fpng

The developer who asked for the faster compression formats has later solved the problem himself: https://github.com/richgel999/fpng It turns out that deflate can be much faster when implemented specifically for PNG data, instead general-purpose compression (while still remaining 100%-standard-compatible).

> I would bet that these days, generating or decoding PNGs is the bottleneck almost nowhere The bulk of my game's startup time is spent decoding PNGs via libpng. There are some alternatives to libpng like fpng[1], or alternate image formats like QOI[2] These both exist because png is slow and/or complicated. [1] https://github.com/richgel999/fpng [2] https://github.com/phoboslab/qoi (discussed here: https://news.ycombinator.com/item?id=29661498)

> The CRC and the compression are non-trivial. CRC is a table and 5 lines of code. That's trivial. >zlib is 23k lines It's not needed to make a PNG reader/writer. zlib is massive overkill for only making a PNG reader or writer. Here's a tiny deflate/inflate code [2] under 1k lines (and could be much smaller if needed). stb[0] has single headers of ~7k lines total including all of the formats PNG, JPG, BMP,. PSD, GIF, HDR, and PIC. Here's [1] a 3k lines single file PNG version with tons if #ifdefs for all sorts of platforms. Removing those and I'd not be surprised if you could not do it in ~1k lines (which I'd consider quite simple compared to most of todays' media formats). >Of course they're not common formats so you're stuck with complex formats like PNG BMP is super common and easy to use anywhere. I use flat image files all the time f

It depends on the implementation. fpng can beat QOI in both speed and compression ratio https://github.com/richgel999/fpng

The space cost is negligible, but the time cost for the encoder is real. Since most decoders do verify checksums, you can't just skip it. Take fpng[1] as an example, which tries to push the boundaries of PNG encode speed. > The above benchmarks were made before SSE adler32/crc32 functions were added to the encoder. With 24bpp images and MSVC2022 the encoder is now around 15% faster. I can't see the total percentage cost of checksums mentioned anywhere on the page, but we can infer that it's at least 15% of the overall CPU time, on platforms without accelerated checksum implementations. [1] https://github.com/richgel999/fpng

There are a lot of dimensions on which QOI could be improved, but most cases involve trade-offs, e.g. more complexity for better compression. The areas where QOI could have been strictly better, the dimensions on which it is not on the Pareto frontier, are more meaningful criticisms — missed opportunities. This summer I spent a lot of time researching lossless compression formats as a streaming format for our 3D capture and reconstruction engine. QOI was on our list too. My biggest criticism about QOI is that in many cases it doesn't compress at all, or even increases size. It works well on the demo images that come with the package but these are carefully selected. It also works well on high-res, high-quality images with lots of single-color background and/or smooth gradients. But give it grainy, noisy, smaller-format images and it compl

This was actually considered, and other libraries do ignore checksums, or at least have options to: https://github.com/richgel999/fpng/issues/9

I wonder how fpng[1] would compare- a lossless speed optimized png compressor. Oh! The author Rich screenshoted[2] a really nice deck[3] that also boasts fpnge[4] and fjxl[5], both of which are even faster, both use AVX2 (or neon for FJXL). Notably fjxl is in the reference libjxl tree. I'm not sure what if any constraints fast mode has, what it takes to use. The article uses cjxl, which does not run the fjxl fast mode, and further, fast mode was added after this article was written[6]. Other notes on jpeg-xl: it has progressive rendering. It has hdr! The deck on FJXL & FPNGE is epic. Thanks Quote Ok Image (QOI) format for setting the fire on this all!! [1] https://github.com/richgel999/fpng [2] https://twitter.com/richgel999/status/1485976101692358656 [3] https://www.lucaversari.it/FJXL_and_FPNGE.pdf [4] https://github.com/veluca93/fpnge

In the other direction, you can target a subset of PNG to get less optimized images but with QOI-like encode and decode speed: https://github.com/richgel999/fpng

I think QOI inspired the creation of https://github.com/richgel999/fpng which creates standard PNGs and compares itself directly to QOI.

If QOI is interesting because of speed, you might take a look at fpng, a recent/actively developed png reader/writer that is achieving comparable speed/compression to QOI, while staying png compliant. https://github.com/richgel999/fpng Disclaimer: have not actively tried either.