AVI size inflates when I add new audio

[yarnzift]

I have a 3 minute, 170 MB AVI file from my video camera (640 x 480). The sounds quality is bad, so I recorded the sound separately. I used iMovie to remove the video sound and add the new sound file (3 MB). When I export from imovie the AVI file is very large (4 GB). If I export a compressed version, the quality is poor, and the size is still 1 GB. I've tried converting the big file using bitplayer, but I cannot recover anything close to the quality / size of the original.

Can someone suggest a better way to do this so that I do not add so much to the file size? Thanks for any advice.

[Baldrick]

What codec have you tried?

Or you could use a multiplexer to add the old video with the new audio without any video converting. But I don't know any such tool for mac osx though.

[yarnzift]

I've tried exporting as "QuickTime" and "AVI" using H.264, DV-PAL and MPEG-4 video compression (I hope that answers the codec question). I think that this iMovie HD software is designed for higher resolution input, so when it imports my video it converts it to a bulky "isight" format.

[yarnzift]

Ok, I've found a workable solution. There is a "video edit" section in the Canon ImageBrowser software that came with my camera (PowerShot SD890). I can add a single audio track and turn down volume of original audio. Also I can do some basic titling etc. Audio track can't be moved in time to sync it, so I had to tweak it in garage band through a two step process (garage band won't open the AVI from the camera, so had to convert it first with bitplayer then open it in garage band to visually sync the audio tracks [easy part] and export audio. Convoluted process, but at least it works for now.