I've had success using the ogg encoder before as well set up like you hav it, but it doesn't work with every version of ffmpeg. That's been my major problem all along; I can optimize for mobile, or optimize for video, but it's hard to get everything optimized on the same setup. Using ffmpeg on 4.6 for the ogg transcoding causes playback problems on Android ans causes the tracks to only playback about 75% of the way through. The last time I tried setting up the ogg transcoder I couldn't get the wav output into the ogg transcoder. Seeing that you're using oggenc in your transcode string, rather than oggenc2, Iwould also assume that your not on a Windows platform??
Another interesting anomaly is that I can playback video on a standard 4.6 install and get index reporting and seeking on wtv files, but later versions of ffmpeg make better use of load distribution on multicore CPU's. I then tried using the 4.6 ffmpeg on version 4.5 and lost the indexing ability.
A lot of trial and error, but each setup should be customizable to meet a user's needs. For me, right now, using 4.5 with 3 different versions of ffmpeg doing different file type transcodings has produced the best all around solution. I know Sindre is working hard resolving many of these issues for the upcoming 4.7 release. may the programming gods smile upon him.
