No audio in iMovie

I'm trying to edit some video footage of a friend's kid, and I get audio in the video clips if I play them in Quicktime. Once they are imported into iMovie, however, the video plays just fine, but I have no audio. I have audio in iMovie from other video clips done with my camera. I know the sound settings are fine, because I've gone and dropped in my own files and the audio is top notch, so it's not a setting that I've toggled.

Any ideas? I do have Flip 4 mac, but that shouldn't come into play, should it? The files that have no audio in iMovie are mpegs.

Basically the audio/video need to be 2 separate tracks and your mpegs most probably are mixed as 1 file. This is called Multiplexed and De-Multiplexing the mpeg file using an app like MPEG2Works or similiar is the solution.

I found this article which will explain things:

http://docs.info.apple.com/article.html?artnum=42996

Try using this app to de-mux (de-multiplex) the mpeg:

http://www.versiontracker.com/dyn/moreinfo/macosx/20867

Thanks Marty. The mpegs in question aren't ones that I took, but were taken with a Sony Cybershot, according to my friend. I get audio on a wintel machine in Windows Media Player and in Windows Movie Maker. Seems both Windows programs play multiplexed video/audio files just fine.

I just tried importing some mpeg footage of mine into iMovie shot with my old Sony Cybershot, and I get the same result. No audio.

Any reason why iMovie must have de-muxed a/v? Perhaps it offers more control while editing?

Thanks for the heads up.

Dixon Deeper said:

Thanks Marty. The mpegs in question aren't ones that I took, but were taken with a Sony Cybershot, according to my friend. I get audio on a wintel machine in Windows Media Player and in Windows Movie Maker. Seems both Windows programs play multiplexed video/audio files just fine.

I just tried importing some mpeg footage of mine into iMovie shot with my old Sony Cybershot, and I get the same result. No audio.

Any reason why iMovie must have de-muxed a/v? Perhaps it offers more control while editing?

Thanks for the heads up.

Click to expand...

the Sony Cybershot compresses video as MPEG2 usually, and the resulting Quicktimes are muxed, the audio/video on one track. To edit you must separate them using one of the aforementioned programs. Playback in Media Player or Quicktime decompresses already, but just for playing purposes. You demux so that you can edit them separately, so yes, it offers more control in case you'd like to edit other things encoded in the video, say subtitles.

See this link for options.

Thank you, gentlemen.

I'd be a bit upset if a Sony Cybershot was still my primary camera, but I've moved on to a nice Canon S3, and have had no problems whatsoever in iMovie, as Canon's protocol is obviously not muxed a/v.

I'm good. Thanks again.

Simple way to use your muxed footage

The best way iv found so far to edit your muxed footage from a cybershot is to download and install visualhub -> http://www.techspansion.com/visualhub/ then drop your quicktime file onto the visualhub app select apple tv option and start it converting, your file will come out as an .m4v or mp4(cant remember exactly) now delete the .mpg file you started with, next open your new .m4v up in quicktime, select File from the menu bar an hit save as... name it and hit enter you will now have a .mov file demuxed an ready to edit in imovie.

Precisely what I ended up doing, but using iSquint.