Thanks for the link, I only have a little linux experience myself, I don't know how to compile ffmpeg on my unraid. I wish I could compile 0.8.1 version.
I'm using the following custom line in subsonic: It works really good
ffmpeg -ss %o -i %s -async 1 -b %bk -s %wx%h -ar 44100 -ac 2 -v 0 -threads 0 -vcodec libx264 -fpre /var/subsonic/data/transcode/libx264-fastfirstpass.ffpreset -f flv -