You need to sign in or sign up before continuing.
trouble when transcoding 4:2:2 or 4:2:0 jpeg
Hi,
I've found something that look like an issue transcoding jpeg to jpegxl.
It happens on Fedora 31/clang version 9.0.0/64 bits.
If I transcode a 4:4:4 jpeg to jpeg xl, everything's fine.
cjpegxl --jpeg_transcode gator444.jpg gator444.jpx
but not with 4:2:2 or 4:2:0
convert gator444.jpg -sampling-factor 4:2:0 -quality 100 gator420.jpg
./cjpegxl --jpeg_transcode gator422.jpg gator422.jpx
convert gator444.jpg -sampling-factor 4:2:2 -quality 100 gator422.jpg
./cjpegxl --jpeg_transcode gator420.jpg gator420.jpx
It produce files with wrong colors and half greyscale.
And if I try to transcode back to jpeg :
djpegxl --jpeg gator420.jpx gator420.jpx.jpg
=> wrong colors and 3/4 greyscale.