Does Amazing Audio Player support m4a audio format?
From version 3.5, Amazing Audio Player has added the support for m4a audio format. In the application, step 1, Add Audios dialog, you can click the first button "Add audios" and select an m4a file.
After you add the m4a file to the dialog, you need to find the length (in seconds) of your audio file and enter it to the "Duration (seconds)" input box.
You can play your m4a file with an audio player on your computer and get its length. For example, if the length is 2 minutes and 30 seconds, that's, 2:30, you need to enter 150 to the "Duration (seconds)" input box, that's, 2 * 60 + 30 seconds.