MIDI (Musical Instrument Digital Interface):
A MIDI file contains synthesized music. MIDI is a great choice for web, because the files are small in size. MIDI files are typically created using computer-based sequencing software or sometimes a hardware-based MIDI instrument or workstation, which organizes MIDI messages into one or more parallel “tracks” for independent recording and editing.
WAV (as in WAVe):
A WAV file provide very good quality sampled sound, but is usable almost exclusively on Windows computers. It is one of the first audio-standards. WAV files are virtually of the same quality as data on audio-CDs and therefore offer the best quality. At the same time these files are very large (10 MB / min.), that’s why they are unsuitable for everyday exchange via the internet.
MP3 (MPEG 1 Layer III Audio):
MP3 was introduced in 1992 and until today it is the most successful audio-standard since WAV. Using MP3-compression PC-users can compress an ordinary music-CD to one tenth of it’s original size – thus 12 hours of music could be stored on a recordable CD that on the other hand could be played by a MP3-CD-player or an ordinary PC.
WMA (Windows Media Audio)
WMA files are almost of CD-quality with just a third of the source-file’s size. Like MP3 WMA is almost predestined for the internet by offering streaming capabilities both with WMA and WMV (Windows Media Video).
AIFF (Audio Interchange File Format)
This format was developed by Apple for storing high-quality sampled sound and musical instrument info.AIFF file contains a recorded sound sample, which may be music or a sound effect. The specification is very long and allows for lots of different features.