Arista is an easy-to-use multimedia transcoder for the GNOME desktop. It focuses on the goal of transcoding media, namely the devices you wish to play the media on. It is designed for use by people who are not familiar with audio and video encoding and want an easy way to get multimedia to their devices. It supports input from DVD and V4L devices as well as regular files.
Midi Converter for Mac is a small and simple utility designed mostly for musicians who compose music using their computer. However, it can be very useful for anyone who wants to convert MIDI music files to MP3 or other popular formats. It is around 10 times faster than the other competing programs, because it converts the files directly rather than having to record them first. The program is very easy to use, and a trial version is available. It also allows you to embed a player, and has a number of other features. It does not rely on your sound card with regards to the quality of the final output, so you can expect high and consistent quality, regardless of what sort of computer you are going to use it on.