- From: Fares Alhassen <falhassen@google.com>
- Date: Fri, 28 Feb 2025 10:09:49 +0900
- To: jbowler@acm.org
- Cc: public-png@w3.org
- Message-ID: <CAE_ZyRCBiPFQdZKnfV8Za3shM6X67cFCgiN5QcWXOURo-t=W_w@mail.gmail.com>
Dear all, I have updates on accessing the ISO gainmap spec (ISO 21496-1), 1) ISO/TC 42 WG 18/23 will have a ballot on having a liaison to W3C. That ballot voting should end by the end of March 2025. 2) ISO 21496-1 is now in the DIS stage, meaning you can access the spec publicly now (https://www.iso.org/standard/86775.html). It is at bargain bin ISO prices, costing 65 CHF (presumably because it is considered in a "draft" stage). Sincerely, Fares On Fri, Feb 28, 2025 at 9:51 AM John Bowler < john.cunningham.bowler@gmail.com> wrote: > v4: cHRM chunk fix. Entirely backward compatible; existing decoders (ones > which actually check, which libpng no longer does) will simply reject the > chunk (harmless since the colourspace can't be represented anyway if the > spec is adhered to rigorousely), new decoders will handle it. > > Restart markers; argued about over and over again. Fully supported at > present but you can't do a complete parallel decode without knowing where > the rows start and end. That needs some information which can be cracked; > i.e. a cracker can use it to defeat a decoder which uses the restart > marker. The crack is basically undetectable until all the preceding blocks > have been decoded. If you just want to do LZ77 "inflate" in parallel no > biggy; doesn't require anything new. > > Complete parallel decode would be nice but it's so quaint and it requires > a critical chunk. Much much better to encode in blocks, not rows; > much-much-much faster even though the underlying data is the same. > Standard wisdom since the late '90s. > > John Bowler > >
Received on Friday, 28 February 2025 01:10:31 UTC