After upgrading to Fedora22 last week, I've had to sand down a few rough corners. One of them which has cropped up was that some of the tracks on Soundcloud just would not play while I was in Firefox. I thought it was likely because user-generated content is often prone to take-downs, spurious or not, and just kinda shrugged it off. But after trying to play a few particularly popular tracks from confirmed accounts, I decided something must be amiss. I popped open the code inspector, enabled the console, and right off the bat was greeted with a clever recruiting message from Soundcloud:

"You like to look under the hood? Why not help us build the engine? http://soundcloud.com/jobs"

Thereafter, I would get "Media resource could not be decoded" error messages followed by long strings representing the tracks.

Through some search-engine-foo, I was able to dig up this ticket: https://bugzilla.mozilla.org/show_bug.cgi?id=964032. In it, it is explained that there was likely an issue with codecs not being installed, with Ubuntu specific instructions. After originally enabling the RPM Fusion repos, I was able to search for and install gstreamer1-libav codec, restart Firefox, and play the broken tracks.