Unsupported color conversion request with DCM files.

[inputfalken]

Hi not sure if this a bug but I figured i would start with a question here.

I'm trying to convert dicom files whose image compression is JPEG lossless compression. I have tried both with this library and the
imagemagick CLI tool and get the same error.

Like the following example magick.exe foo.dcm bar.jpg -> Unsupported color conversion request @ error/jpeg.c/JPEGErrorHandler/356.
When I run the verbose flag i get the error the moment it want to process the pixel data.

My theory is that it's due to the following:

Lossless RGB JPEG files
This requires the SmartScale feature, which is not supported.
Source: https://github.com/ImageMagick/jpeg-turbo?tab=readme-ov-file#not-supported

I'm wondering what my options are. I would love to be able to continue using your .NET solution of imagemagick. ❤️

[dlemstra]

Can you share a dcm file that reproduces this so I can check with a debugger what is happening.

[dlemstra]

I have just created this issue: libjpeg-turbo/libjpeg-turbo#793

[dlemstra]

We got a response and it looks like this should be fixed in the library that wrote this file. I don't think we should add a patch for this in ImageMagick because this seems to be an edge case.

[inputfalken]

That's fantastic to hear! Thank you for the time and effort you put into my question.

Sounds good to wait for libjpeg-turbo to fix it. 👍

But the plan then is to wait for libjpeg-turbo to perform the fix. Followed by a new version of ImageMagick where the fix has been applied? If so, would it be considered a patch version for ImageMagick to use the updated libjpeg-turbo? I'm mainly wondering if this can be released fairly shortly.

[dlemstra]

I think you need to read me answer and the referenced issue again 😄. "the library that wrote this file" means the vendor that created this dicom file.

[inputfalken]

My bad, I thought you ment libjpeg-turbo was the library. 😅

But i see now you said library that wrote, I will provide this information to the vendor. 👍

[dlemstra]

Make sure you keep following the conversation in the issue that I opened it contains some tips for LEADTOOLS.

[inputfalken]

I have been looking over it during the last days. 🙂

I'm planning to contact them and reference the issue you created.

[inputfalken]

Hi again, I just wanted to inform you that after a long conversation where I referenced both this and the libjpeg/turbo issue.

They have concluded that everything looks fine on their end. And they will not do anything with their lossless JPEG implementation.