It has no issues with mp4, webm, and 3gpp, other than this gem is not smart enough to know if the uploaded file is either mp4 or webm and will transcode a mp4 to a mp4 for example. But it chokes on flv.
The gem is a wrapper for ffmpeg/libav. If FLV files are not being transcoded then you might need to recompile ffmpeg/libav with FLV support. Please check ffmpeg/libav documentation.
There seems to be no docs that I can find.
It has no issues with mp4, webm, and 3gpp, other than this gem is not smart enough to know if the uploaded file is either mp4 or webm and will transcode a mp4 to a mp4 for example. But it chokes on flv.