Sustainability of Digital Formats: Planning for Library of Congress Collections
Sustainability of Digital Formats: Planning for Library of Congress Collections |
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | Apple ProRes 422 High Quality |
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| 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 |
| Used by | IMF_Package, Interoperable Master Format (IMF). As of December 2023, Apple ProRes 422 HQ is the video track requirement for IMPs for the BBC iPlayer to conform to RDD 59-1:2022 - SMPTE Registered Disclosure Doc - Interoperable Master Format — Application DPP (ProRes). |
| 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. |
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| LC preference | The Library of Congress Recommended Formats Statement (RFS) lists Apple ProRes 4444, 4444 XQ and 422 HQ in a QuickTime wrapper as a Preferred format for Video - File-Based and Physical Media. |
| Disclosure | See Apple_ProRes_422_Codec_Family |
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| Documentation | See Apple_ProRes_422_Codec_Family |
| Adoption |
Netflix added ProRes 422 HQ "as an acceptable delivery format for 2K, UHD, and 4K resolutions" for licensed content (not original content) starting in July 2019 with Version 9.0 of Netflix Licensed Content Delivery Specification and Operators Manual. YouTube includes ProRes 422 HQ as an upload option for specific types of content: TV - Library/Back Catalog TV, Next Day TV; Movies - New Release movies delivered more than 2 weeks prior to avail start date and Library/Back Catalog movies. New release movies delivered less than 2 weeks prior to avail start date are not supported by ProRes 422 HQ "due to the additional processing time required to process large ProRes files". |
| Licensing and patents | See Apple_ProRes_422_Codec_Family |
| Transparency | See Apple_ProRes_422_Codec_Family |
| Self-documentation |
See QuickTime Accessibility Features Typically, accessibility features such as captions and subtitles are carried in containers and wrappers, not in encoded video data. QuickTime is a common wrapper for ProRes family codecs, though others may be used. See QuickTime for web accessibility information. See W3C's Making Audio and Video Media Accessible for more general information about accessible sound and moving image media. |
| External dependencies | See Apple_ProRes_422_Codec_Family |
| Technical protection considerations | See Apple_ProRes_422_Codec_Family |
| Moving Image | |
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| 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 |
| Tag | Value | Note |
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| Filename extension | See note. | See Apple ProRes 422 Codec Family |
| FOURCC | Big endian: apch Little endian: hcpa |
FOURCC code used to indicate ProRes 442 HQ in the QuickTime container according to Multimedia Wiki. |
| Pronom PUID | See related format. | See Apple ProRes 422 Codec Family |
| Wikidata Title ID | See related format. | See Apple ProRes 422 Codec Family |
| 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." |
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| History |
Apple ProRes 422 HQ is one of the two original ProRes codecs (along with Apple Pro Res 422). |
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