Sustainability of Digital Formats: Planning for Library of Congress Collections

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Apple ProRes 422 High Quality

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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 High Quality
Description

Apple ProRes 422 HQ is the highest data-rate version of the ProRes 422 codecs, applying the least compression for the best imagery and the largest files. Apple literature states that Apple ProRes 422 HQ offers "visually lossless preservation of the highest-quality professional HD video that a single-link HD-SDI signal can carry."

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 220 Mbps target data rate for Apple ProRes 422 HQ would yield a one-hour file of about 97 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 The Civil Rights History Project in the American Folklife Center contains Apple ProRes 422 and Apple ProRes 422 HQ files.
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)

Excellent, many positive comments online. For example, the video specialist Gary Adcock states that ProRes 422 HQ provides nearly the same quality of uncompressed 10-bit 4:2:2 video but at about 1/5th the file size and throughput.

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 apch
From Multimedia wiki entry on ProRes but this is not listed on the fourCC.org webpage.

Notes Explanation of format description terms

General

According to Apple, camera formats that would be appropriate to convert to ProRes 422 HQ for editing include Sony HDCam SR, DVCPro HD, HDV, and AVC Intra. Some specialists caution against this. Larry Jordan, for example, states that unless the source file is "very carefully-lit, high-end video, such as RED, HDCAM, or HDCAM SR, the quality of your source image doesn’t equal the format."

History

Apple ProRes 422 HQ is one of the two original ProRes codecs (along with Apple Pro Res 422).


Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: Monday, 27-Feb-2017 09:55:15 EST