Pngout

[mreaves]

Pngout seems to cause certain problems on certain handsets…

I had a crash problem on a Sharp GX15, I finally traced this back to a crash when one PNG was loaded. I reverted back to the original version of this (not running it through conpng) and it worked. I have had similar problems on a couple of other handsets and reverting back to an original graphic always works.

It is obviously only certain png files that are affected, has anyone else has similar problems? Does anyone know what the problem is?

[shmoove]

I've seen it happen a few times too. I never bothered to really looked into what exactly was causing the problems, but it looks like some phones are more strict as to what parts of the png format can be taken out, and certain png compressor's on certain compression levels just take out too much.

shmoove

[grahamhughes]

You might have fewer problems with pngcrush, though the level of compression is not likely to be as good.

Cheers,
Graham.

[boinged]

Do you have example images that work and don't work?
Are you using the latest pngout as there was a new release on April 1st 2005?

Maybe we can get to the bottom of this or ask Ken Silverman if he has any ideas?

I guess it doesn't matter too much if it's just the GX15 although it might mean having a set of mega crushed pngs for devices with a small JAR/heap and a set of regular crushed pngs for the picky GX15

[DavidBlake]

Pngout seems to cause certain problems on certain handsets…

[...]

Does anyone know what the problem is?

Thank you for your interest in PNGOUT.

Some mobile devices ship with a version of zlib (1.2.1 and possibly earlier versions) that contains a bug that rejects valid deflate streams.

Both PNGOUT and PNGOUTWin have an option to work around this bug. The resulting file will have to have a few extra bytes.

If you are using PNGOUT, add

-zl121

to the command line. In PNGOUTWin, it is on the Compatibility tab under Settings.