I had issues following the steps and recompiling AM and not having mmal show up. Which is fine, I'll fuss around with it and figure it out, but knowing I don't have to chase after ffmpeg like that as the possible cause of the issue cuts a HUGE amount of time out of stuff (especially since ffmpeg easily takes the longest to compile). So thanks a ton for clearing that up for me, hopefully I can get this working now.
edit: actually double checking, ffmpeg is definitely the problem. D.V.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_mmal ) doesn't show up and I got library misconfigurations a mile long. Clearly something is installed somewhere that's fucking things up and I just gotta try and figure it out I guess.