You should get in to the habit of only importing PCM .wav files to Construct 2. I've just recently added a relevant article to the manual on the Import Audio dialog
which has relevant info.
The AAC encoder supports the .mp3 format, but the Ogg Vorbis encoder does not support it, so it only gets imported as AAC. The article I linked to also describes how .m4a is a backup to an .ogg file (so .oggs take priority) which is why you can't select just an .m4a in the event system.
Construct 2 could
decode MP3 and re-encode it to .ogg but this degrades quality, and encoders are complicated, difficult to deal with, and if used in commercial software like Construct 2 sometimes incurs some hefty fees for us, so we just totally avoid it. You should use your own audio encoding software to decode your MP3 to .wav if you must, but it's really best to just import PCM .wav files all the time for everything. I nearly took out the option to import formats like MP3 at all, but I thought we may as well leave it in if the encoder is capable.Ashley2011-12-02 01:12:49