Sometimes when using winff (via ffmpeg) http://winff.org/html_new/ to convert mp3s to ogg you get an annoying error message – Unknown encoder ‘vorbis’.

To solve this problem try the following.

Open up winff, and from the main menu select Edit->Presets. Select Audio type (not a video we are converting), and OGG sub category. In preset command line parameters replace -acodec vorbis with instead -acodec libvorbis (note lib in libvorbis). Then CLICK ADD/UPDATE BUTTON (important, it won’t work making preset changes if you just save it), then press Save Button.

Screenshot-Edit Presets

(click for larger image)

Works for me under linux.