How to save a TIFF image format CMYK with Alpha channel in C#

问题

I'm developing an application that loads a TIFF image, concatenate it with another image I created in runtime and save the concatenated one without changing format of the original TIFF.

I'm able to do that using TiffBitmapEncoder & TiffBitmapDecoder + BitmapSource.CopyPixels - With CMYK tiff images only

A special case is TIFF CMYK with an additional Alpha channel (yes, it's 40bits depth), and I'm stuck. I need to use TiffBitmapDecoder to save the file after modification, but I can only specify format PixelFormats.Cmyk32 for it, and that is not the correct format in case having Alpha channel. The original format wasn't recognizable by TiffBitmapEncoder fyi..

What can I do/try here to achieve my purpose?

来源：https://stackoverflow.com/questions/65266182/how-to-save-a-tiff-image-format-cmyk-with-alpha-channel-in-c-sharp