MIDIRenderer can use any popular audio codec for output files. It could be lossy MP3, WMA, OGG formats, lossless APE and FLAC, uncompressed WAV or even Adaptive Multi-Rate codec for mobile devices. You can select the desired format from the drop-down menu:
For advanced options click "Encoder Options" button. "Settings" window will appear.
Here you can choose encoding options that determine quality of the output files: sampling rate, mode (Stereo or Mono), and bitrate. Lower bitrate gives you smaller files size, but the worse will be quality. No sense what output mode you will use because MIDI files always in Mono format.
By default, MIDIRenderer will use 44100Hz sampling rate during MIDI to MP3 conversion.