Felix Bünemann

Hmm, the ImageMagick and OpenJPEG encoders linked above also both set dx and dy the same on all planes, instead of keeping it to 1 on the first plane, which...

Oh, I just noticed vips only uses YCbCr when subsampling is enabled, so if it's disabled we use RGB: https://github.com/libvips/libvips/blob/master/libvips/foreign/jp2ksave.c#L818 But there are different codepaths for subsample and save_as_ycc, which...

Argh, I had the wrong vips binary symlinked in my header tests. So I was testing the original code all the time. Essentially it doesn't seem to matter: Either set...

@jcupitt There seems to be a problem with the MCT (Multi-Component-Transform) header: If I compress with `opj_compress` it sets mct to 1, which is RGB->YCC conversion, but if I compress...

In `opj_compress` by default RGB->YCC transform is used, if there are three components or more. I can manually set it to `-mct 0` (no transform) or `-mct 1` (RGB->YCC). The...

I'll try asking on the OpenJPEG Google Group.

I ended up no asking on the group, but doing some research instead. MCT (Multi Component Transform) is an addition to the JPEG 2000 standard that was added to help...

I noticed you already changed the default for subsample_mode, so I've made a PR with the change to the "auto" behaviour.

I used dynamic linking: `clang bug.c -g $(pkg-config --cflags --libs vips) -o bug`. To compile libvips with debug info `./configure CFLAGS=-g LDFLAGS=-g` should work. Btw. today it crashes for me...

I haven't had much luck with valgrind on 10.13, even with master.