)
Getting info in iTunes and boosting the volume doesn't work. That's apparently only for playing within iTunes.

This is doable in iMovie, I guess. (I haven't tested in the car yet.) Anyone have a simpler method?

[Ray Bentsen]

Audacity is an open source sound editor that should do the job: http://audacity.sourceforge.net/

Just open the file to be edited (from iTunes is an option) and then choose Amplify from the Effect menu. (see screenshot)

[Stephen Hart]

The problem is that this is a movie, not audio only. I tried Sound Studio, a sound editor like Audacity. It opens the mp4, has no problem amping the sound, and dutifully saves out a sound-only file with the same name, overwriting the video.

I was able to boost the audio without affecting the video in iMovie. And I could rename and move the .mov file that iMovie saves into iTunes. It drops into the iTunes U section, and even retains its identity within the collection. It shows up as checked when I look at my connected iPhone under the iTunes U tab. It's one of the seven items in that collection. Of course I hit Apply after making changes.

But, weirdly, it never makes it to my iPhone. It just doesn't show up there at all.

In this particular case, I can live with the volume as is, but it'd be nice to figure this out.