[PNG] Meeting minutes - Apr 27, 2026

Hello everyone,

Attached are the meeting minutes from the Apr 27, 2026 meeting.

Executive summary:

   - Restart markers will be indicated by empty IDAT chunks. We felt this
   was better than storing file offsets which are fragile and become incorrect
   if a tool alters the image data.
   - Since it is beneficial to know which scanline a restart marker is
   associated with, a separate chunk will list out the scanlines. This seems
   forward and backward compatible enough. We don't know of any existing tools
   that output empty IDAT chunks. And any new tool that is aware will know to
   update the new ledger chunk.
   - SMPTE ST 2094-50 is nearing completion.

Our next meeting is May 11th, 2026. See you then!
- Chris Blume