Different types of audio services require different formats for the audio information and different technologies to reproduce audio. The Multimedia extensions offer the following types of audio services:
Waveform audio services provide playback and recording support for digital audio hardware. Waveform audio is useful for reproducing non-musical audio material such as sound effects and voice-over narration. Waveform audio has moderate storage space and data transfer rate requirements—as low as 11K per second of audio.
MIDI audio services provide support for MIDI file and MIDI event playback through internal or external synthesizers and MIDI event recording. MIDI audio is useful with music-related applications such as music composition and MIDI sequencer programs. Because it requires less storage space and a lower data transfer rate than waveform audio, you might want to use MIDI audio services to provide introductory and background music in your applications.
Compact disc audio services provide support for playback of Red Book audio information on compact discs with the CD-ROM drive on multimedia computers. Compact disc audio offers the highest quality reproduction of musical material, but has the highest storage space requirements—176K per second of audio. You cannot read from the CD-ROM drive while playing compact disc audio.