For years, PCO Services could transpose mp3 audio files you uploaded so your team members could listen to them in the key they'd be playing or singing them in. The problem is most people's music is in m4a format. You would upload an m4a, it wouldn't give you the option to transpose, and so you never knew it existed.
Now, in addition to mp3 files, we now support transposing m4a and aac files, so there's no need to convert files to mp3 before uploading them. Hooray!
Copyrights & Licensing
Remember that in order to share audio files you did not create, you must have a license. The good news is that it's easier and more affordable than ever to obtain those licenses. See our lesson on Copyright Concerns for information about CCLI's Rehearsal License and other ways to obtain licensing.