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troubles with 32bit float...

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troubles with 32bit float... Casey Connor 27 Apr 01:01
  troubles with 32bit float... Ken Moffat 27 Apr 02:45
Casey Connor
2017-04-27 01:01:05 UTC (almost 7 years ago)

troubles with 32bit float...

I'm having lots of issues with the 32bit tiffs that come out of G'MIC CLI processing in Linux (Kubuntu 16.10 in my case).

They don't open properly in GIMP, or most any other software. There is clearly something going wrong somewhere, but I'm not sure where to file a report as I'm not sure where the root cause may be (GIMP, underlying tiff libraries, or G'MIC, etc.) If anyone has any insight, I'd appreciate it.

When I apply a -median_files filter with G'MIC, it generates a 32bit float file that opens as all-white in GIMP. But I can change the precision (in GIMP) from 32bit-float to any integer format, and the image suddenly appears and I can work with it just fine. Here is a demonstration image: http://caseyconnor.org/pub/image/32bitfloat.zip (145MB)

Can anyone reproduce that? I've asked here before without luck, but I've seen on other forums that I'm not the only one with this issue. (This happens in any recent version of GIMP on Linux or Windows for me, but most recently tested in otto-kesselgulasch repo commit 2944dbd.)

I tried to generate a smaller simple example starting with a 100x100 pixel image, 16bit integer precision (same thing happens with 8bit): I make a simple gradient, save it to png or tif, process through G'MIC, and open the result in GIMP. Result: image is all white, and in this case changing precision does *not* make the real image appear -- I can't see the image no matter what I do. Here is a zip file with the original and the gmic processed version that won't open in GIMP: http://caseyconnor.org/pub/image/smallexample.zip

The KDE image viewer (gwenview) shows the image differently every time it opens it: sometimes a corrupted version, sometimes a line across a black background, and the line changes color every time the image is opened. (I mention this only in case it points at some system library issue.)

If I open the 32bit float G'MIC images in Hugin, they open fine, but the resulting 32bit float output from Hugin can not be opened in or processed by GIMP in linux or windows.

AN important note: I can open all of these images (post-G'MIC, big image or small 100x100 image) in Luminance HDR: it seems to have no trouble with them.

Any thoughts? Are there GIMP bugs here to be addressed? Can anyone reproduce this?

I've had some success using G'MIC in 16bit integer mode (by appending ",ushort" to the file name); my main goal here is to sort these bugs out.

Thanks!

Ken Moffat
2017-04-27 02:45:07 UTC (almost 7 years ago)

troubles with 32bit float...

On Wed, Apr 26, 2017 at 06:01:05PM -0700, Casey Connor wrote:

I'm having lots of issues with the 32bit tiffs that come out of G'MIC CLI processing in Linux (Kubuntu 16.10 in my case).

They don't open properly in GIMP, or most any other software. There is clearly something going wrong somewhere, but I'm not sure where to file a report as I'm not sure where the root cause may be (GIMP, underlying tiff libraries, or G'MIC, etc.) If anyone has any insight, I'd appreciate it.

The problem with tiff is that it isn't a simple format, it's a specification which has been described as Thousands of Incompatible File Formats (thanks, wikipedia). When I was trying 16-bit images with gimp-2.9 using ufraw, I used to see lots of messages about unexpected features in the file format. In the end I moved to pngs, and for my amateur pics 8-bit is actually good enough.

So the first question is: can you use a different file format (I'm only minimally familiar with G'MIC, used as a plugin, and I have no real understanding of what you are doing) ?

When I apply a -median_files filter with G'MIC, it generates a 32bit float file that opens as all-white in GIMP. But I can change the precision (in GIMP) from 32bit-float to any integer format, and the image suddenly appears and I can work with it just fine. Here is a demonstration image: http://caseyconnor.org/pub/image/32bitfloat.zip (145MB)

I recognize that G'MIC is not only for the gimp, but since it works as a plugin working on opened images - can you use the plugin to do what you are doing ? If not, I would be tempted to ask at G'MIC because they seem to be active and some of their output clearly works in the gimp. If they say it's not their problem, perhaps they can narrow down whose problem it might be.

Sorry this probably isn't a lot of help.

ĸen

I live in a city. I know sparrows from starlings.  After that
everything is a duck as far as I'm concerned.  -- Monstrous Regiment