How can I transcode an IMA4 ADPCM audio file recorded on the iPhone?

Question

For bandwidth reasons I would like to use Apple's implementation of the IMA4 format available for recording on the iPhone. This format is great for space, but it seems to be hard to find any programs that can transcode it into something like linear PCM or MP3. I've tried sox and Transcode to no avail. I need to be able to do this automatically and on a Linux server, so iTunes is out of the question.

Answer 1

IMA4 isn't a very complicated format, so you could write your own parser if you had to. Here's a post that has all the information you'd need...

http://www.wooji-juice.com/blog/iphone-openal-ima4-adpcm.html