If you're not able to find your audio clip in iTunes it's because iTunes thinks it's a movie file. Haven't figured out why this is the case.
SMART CONVERTER PRO 2 ACTIVATION MP4
Some mp4 files will not convert to audio-only. Smart Converter can't make a video compress with Sorenson Codec look better in MP4. Keep in mind that the final conversation is only as good as the source. (Not Smart Converter problem as Quicktime will have this same issue.) I have found ElMedia Player as a good converter in these cases. Apparently, there's a lot of masking between shots This means that you'll see some strange views in your final output. Some video screen capture files done in Snagit will not convert well. If you have a lot of files that need converting, then going pro is the way to go. Haven't upgrade to the Pro version because I don't have the need for all the features of going pro.
Useful when I just want the soundtrack and not have to watch the movie.
I also use Smart Converter to extract audio from MOV files. (Without Smart Converter I would have to wait for Quicktime to convert old Sorxxx codec videos) It's a quick way to once again access old media files. I like Smart Converter because It can easily convert classic media files - such as Real Media files to MP4.