Re: Conversions for HDR Canvas Specification

> Please, no long numbers!

I do not understand this blanket statement.

The accuracy of individual constants within an expression should be
sufficient to achieve the desired accuracy for the entire expression.

For example, it would make no sense to specify π = 3.14 in f(x) = π·d
if f(x) is intended to compute the circumference of a circle to an
accuracy of ±0.00001.




On Thu, Jun 17, 2021 at 2:39 PM Lars Borg <borg@adobe.com> wrote:
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> Please, no long numbers!
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> And I’m not alone on this.
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> Lars
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> From: Chris Lilley <chris@w3.org>
> Date: Thursday, June 17, 2021 at 3:00 AM
> To: "public-colorweb@w3.org" <public-colorweb@w3.org>
> Subject: Re: Conversions for HDR Canvas Specification
> Resent-From: <public-colorweb@w3.org>
> Resent-Date: Thursday, June 17, 2021 at 3:00 AM
>
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> On 2021-06-16 11:53, Simon Thompson - NM wrote:
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> Hi all,
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> I’ve added a list of suggested colour forward and reverse transforms between extended-sRGB, extended-linear-sRGB and bt2100-hlg and a suggested simple tone-mapping for displaying bt2100-hlg on an sRGB display to issue #50 - https://github.com/w3c/ColorWeb-CG/issues/50.  I’ve tried to follow the style of the example in TTMLv2 provided by Pierre.
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> I can recalculate the matrices to a different number of significant figures if necessary – is there a consensus on accuracy levels for web operations?
>
> In general, since "space of the printed publication"is no longer a concern, I prefer to list to full precision.
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> I have seen several problems arising from round-off errors and round-tripping, so there is no good reason to round off.
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> Would Dolby colleagues be able to add the bt2100-pq versions to the list?  There is a PQ example in Pierre’s TTMLv2 link.
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> Best Regards
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>
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> Simon
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> Simon Thompson
> Senior R&D Engineer
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>
>
> --
>
> Chris Lilley
>
> @svgeesus
>
> Technical Director @ W3C
>
> W3C Strategy Team, Core Web Design
>
> W3C Architecture & Technology Team, Core Web & Media

Received on Thursday, 17 June 2021 22:29:43 UTC