Engineering:Dolby Vision

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Short description: Set of technologies by Dolby Laboratories
Dolby Vision
Inception2014

Dolby Vision is a set of technologies developed by Dolby Laboratories for high dynamic range (HDR) video.[1][2][3] It covers content creation, distribution, and playback.[1][4][5][6] It includes dynamic metadata that define the aspect ratio and adjust the picture based on a display's capabilities on a per-shot or even per-frame basis, optimizing the presentation.

Dolby Vision was introduced in 2014,[1][7] making it the first available HDR format. HDR10+ is a competitor HDR format that also uses dynamic metadata.[8]

Dolby Vision IQ is an update designed to optimize Dolby Vision content according to the ambient light.[9]

Dolby Cinema uses Dolby Vision too, though because of the use of 2.6 gamma and thus 48 nits in SDR cinemas, the 108 nits used in Dolby Cinema is already HDR.[10]

Description

Dolby Vision allows for a maximum resolution of 8K, up to 12-bit color depth, maximum peak brightness of 10,000 nits.[11] However, according to the Dolby Vision white paper, as of 2018 professional reference monitors, such as the Dolby Vision HDR reference monitor, are currently limited to 4,000 nits of peak brightness.[12]

Dolby Vision includes the PQ transfer function, a wide-gamut color space (ITU-R Rec. BT.2020 in YCBCR or IPTPQc2), up to 8K resolution, and for some profiles (FEL) up to 12-bit. It can encode mastering display colorimetry information using static metadata (SMPTE ST 2086) and also provide dynamic metadata (SMPTE ST 2094-10, Dolby format) for each scene or frame.[13]

This dynamic metadata allows adjusting of the image on a scene-by-scene or even frame-by-frame basis.[14] These adjustments, called "trims" in Dolby's support documents, include parameters such as Lift, Gamma, Gain, Saturation, Chroma Weight, and so on. Each set of trims are specific to their respective target displays defined by nits and colorspace. Image aspect ratios can also be defined on a per-shot basis.[15]

Technical details

The Dolby Vision format is capable of representing videos with a peak brightness up to 10,000 cd/m2 and a color gamut up to Rec. 2020.[16] Current displays cannot reproduce the full Dolby Vision brightness and gamut capability. There are no brightness and color gamut capability requirements for consumer displays. When the consumer display has lower color volume than the mastering display, the content is adjusted to the consumer display capability based on the dynamic metadata.

Dolby Vision mastering displays require:[17]

  • EOTF: PQ
  • Peak brightness: at least 1,000 cd/m2
  • Black level: at most 0.005 cd/m2
  • Contrast ratio: at least 200,000:1
  • Color gamut: at least 99% of P3

Metadata

Dolby Vision metadata include:[15]

  • L0 (static): Mastering and target display characteristics
  • L1 (dynamic): Automatically generated
  • L2 trims (dynamic): Manually generated per frame or per scene
  • L3 trims (dynamic): Manually generated per frame or per scene (since CMv4.0)
  • L8 trims (dynamic): Manually generated per frame or per scene (since CMv4.0) (equivalent of L2 trims)
  • L5: Timeline aspect ratio description
  • L6 (static and optional): MaxCLL and MaxFALL (required for HDR10)
  • L9 (dynamic): Mastering display color primaries (since CMv4.0)

Dolby Vision 4.0 introduces new secondary trims for hue and saturation adjustment.[18]

Profiles

Dolby Vision profiles[19][20]
Profile Codec BL:EL resolution Backward compatibility
4 10-bit HEVC 1:1/4 SDR
5 10-bit HEVC No enhancement layer None (It uses proprietary IPTPQc2)
7 10-bit HEVC 1:1/4 for UHD

1:1 for FHD

Ultra HD Blu-ray
8 10-bit HEVC No enhancement layer HDR10 or SDR or HLG
9 8-bit AVC High or High Progressive Profile SDR
10 10-bit AV1 None or HDR10 or SDR or HLG
20 10bit MV-HEVC for 3D or HEVC for 2D None (It uses proprietary IPTPQc2)
Profiles not supported for new applications[19][20]
Profile Codec BL:EL resolution Backward compatibility
0 AVC 1:1/4 SDR
1 AVC 1:1 None
2 8-bit HEVC 1:1/4 SDR
3 8-bit HEVC 1:1 None
6 10-bit HEVC 1:1/4 HDR10
8 10-bit HEVC No enhancement layer

Dual layer

Some Dolby Vision profiles are dual layer (for example: the profile 7 used for Ultra HD Blu-ray).[20] The base layer (BL) and the enhancement layer (EL) are combined to produce a 12-bit video stream.[4]

The enhancement layer can be full enhancement layer (FEL) or minimum enhancement layer (MEL).[20]

File formats

License

Dolby Vision is a proprietary solution by Dolby.[26]

In 2021, compatible color grading systems can create Dolby Vision automatic metadata with no additional cost for content creators.[26] A $2,500 annual license is required to activate the trims allowing content creators to manually adjust the video.[26] OEM and manufacturer of a grading, mastering, editorial, or other professional application or device need to apply for a license.[26]

Dolby SVP of Business Giles Baker has stated that the royalty cost for Dolby Vision is less than $3 per TV.[27][28][29]

Libplacebo (as part of VideoLAN project) implemented support for Dolby Vision profile 5's IPTPQc2 color space, MMR and reshaping, yet no support of dynamic metadata and NLQ yet.[30]

MPC Video Renderer implemented partial support for Dolby Vision (Profiles 5, 8.1, 8.4 are supported).[31]

Adoption

Hardware

  • Monitors:
    • ASUS

Content distribution

Software

  • Color grading:[26]
  • Encoder:
    • x265: Profile 5, profile 8.1 and profile 8.2 (since version 3.0)[43]
  • Media player:

Notes

  1. ↑ iPhone 8/8 Plus, XR, 11, and SE (2nd generation) can play Dolby Vision content despite not having an HDR-ready display, done by down-converting the HDR content to fit the display while still having some enhancements to dynamic range, contrast, and wide color gamut compared to standard content.[34]

References

  1. ↑ 1.0 1.1 1.2 "Dolby Vision Whitepaper - An introduction to Dolby Vision". Dolby. https://professional.dolby.com/siteassets/pdfs/dolby-vision-whitepaper_an-introduction-to-dolby-vision_0916.pdf. 
  2. ↑ "Understanding HDR10 and Dolby Vision". https://www.gsmarena.com/understanding_hdr10_and_dolby_vision-news-46151.php. 
  3. ↑ "The state of HDR video mid-2017". https://www.flatpanelshd.com/focus.php?subaction=showfull&id=1505390780. 
  4. ↑ 4.0 4.1 "Dolby Vision Whitepaper". Dolby Laboratories. http://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-white-paper.pdf. 
  5. ↑ "Dolby Vision for Content Creators". https://professional.dolby.com/content-creation/dolby-vision-for-content-creators/5. 
  6. ↑ 6.0 6.1 6.2 "Create in Dolby Vision, Now on the Full iPhone 12 Lineup". https://professional.dolby.com/content-creation/create-in-dolby-vision-on-iphone-12/. 
  7. ↑ "CES 2014: Dolby Vision promises a brighter future for TV, Netflix and Xbox Video on board". 6 January 2014. https://www.expertreviews.co.uk/go/27453. 
  8. ↑ "HDR Terminology Demystified". 23 August 2019. https://www.flatpanelshd.com/focus.php?subaction=showfull&id=1566562819. 
  9. ↑ Roberts, Becky; February 2021, Tom Parsons 21 (21 February 2021). "Dolby Vision IQ: Everything You Need to Know". https://www.whathifi.com/advice/dolby-vision-iq-everything-you-need-to-know. 
  10. ↑ "Dolby Vision cinema targets & trims FAQs". https://professionalsupport.dolby.com/s/article/Dolby-Vision-cinema-targets-trims-FAQs?language=en_US#Tools_support. 
  11. ↑ "Dolby Vision for Content Creators". https://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-profiles-levels.pdf. 
  12. ↑ Dolby Laboratories. "Dolby Vision Whitepaper". http://www.dolby.com/us/en/technologies/dolby-vision/dolby-vision-white-paper.pdf. 
  13. ↑ "SMPTE ST 2094 and Dynamic Metadata". Society of Motion Picture and Television Engineers. https://www.smpte.org/sites/default/files/2017-01-12-ST-2094-Borg-V2-Handout.pdf. 
  14. ↑ "HDR TV: What it is and why your next TV should have it". Designtechnica Corporation. 19 December 2020. https://www.digitaltrends.com/home-theater/what-is-hdr-tv/. 
  15. ↑ 15.0 15.1 "Dolby Vision Metadata Levels". Dolby. 23 January 2021. https://professionalsupport.dolby.com/s/article/Dolby-Vision-Metadata-Levels?language=en_US. 
  16. ↑ "What Is Dolby Vision? Dolby's Own HDR Tech Explained". 13 October 2020. https://www.pocket-lint.com/tv/news/dolby/139947-what-is-dolby-vision-dolby-s-very-own-hdr-tv-tech-explained. 
  17. ↑ "Dolby Vision for Content Creators - Workflows". https://professional.dolby.com/content-creation/dolby-vision-for-content-creators/2. 
  18. ↑ "Dolby Vision and Independent Filmmaking". https://www.mysterybox.us/blog/2019/3/18/dolby-vision-and-independent-filmmaking-e75yg. 
  19. ↑ 19.0 19.1 "Dolby Vision Profiles and Levels Version 1.4 - Specification". Dolby. https://professionalsupport.dolby.com/s/article/What-is-Dolby-Vision-Profile?language=en_US. [|permanent dead link|dead link}}]
  20. ↑ 20.0 20.1 20.2 20.3 "What Are Dolby Vision Profiles?". Dolby. 7 December 2023. https://professionalsupport.dolby.com/s/article/What-is-Dolby-Vision-Profile?language=en_US. 
  21. ↑ "Dolby Vision Streams within the ISO Base Media File Format v2.0". Dolby Laboratories. 12 December 2017. https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolby_vision_bitstreams_within_the_iso_base_media_file_format_dec2017.pdf. 
  22. ↑ 22.0 22.1 22.2 22.3 "How to Signal Dolby Vision in ISOBMFF Format (AKA mp4 Container)?". Dolby. 16 November 2020. https://professionalsupport.dolby.com/s/article/How-to-signal-Dolby-Vision-in-ISOBMFF-format-AKA-mp4-container?language=en_US. 
  23. ↑ "Dolby Vision Streams within the HTTP Live Streaming format v2.0". Dolby Laboratories. 13 November 2018. https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolby-vision-streams-within-the-http-live-streaming-format-v2.0-13-november-2018.pdf. 
  24. ↑ "Dolby Vision Streams within the MPEG-2 Transport Stream Format v1.2". Dolby Laboratories. https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolby-vision-bitstreams-in-mpeg-2-transport-stream-multiplex-v1.2.pdf. 
  25. ↑ "Dolby Vision Streams within the MPEG-DASH format v2.0". Dolby Laboratories. 13 November 2018. https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolbyvisioninmpegdashspecification_v2_0_public_20190107.pdf. 
  26. ↑ 26.0 26.1 26.2 26.3 26.4 "Dolby Vision for Content Creators - Solutions". https://professional.dolby.com/content-creation/dolby-vision-for-content-creators/3. 
  27. ↑ Tim Moynihan (20 January 2016). "What you need to know before buying an HDR TV". Wired. https://www.wired.com/2016/01/what-is-hdr-tv/. Retrieved 26 January 2017. 
  28. ↑ Giles Baker (20 September 2016). "Dolby Vision and HDR10: What Format War?". LinkedIn. https://www.linkedin.com/pulse/dolby-vision-hdr10-what-format-war-giles-baker. 
  29. ↑ Neikirk, Lee (9 September 2016). "Dolby Says the "HDR Format War" Doesn't Exist". http://televisions.reviewed.com/features/dolby-says-the-hdr-format-war-doesnt-exist. 
  30. ↑ "colorspace: add support for Dolby Vision (!207) · Merge requests · VideoLAN / libplacebo". 29 November 2021. https://code.videolan.org/videolan/libplacebo/-/merge_requests/207. 
  31. ↑ "Release MPC Video Renderer 0.6.9.2117 · Aleksoid1978/VideoRenderer". August 7, 2023. https://github.com/Aleksoid1978/VideoRenderer/releases/tag/0.6.9. 
  32. ↑ "TV Database". https://www.flatpanelshd.com/TVdatabase.php. 
  33. ↑ Cruz, Claudia. "LG G6 Is the First Phone to Debut Dolby Vision HDR". https://www.cnet.com/news/lg-g6-becomes-first-smartphone-to-debut-dolby-vision-hdr/. 
  34. ↑ Wong, Raymond (22 September 2017). "The iPhone 8 and 8 Plus Don't Really Support True HDR Video Playback". https://mashable.com/2017/09/22/netflix-hdr-not-real-iphone-8-plus/. 
  35. ↑ "Xiaomi Mi 11 Ultra review". https://www.gsmarena.com/xiaomi_mi_11_ultra-review-2259.php. 
  36. ↑ "Xiaomi Mi 11 Pro debuts with Snapdragon 888 and Samsung's GN2 50MP sensor". https://www.gsmarena.com/xiaomi_mi_11_pro_debuts_in_china_with_sd_888_and_samsungs_gn2_50mp_sensor-news-48420.php. 
  37. ↑ "Xbox Support". https://support.xbox.com/en-US/help/hardware-network/display-sound/dolby-vision. 
  38. ↑ Sarkar, Samit (28 September 2021). "Dolby Vision Gaming Goes Live on Xbox Series X". https://www.polygon.com/22697096/dolby-vision-xbox-series-x-s-hdr-games. 
  39. ↑ "Ultra HD Blu-ray: Everything You Need to Know". 26 September 2019. https://www.digitaltrends.com/home-theater/ultra-hd-blu-ray-specs-dates-and-titles/. 
  40. ↑ "Cinema-grade video for all: Vimeo supports Dolby Vision for Apple devices". Vimeo. 10 September 2021. https://vimeo.com/blog/post/dolby-vision-support-apple-devices/. 
  41. ↑ "Where to watch content in Dolby Vision". https://www.dolby.com/en-gb/experience/home-entertainment/where-to-watch-content-in-dolby-vision/. 
  42. ↑ "【全球首家】杜比视界用户投稿功能上线啦！" (in Chinese). 18 August 2021. http://www.bilibili.com/read/cv12741112. 
  43. ↑ "Release Notes — x265 documentation". https://x265.readthedocs.io/en/latest/releasenotes.html. 
  44. ↑ 44.0 44.1 "Changelogs for K-Lite Mega Codec Pack". 3 August 2023. https://codecguide.com/changelogs_mega.htm. 

External links



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