Sustainability of Digital Formats
 Planning for Library of Congress Collections

Format Description Categories >> Browse Alphabetical List>> Back

Identification and description

Full name	RealAudio, Lossless Codec
Description	Audio compression codec recommended by RealMedia for use by "professional and archiving services." The codec creator report that the compression algorithm generally cuts` file sizes in half.
Production phase	Generally a middle-state format, suitable for use in asset management and archiving.
Relationship to other formats
Used by	RealAudio_10, RealAudio, Version 10

Local use

LC experience or existing holdings	See RealAudio_10
LC preference	See RealAudio_10

Sustainability factors

Disclosure	See RealAudio_10
Documentation	See RealAudio_10
Adoption	See RealAudio_10
Licensing and patents	See RealAudio_10
Transparency	See RealAudio_10
Self-documentation	See RealAudio_10
External dependencies	See RealAudio_10
Technical protection considerations	See RealAudio_10

Quality and functionality factors

Sound
Normal rendering	Good support
Fidelity (high audio resolution)	Excellent, although the application may be limited to CD-quality source material (44.1 kHz sampling, 16-bit words).
Multiple channels	Not investigated

File type signifiers

Tag	Value	Note
Filename extension	Not applicable.	See RealAudio_10
Internet Media Type	Not applicable.	See RealAudio_10
Magic numbers	Not applicable.	See RealAudio_10
Microsoft FOURCC	ralf	For the lossless codec (RealAudio 10), this fourcc code will appear in the RealAudio_10 file wrapper.

Notes

General
History

Format specifications

• See Disclosure under Sustainability factors.

Useful references