CPNG, a backwards compatible fork of PNG

#1

Post by dirkf » Thu, Dec 07, 2023, 8:47 AM UTC

CPNG, a backwards compatible fork of PNG
richg42.blogspot.com

Re: CPNG, a backwards compatible fork of PNG

#2

Post by ebb_earl_co » Sat, Dec 09, 2023, 4:07 PM UTC

> Why continue messing with PNG at all? Because if you can figure out how to squeeze new features into PNG in a backwards compatible way, it's instantly compatible with all browsers, OS's, engines, etc. This is valuable

What a brilliant paragraph. I wish this developer all the success in the world.

Re: CPNG, a backwards compatible fork of PNG

#3

Post by ericskiff » Sat, Dec 09, 2023, 4:15 PM UTC

This is wonderful. What a great way to continue innovation without facing the adoption hurdles of a new format

Re: CPNG, a backwards compatible fork of PNG

#4

Post by brookst » Sat, Dec 09, 2023, 4:18 PM UTC

Very cool, and I hope it sees adoption.

Also speaks to either wise or lucky design of PNG itself, that it can support these kinds of backwards-compatible extensions.

Re: CPNG, a backwards compatible fork of PNG

#5

Post by Voultapher » Sat, Dec 09, 2023, 4:37 PM UTC

That's really cool! I stumbled across libpng being 10+x slower to encode than jpg and tiff at work. The LOGLUV32 part is very clever. I particularly like the tonemapped fallback and general idea to build on top instead of reinventing. That said I hope these format extensions don't end up in compatibility hell, where viewing the full info image is hit or miss between different CPNG decoders.

Re: CPNG, a backwards compatible fork of PNG

#6

Post by vzaliva » Sat, Dec 09, 2023, 4:54 PM UTC

How this compares to WebP?

Re: CPNG, a backwards compatible fork of PNG

#7

Post by notfed » Sat, Dec 09, 2023, 5:00 PM UTC

This sounds pretty amazing.

For CPNG-aware libraries, the performance improvements sound impressive.

For old (CPNG-unaware) libraries: should I expect any performance drop reading a CPNG image compared to if the image had remained PNG? Similarly, how much larger will a CPNG be than a PNG?

Re: CPNG, a backwards compatible fork of PNG

#8

Post by kibwen » Sat, Dec 09, 2023, 5:05 PM UTC

vzaliva wrote: post #6

How this compares to WebP?

I didn't even realize that WebP had an optional lossless compression mode.

Re: CPNG, a backwards compatible fork of PNG

#9

Post by fbdab103 » Sat, Dec 09, 2023, 5:29 PM UTC

What is the modern power ranking on image formats?

For lossless, what is typically the most efficient size wise? Decompression speed?

For lossy?

I am not in a situation where these micro-optimizations mean much to me, and always default to png, but curious to know where the state of the art is today.

Re: CPNG, a backwards compatible fork of PNG

#10

Post by gumby » Sat, Dec 09, 2023, 5:33 PM UTC

I loved reading this even though I personally have zero need myself. I enjoyed the rationale and he engineering.

The world needs more work like this. I’m talking about the thoughtful image format but also that applies to the write up too.