Do M4A Files Work with Smart Podcast Player?
As of now, M4A files are not officially supported.
The Smart Podcast Player (the full player) only currently supports feeds that use the MP3 file format. If your episodes have been encoded in M4A format, you may find that the feed doesn't load in the Smart Podcast Player.
The Smart Track Player may work with M4A files, but we can't guarantee that it will. Your best bet is to make sure that all your episodes have been encoded as MP3 files.