Topic: PNGGauntlet

[KingKuros]

I just downloaded and installed the PNGGauntlet.  Before I try it, I want to ask something.  How should I set the PNGOut options?  How is yours set?

[JonLeung]

I just check "Brute Force Compression" on.

[RT 55J]

Be warned. It takes a very long time.

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Dot? Dot. Dot!

[JonLeung]

I think it depends not only on the speed and memory of your computer, but on how "compressible" the original image is.  I've seen large files go through very quickly (as in, seconds) and not compress much, while other large files take all day but they compress a lot more.

[DarkWolf]

I'm not looking forward to running through the Faery Tale Adventure world map through PNGGauntlet.

[Maxim]

Something I recently realised:



PNG images have a "filter" setting to try to get better compression. A filter is run over the image before compression to try to make it more compressible; there are 5 filters available.



For paletted images, PNGOut assumes that filter 0 (no filter) will do best because it seems to go well with pixelly images and images with a small number of colours. For true-colour 24-bit images, PNGOut assumes filter 5 (mixed) will work best because true-colour images are generally photographic and thus have smooth colour gradation and a large number of colours.



However, game maps generally aren't photographic and generally have less than a thousand different colours. Thus, if your map contains more than 256 colours, it'll probably compress a lot better if you override PNGOut's filter selection by using the "/f0" parameter.



Example:



D:\Desktop\Maps>pngout "Wolfenstein3-D-Episode2-Floor1.png"

 In: 1503058 bytes               Wolfenstein3-D-Episode2-Floor1.png /c2 /f5

Out: 1336510 bytes               Wolfenstein3-D-Episode2-Floor1.png /c2 /f5

Chg: -166548 bytes ( 88% of original)



D:\Desktop\Maps>pngout "Wolfenstein3-D-Episode2-Floor1.png" /f0

 In: 1336510 bytes               Wolfenstein3-D-Episode2-Floor1.png /c2 /f5

Out:  961513 bytes               Wolfenstein3-D-Episode2-Floor1.png /c2 /f0

Chg: -374997 bytes ( 72% of original)



Filter 0 cut an extra 366KB from a 1305KB image.

[TerraEsperZ]

A new version of PNGGauntlet is now available as well as a new version of PNGOut which it requires, and maybe it's just me, but I'm absolutely unable to reduce the bit depth anymore and always end up with 24 bit colors even if the image has less than 256 colors. JonLeung, you'd better try it out before adopting it completely just in case.



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Current projects: Ristar-The Shooting Star (Gen), Sonic The Hedgehog (Gen), Sonic CD (Sega CD), Mega Man Zero (GBA), Battletoads (NES), Bucky O'Hare (NES)

[Maxim]

It seems PNGGauntlet is buggy - it is only running PNGOUT once, and ignoring your colour depth settings. I suggest avoiding it and/or contacting the author with a few sample images.

Personally, I just do pngout /c3 /d0 and it's usually the best. For images that are more than 256 colours, pngout /f0. Worst case, run both - PNGOUT will keep the smallest.