Audio

My daughter asked me recently to convert an audio file that a classmate of hers had created with an Ipad. It was a recording of a class. I looked around for converters and was pointed to Audacity, but it didn't work (it asked me to upload it as raw data, but once uploaded there was no reproducible audio). Other solutions such as "sox" where failing saying that it could not decode the source.

Reading further I seem to have understood that there is still no codec for Linux. I also looked to some free solutions in Windows and I found some, tried one and was also failing.