The following table lists some common file formats and software which will handle them (though it may not be the only software which can be used). 

 

Compressed and encoded files

File extension  Definition How to process 
.au Sound format for Unix. Files are downloaded then played locally. Supports 8-bit sound only. Playable with LiveAudio plug-in which comes with Netscape Navigator 3.0 and higher. Internet Explorer 3.0+ supports .au MIME type
.mid, .midi

Actually a music definition language and communications protocol rather than a format, MIDI (Musical Instrument Digital Interface) contains instructions to perform particular commands

LiveAudio plug-in for Netscape. Automatically playable with sound-enabled versions of Internet Explorer or with Media Player.  Also Crescendo!, Yamaha's MIDPLUG. 

 

.mpeg
.mpg
(Motion Picture Experts Group). Widely used standard for digital compression of moving images. Files are played locally. MPEG viewers such as MPEGPlay, mtv-1.0, mtvp-sdk, QuickTime MPEG extension, HyperMPEG Player, XingMPEG Player (Windows), Sparkle (Mac).
.MP3 MPEG Audio Layer 3. Advanced compression technique for small near-CD-quality audio files  Windows Media Player, Sonique.
.qt3 QuickTime 3 - advanced compression format for video, audio, MIDI, animation, 3D, etc. Playable with QuickTime players.
.ra, .rm, .ram Real Audio, pioneering format for streaming audio on the Web optimized for low-to-medium speed connections.  RealPlayer, Windows Media Player
. wav Windows sound format Playable with LiveAudio plug-in which comes with Netscape Navigator 3.0 and higher. Playable in Internet Explorer 3.0. Also with Windows Media Player (included with Windows 98).