NOTE: This Guide only applies to ImgBurn 22.214.171.124+ and is for burning a *proper* Audio CD (typically 80 minutes worth of audio) that's playable in any standalone CD player.
If you want to burn MP3 files for playback in an MP3 ready CD player, just add the files in Build mode and ignore this guide.
ImgBurn's ability to burn Audio CD's is currently based around the well known 'CUE' (as in 'BIN + CUE') image file format.
To burn music files (MP3 etc) you first need to create a CUE file.
ImgBurn relies on DirectShow / ACM for decoding your audio files.
As such, you'll need to have the appropriate filters installed for the types of files you'll be burning.
Support for MP3, PCM, WAV and WMA should be built into Windows - at least it is on XP / Vista / 7.
For other file types, try the following:
AAC - CoreAAC - http://www.free-codecs.com/download/CoreAAC_Directshow_filter.htm
AAC - ORBAN - http://www.orban.com/plugin/ or http://w