m4b not working in 4.7 (3106)

[FalseTetrabyte]

I had it working in my last install of Subsonic, but for the life of me, I Cannot get those exact same files to work in this installation now.

I've made sure that the line for mp3 audio in transcoding has m4b in the "convert from" line, as well as added it to General under Music (tried video too just because) and rescanned the library after every change.

What am I missing? An FAQ page on the forums states that m4b is supported, and the files have worked in the past. What gives?