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Re: [csswg-drafts] [cssom-1][mediaqueries-5][css-color] Dealing with bi-plane (video/graphics) when reporting values (#4471)

From: mwatson2 via GitHub <sysbot+gh@w3.org>
Date: Thu, 31 Oct 2019 00:59:23 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-548173254-1572483563-sysbot+gh@w3.org>
@chcunningham is correct that these are distinct concepts. Color gamut, color depth and dynamic range are all distinct things that can vary independently, though not all combinations are in use.

In particular, BT.2020 color gamut is used with both standard dynamic range and high dynamic range as is 10 bit color depth. Color depth is about precision, not range. (btw, Example 3 [here](https://drafts.csswg.org/cssom-view/#screen) is wrong about this).

To further clarify the problem description, given media in a specific format we must ask first whether the media *can* be rendered at all in some reasonable form and second whether it *should* in the case the site has a choice of formats. The first is a question about UA support for the codec and pixel data format **and** it's ability to map that meaningfully to the output device. The second is a question about the raw capability of the output device.

We separate these questions because in some cases the site might not have a choice of formats and is only interested in whether the format can be rendered or not. If the site has a choice of formats, all of which can be rendered, it needs to know which is worthwhile and will produce the best result. Unless you have no choice, there is no point sending HDR if the output device is SDR, even if the UA has the capability to map it down.

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Received on Thursday, 31 October 2019 00:59:25 UTC

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