Sustainability of Digital Formats
 Planning for Library of Congress Collections

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Identification and description

Full name	AVI (Audio Video Interleaved), Cinepak Video Codec
Description	File format that wraps a Cinepak video bitstream with other data chunks, e.g., audio, in an AVI wrapper. Multiple versions of Cinepak exist, including SuperMac, Radius, and Compression Technologies; this document does not distinguish between them.
Production phase	Used as a middle-state format (often used as the video source when producing lower-resolution streaming versions); also used as a final-state format for enduser delivery.
Relationship to other formats
Subtype of	AVI,
Contains	Cinepak, video codec
May contain	WAVE, audio (interleaved with video)
May contain	MP3_CBR, (constant bit rate) audio (interleaved with video)

Local use

LC experience or existing holdings
LC preference	See AVI

Sustainability factors

Disclosure	See AVI and Cinepak
Documentation	See AVI and Cinepak
Adoption	AVI is widely adopted for video production and filemaking; commentator John McGowan writes, "Cinepak is the most widely used Video for Windows codecs."
Licensing and patents	See AVI and Cinepak
Transparency	See Cinepak
Self-documentation	See AVI
External dependencies	See AVI
Technical protection considerations	See AVI

Quality and functionality factors

Moving Image
Normal rendering	Good support.
Clarity (high image resolution)	Moderate to good, given that this is a format typically used for compression and does not support interlaced video. Outcome will depend on the type and extent of compression, and the encoder used. High resolution work is limited in the Windows environment due to file size limits (2 GB with FAT 16 technology; theoretical 8 GB with later technologies).
Functionality beyond normal rendering	See AVI

File type signifiers

Tag	Value	Note
Filename extension	avi
Internet Media Type	See related format.	See AVI.
Magic numbers	See related format.	See AVI.
Microsoft FOURCC	CVID	See the list of FOURCC codes. FOURCC codes are no longer managed by Microsoft, which has developed a new mechanism for identifying rich media types in general.

Notes

General
History

Format specifications

• See Disclosure under Sustainability factors.

Useful references

URLs

• John McGowan's AVI Overview (http://www.jmcgowan.com/avi.html).
• John McGowan's AVI Audio and Video Codecs (http://www.jmcgowan.com/avicodecs.html).
• List of FOURCC codes (http://www.fourcc.org/codecs.php). FOURCC codes were originally managed in a registry by Microsoft, but have been superseded by a more general mechanism to identify media types.