Xiph has specified that .oga be used as the extension on Ogg files that contain Vorbis audio. The SoundJuicer CD ripper in the 8.10 release of Ubuntu uses a gstreamer pipeline to rip CD’s to vorbis format. The default pipeline has been updated to create files with an extension of .oga in accordance with the Xiph guidelines.
Firefly, as it is provided by Ubuntu (version svn-1696) does not index these files. Adding .oga to the extensions element in the configuration file does not seem to fix the problem.
extensions = .mp3,.m4a,.m4p,.ogg,.oga,.flac,.mpc
My understanding is the default configuration transcodes all formats to wav. The transcoding part should remain the same as the file is an Ogg file with a Vorbis stream. So this may be a problem on the indexing side. Perhaps .oga is not mapped to the process used to grab metadata from .ogg files. If this is the case, my feature request is to have that mapping added.