Can I convert .m4a files directly to .wave format.
Converting MPEG-4 Audio Files directly to WAVE Sound Files (.m4a to .wave conversion) is certainly possible, and is doable using the appropriate software.
Try using, for instance, Helium Music Manager, which will allow you to transcode your MPEG-4 audio file (.m4a) to a WAVE sound file (.wave).
A music library management program
A multimedia converting tool for Windows