Sustainability of Digital Formats: Planning for Library of Congress Collections

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Apple ProRes 422 Proxy

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Apple ProRes 422 Proxy
Description

Apple ProRes 422 Proxy is the fourth-highest data-rate version of the ProRes 422 codecs. Apple literature highlights the value of Apple ProRes 422 Proxy in support of post-production work, stating that it is "intended for use in offline workflows that require low data rates but full-resolution video."

In order to compare the members of the ProRes 422 family, this Web site uses 10-bit picture data with an HD (1920x1080) frame size and a frame rate of 29.97 fps. Uncompressed, this yields about 560 GB per hour. Although the variable bit rate for ProRes means that results will vary, specialists report that the 45 Mbps target data rate for Apple ProRes 422 Proxy would yield a one-hour file of about 20 GB.

See the Apple ProRes 422 Codec Family for a general description of the shared technical characteristics as well as history of the format.

Production phase Production (initial state) and post production (middle state).
Relationship to other formats
    Subtype of Apple_ProRes_422_Codec_Family, Apple ProRes 422 Codec Family

Local use Explanation of format description terms

LC experience or existing holdings  
LC preference  

Sustainability factors Explanation of format description terms

Disclosure See Apple_ProRes_422_Codec_Family
    Documentation See Apple_ProRes_422_Codec_Family
Adoption See Apple_ProRes_422_Codec_Family
    Licensing and patents See Apple_ProRes_422_Codec_Family
Transparency See Apple_ProRes_422_Codec_Family
Self-documentation See Apple_ProRes_422_Codec_Family
External dependencies See Apple_ProRes_422_Codec_Family
Technical protection considerations See Apple_ProRes_422_Codec_Family

Quality and functionality factors Explanation of format description terms

Moving Image
Normal rendering See Apple ProRes 422 Codec Family
Clarity (high image resolution) Good. Primarily used as a high quality edit or viewing proxy; may be used as a final state deliverable where small file sizes are required.
Functionality beyond normal rendering See Apple ProRes 422 Codec Family

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension See note.  See Apple_ProRes_422_Codec_Family
Microsoft FOURCC apco
From Matroska section on ProRes but this is not listed on the fourCC.org webpage.

Notes Explanation of format description terms

General See Apple ProRes 422 Codec Family
History

Apple ProRes 422 Proxy is so named because it serves as the high-quality edit proxy for Final Cut Server.


Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: 02/27/2017