Charter Review

Christian: charter looks OK to me. Jeffrey is concerned that the new compression algorithm is not backwards compatible. Should they introduce a new media type for that?

Martin: I think Jeffrey is entirely right. If you can't consume the content without new code, it's a new format.

Christian: 4th ed includes HDR/SDR. 5th edition includes new compression algorithm that will break compatibility with existing image files. Thoughts so far are that we're fine with it, but they need to make sure you can treat the new images files safely. Martin suggestetd that if you need new code to interpret it, then it's a breaking change.

Yves: Same issue with all the containers that embed differnt formats. E.g. video like Matroska. I treat this as the same case.

Matthew: My read was that if it needs new code to interpret it, it's a new format. A way to make it safe is to duplicate the old format, but then you've lost the benefit. Don't see how this is fine if that's the way to solve it. That would be hard.

Jeffrey: There's a comment Christian linked to in the discusion that makes the point I would make: if existing decoders can't decode new files, then it's a new format. It's true that's been done in video codecs, but I think it's new for images, and we should hold that line. We also have 2 new generations and 3 new formats for images WebP, AVI..., JPEG XL that all do better than PNG. Any suggestion to break compatibility with PNG needs to be compared to those new formats and justify itself. We should be sceptical of any backwards-incompatible changes.

Christian: Do the same review resolutions apply to charter reviews?

Jeffrey: There are no rules; we can use what's appropriate. The text of the charter review is more appropriate than the code - it'll be pasted into the strategy repo thread.

Christian: I'd remove the resolution, add what you said to the proposed comment, and then we can discuss again. Will post to (TAG's) private repo for discussion.