Inserting Media > Adding sound to a page > About audio file formats

About audio file formats

The following list describes the more common audio file formats along with some of the advantages and disadvantages of each for Web design.

.midi or .mid (Musical Instrument Digital Interface) format is for instrumental music. MIDI files are supported by many browsers and don't require a plugin. Although their sound quality is very good, it can vary depending on a visitor's sound card. A small MIDI file can provide a long sound clip. MIDI files cannot be recorded and must be synthesized on a computer with special hardware and software.

.wav (Waveform Extension) format files have good sound quality, are supported by many browsers, and don't require a plugin. You can record your own WAV files from a CD, tape, microphone, and so on. However, the large file size severely limits the length of sound clips that you can use on your Web pages.

.aif (Audio Interchange File Format, or AIFF) format, like WAV format, has good sound quality, can be played by most browsers, and don't require a plugin; you can also record AIFF files from a CD, tape, microphone, and so on. However, the large file size severely limits the length of sound clips that you can use on your Web pages.

.mp3 (Motion Picture Experts Group Audio, or MPEG-Audio Layer-3) format is a compressed format that makes sound files substantially smaller. The sound quality is very good: if an MP3 file is recorded and compressed properly, its quality can rival that of a CD. New technology lets you "stream" the file so that a visitor doesn't have to wait for the entire file to download before hearing it. However, the file size is larger than a Real Audio file, so a whole song could still take quite a while to download over a normal phone line connection. To play MP3 files, visitors must download and install a helper application or plugin such as QuickTime, Windows Media Player or RealPlayer.

.ra, .ram, .rpm, or Real Audio format has a very high degree of compression with smaller file sizes than MP3. Whole song files can be downloaded in a reasonable amount of time. Because the files can be "streamed" from a normal Web server, visitors can begin listening to the sound before the file has completely downloaded. The sound quality is poorer than that of MP3 files, but new players and encoders have improved quality considerably. Visitors must download and install the RealPlayer helper application or plugin in order to play these files.