Re: [Gdcm2] YBR_PARTIAL_422 and JPEG Baseline support

[Mihail I. <mih...@go...>]

Аt first sight seems that JPEG decoder has no problems with the file, good
news.
A little issue might be that it looks like YBR2RGB conversion has some
artifacts, it works well with YBR_FULL and YBR_FULL_422, but some colors of
YBR_PARTIAL_422 are wrong.

Here is the result
https://drive.google.com/file/d/1Wv8MBmn81i8EAahUT5FIinxFSb_q66a_/view?usp=sharing

Right image: colors-spaces were overridden (current behavior) and then
converted with YBR2RGB
cinfo.jpeg_color_space = JCS_UNKNOWN
cinfo.out_color_space = JCS_UNKNOWN

Left image produced by encoder directly, color-spaces are not overridden
cinfo.jpeg_color_space = JCS_YCbCr
cinfo.out_color_space = JCS_RGB

BTW, DCMTK's dcmcjpeg makes the same assumption and has exactly the same
issue, tried many options, always got the same result as left image.
Weasis opens image well.

Just FYI, it depends of course what is the desired result, not a request to
change something.

Kind regards,
Mikhail