[MPlayer-users] decoding ogg theora with ffmpeg and not libtheora

[bond]

i recently tried decoding ogg theora files with mplayer with the ffmpeg
theora/vp3 decoder and not libtheora, but without success
i get the message that ffmpeg's decoder cant be used and than it falls back
to libtheora for decoding

i tried the following commandline:
mplayer -vfm ffmpeg theora.ogg

any idea whats wrong or how i can get it to work?