Re: [EXTERNAL] [PNG] Upcoming meeting topics (Fourth Edition)

Also, a bunch of us would like to suggest adding “Gain Curves” with “Gain Maps”.

-Chris


From: Chris Blume (ProgramMax) <programmax@gmail.com>
Date: Thursday, March 27, 2025 at 9:25 AM
To: Seeger, Chris (NBCUniversal) <Chris.Seeger@nbcuni.com>
Cc: Portable Network Graphics (PNG) Working Group <public-png@w3.org>
Subject: Re: [EXTERNAL] [PNG] Upcoming meeting topics (Fourth Edition)
Works for me :)

On Thu, Mar 27, 2025 at 8:51 AM Seeger, Chris (NBCUniversal) <Chris.Seeger@nbcuni.com<mailto:Chris.Seeger@nbcuni.com>> wrote:
Hi Chris B.,

I’d like to suggest changing dWLm to rWtm (Reference White Metadata).  This follows discussions in other standards groups.  HDR Reference White Metadata would describe diffuse white values other than “Nominal HDR Reference White” which equals 203nits.

Best,
Chris Seeger

From: Chris Blume (ProgramMax) <programmax@gmail.com<mailto:programmax@gmail.com>>
Date: Thursday, March 27, 2025 at 7:52 AM
To: Portable Network Graphics (PNG) Working Group <public-png@w3.org<mailto:public-png@w3.org>>
Subject: [EXTERNAL] [PNG] Upcoming meeting topics (Fourth Edition)
Hello everyone,

We are cutting a feature branch for Third Edition and continuing work onto Fourth Edition.
So our topics for discussion are Fourth Edition items:

  *   negative cHRM values
  *   Inserting deflate restart markers into a stream where a new scanline with compatible filter allows -- add new chunk to indicate the location of those restart markers

     *   possibly also not at scanline w/ compatible filter locations -- we'll want to gather information on deflate decode time vs. other png work time to see if parallelizing just that portion is worth it

  *   Compression methods other than deflate
  *   Gain maps
  *   Generic image data
  *   dWLm
Possible other topics which have been mentioned but aren't in a Github issue:

  *   Boundaries other than scanlines. For example, blocks.

There are probably more topics I'm forgetting right now. Feel free to reply with them so they get included. But this will be more than enough for one meeting. :)

See you Monday!