Re: [EXTERNAL] Feedback re: Broadcast vs Computing assumption

If you look at the intent of sRGB I don’t see a conflict.

Back in 1996 the computers weren’t powerful enough to color manage video.

Broadcast, gamma 2.4, was designed for viewing in a dark room.

sRGB was designed for a bright office room.

The result was that unconverted 709 video looked good in both office and living room viewing environments.

We don’t want to convert between these spaces as that would not take into effect the viewing environments.

 

Lars

 

On 6/14/23, 2:22 AM, "Seeger, Chris (NBCUniversal)" <Chris.Seeger@nbcuni.com> wrote:

 

EXTERNAL: Use caution when clicking on links or opening attachments.

 

The only conflict I see between broadcast and computing is with sRGB Gamma 2.2 which conflicts with broadcasts BT.1886 display gamma 2.4

 

But as Pierre notes, the convergence between the two industries has produced many desktop displays that support BT.1886.  Can we converge around BT.1886 in desktop computing and on the canvas?

 

In broadcasting we use reference white as an anchor in a single-master workflow. Graphic White is usually the same or very close to reference white.  SDR consumer displays use approximately the same peak white as HDR reference white (see our display luminance survey here):

 

https://www.dropbox.com/s/8f8ceh2a8f3zhqv/Summaries%20-%20MovieLabs-NABA-NBCU%20SDR%20Consumer%20TV%20Luminance%20Survey.pdf?dl=0

 

An “Effective Gamma” can be calculated by measuring midgray against reference white and it should be consistent in a reference environment between both computing and broadcasting.  The effective gamma can be calculated in both SDR and HDR.  HDR Midgray=26nits; Reference White=203nits as per BT.2408 and will result in an “Effective Gamma” of 2.4.

 

Best,
Chris

 

 

From: Pierre-Anthony Lemieux <pal@sandflow.com>
Date: Wednesday, June 14, 2023 at 12:33 AM
To: public-colorweb@w3.org <public-colorweb@w3.org>
Subject: [EXTERNAL] Feedback re: Broadcast vs Computing assumption

Good morning/evening,

Before delving into solution space, e.g. gainmaps, I would like to
challenge the assumption, laid out in Chris Cameron's presentation,
that "broadcast" and "computing" are fundamentally in conflict.

There has in fact been a convergence in the devices, and viewing
environments, used for "broadcast" and "computing": mobile devices are
used to enjoy linear content, games and balance checkbooks.

Graphics content regularly show up in "broadcast" content in the form
of UIs and subtitles/captions.

Conversely, "broadcast" content regularly shows up in computing, e.g.
gallery of scene stills, lens flares, etc.

A significant part of the expansion of the web platform in the past
decade has been closing the gap between  balancing checkbooks and
watching movies passively.

So I do not see a fundamental conflict between "broadcast" and "computing".

Maybe the terms could be improved? Perhaps there is a difference
between how linear experiences and interactive experiences are
authored/rendered?

We need to be more specific before trying to find solutions.

Below are specific points/questions.

Best,

-- Pierre

> "Relatively static, controlled environment" vs "Dynamic, uncontrolled environment."

The viewing environment has become extremely similar since consumers
watch TV and perform computing tasks on largely the same devices and
environment, e.g. mobile devices.

Do you mean that there are two classes of content and/or experiences:
one interactive and one linear?

> "Usually the only content on-screen" vs "Shares screen with other applications (SDR, HDR, and other)."

TV content is often overlaid with subtitles and captions, and is often
mixed with other content, e.g. episode/title/scene galleries.

> "Graphics white is largely irrelevant." vs "Graphics white is a critical anchor point, especially for UI and text."

All content needs to be comfortable to watch, which means neither too
bright nor too dark.

> "A display is HDR if it can display HLG and PQ content (with reasonable brightness & contrast)" vs "A display is HDR if it can go brighter than graphics white (HDR headroom > 1)"

An HDR display is defined by its physical characteristics, e.g.
intraframe min/max luminance, monotonicity of gray scale, etc. How is
it related to HLG/PQ encoding and/or brighter than graphics white?