Hi Chris,
As the metadata is not mandatory, I think we need files with the correct CICP and with and without mDCv and cLLi so that we can test correct operation in all cases.
Do we also need some incorrect files, i.e. files with mDCv and cLLi but no CICP to check the failure mechanism?
Best Regards
Simon
Simon Thompson
Senior R&D Engineer
BBC Research & Development
From: Chris Blume (ProgramMax) <programmax@gmail.com>
Date: Wednesday, 6 December 2023 at 15:37
To: Seeger, Chris (NBCUniversal) <Chris.Seeger@nbcuni.com>
Cc: Portable Network Graphics (PNG) Working Group <public-png@w3.org>
Subject: Re: Conformance files in PQ, HLG, SDR-BT.709?
External: Think before clicking
I can hexedit in cICP values.
Although, maybe I should wait until we have mDCv and cLLi values as well? How long do you think it would take to get those values?
My thought is: I don't want to start distributing test images only to later tell people to use these new test images instead (when they don't yet have a way to see which ones are new/old).
But maybe it will take a while to get mDCv and cLLi values. So maybe it would be good to get some new test images sooner?
(Are these images public domain? Can we distribute them widely?)
On Wed, Dec 6, 2023 at 8:53 AM Seeger, Chris (NBCUniversal) <Chris.Seeger@nbcuni.com<mailto:Chris.Seeger@nbcuni.com>> wrote:
Hi Chris and All,
Do we have any conformance files in each format (PQ, HLG, SDR-BT.709)? I’ve got a number of developers who’d like to add the functionality into their apps. Once of them requested test files.
I’ve created test files if someone can add cICp chunks to them:
https://www.dropbox.com/scl/fo/a44vfxw3p21kvkh8nywpc/h?rlkey=v63ekq5y49kd4omg59ng9q3zr&dl=0
SDR CICP: 1-1-1 (Narrow and Full Range versions marked NR or FR)
PQ CICP: 9-16-9 (Full Range only as there is no benefit to NR PQ)
HLG CICP: 9-18-9 (Narrow and Full Range versions marked NR or FR)
I will send mDCv and cLLI values (just an example at a later date since cICp is most important to get to developers).
Thanks very much,
Chris Seeger
Director, Advanced Content Production
Office of the CTO
C: 551-238-3768
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