SDK FFMPEG

Hello all, been working on trancoding a live stream with some success with ffmpeg. I came across the following in the sdk and was wondering exactly what the -vpre roku was. When I attempted to run this I got an error file for preset ‘roku’ not found. Is this a file already created with parameters for ffmpeg that is somewhere that needs to be downloaded?

% ffmpeg -i -f mpegts -acodec libfaac -vcodec libx264
-vpre roku -crf 15 -threads 0 ~/OneTransportStreamFile3200.ts

Thanks