Re: Principles of HDR in chrome

Hi Fredrik,

Great write-up.

A few comments:
The broadcast industry has not come to an agreement of how to map SDR white to HDR in media
Some big studios map SDR white to PQ 300 nits in media such as Blu-ray Disc as 300 nits is a typical consumer TV.
Many HDR10 trailers seem to be at 200 or 300 nits.
Other studios map SDR white to PQ 100 nits as that’s a reference monitor spec.
Some big broadcasters and equipment vendors map SDR white and titles to HLG 75% code value (~200 nits)
Other program creators map SDR white and titles to HLG  100 nit (and it looks dark).
Many producers want options to set SDR white to 200 or 300 nits in HDR (PQ or HLG).
A broadcast standard for average brightness is needed or else channel surfing and commercial breaks will be unpleasant experiences with varying brightness levels. Compare this with the CALM act for audio levels.
Hopefully the industry will come to such an agreement within a few years.
Obviously Chrome will not set this standard, but will need means to support it.

Thanks,
Lars Borg  |  Principal Scientist  |  Adobe  |  p. 408.536.2723  |  c. 408.391.9479  |  borg@adobe.com


From: Fredrik Hubinette <hubbe@google.com<mailto:hubbe@google.com>>
Date: Wednesday, November 15, 2017 at 1:40 PM
To: "public-colorweb@w3.org<mailto:public-colorweb@w3.org>" <public-colorweb@w3.org<mailto:public-colorweb@w3.org>>
Subject: Principles of HDR in chrome
Resent-From: <public-colorweb@w3.org<mailto:public-colorweb@w3.org>>
Resent-Date: Wednesday, November 15, 2017 at 1:41 PM

First of all, I wanted to thank everybody who attended the colorweb discussion at TPAC. It was very interesting and helpful. I wanted everybody who was there (and everybody who wasn't) to have another chance to give me feedback on the documented I presented there, now that we've had some more time to think about it. Here is the actual document:

https://docs.google.com/document/d/1A__vvTDKXt4qcuCcSN-vLzcQKuchnYmu8TFMDseIZJE/edit<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.google.com%2Fdocument%2Fd%2F1A__vvTDKXt4qcuCcSN-vLzcQKuchnYmu8TFMDseIZJE%2Fedit&data=02%7C01%7C%7Cdba9496e037b4cfc119508d52c826617%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C636463860929188987&sdata=LFsiNCMAm%2BEJ75Qhu4JgTzo6Of1FJuRWPm%2F6JT3ezyU%3D&reserved=0>

I apologize in advance for any inaccuracies in here.
I you have comments, either share them on this list, or you can request comment access.

My next step is to bring the potential need for better brightness adjustment to industry groups. As pointed out in the meeting, the browser is not the right place for doing these adjustments, and if I can get OS or display makers to agree with me, then I won't have to implement it in Chrome, which would be great.

    /Fredrik "Hubbe" Hubinette