tiffsave fails with tile and jpeg compression and quality ≥ 90 on MacOS (v8.15.1) about libvips HOT 7 CLOSED

Ah well done! Yes I see a failure too, though only on macOS:

12:21 $ vips tiffsave k2_mono.jpg x.tif --tile --compression jpeg --Q 90
VipsJpeg: Unsupported color conversion request
VipsJpeg: Unsupported color conversion request
VipsJpeg: Unsupported color conversion request
wbuffer_write: write failed
unix error: Unknown error: -1
✘-1 ~/pics 

At a guess, Q>=90 is disabling chroma subsampling, and the very recent libtiff on macOS doesn't like this for greyscale images. I'll investigate.

from libvips.

Yes, mozjpeg seems to be missing some of the colourspace conversions that the other libjpeg implementations support. I've changed the way libvips disables chroma subsample for tiff jpeg write and it seems to work now.

This fix will be in 8.15.2, thanks for the report!

from libvips.

Hi @cavenel,

It's working for me:

16:13 $ vips tiffsave k2.jpg x.tif --tile --compression jpeg --Q 90
✔ ~/pics 
16:14 $ which vips
/opt/homebrew/bin/vips
✔ ~/pics 
16:14 $ vips --version
vips-8.15.1
✔ ~/pics 
16:14 $ 

That's an M2 mac mini with homebrew libvips.

Could you perhaps have a non-RGB image in input.tif? You can only save RGB and mono images with JPEG compression.

from libvips.

Hi @jcupitt,

That is strange, I tried with multiple input files, including jpeg input files (so RGB).
And the fact that it works with a different compression value (like --Q 85) is also confusing.
I will investigate more with other images tomorrow, and share one that fails.

from libvips.

Yes, that is puzzling! That was with brew update && brew upgrade as of an hour ago, if that makes a difference.

from libvips.

So, after some more testing, it seems like it only fails on grayscale images.
Take any image, open in GIMP, change mode to Grayscale and export as PNG or JPG. Then vips will fail to convert it to tiff with tile and compression bigger or equal to 90.
Here is an example of image that fails:

With the command:

vips tiffsave k2_g.jpg x.tif --tile --compression jpeg --Q 90

from libvips.

After some digging, it seems it's mozjpeg that's causing the problem. Here's a dockerfile that fails in the same way on ubuntu 23.20:

https://github.com/jcupitt/docker-builds/tree/master/libvips-mozjpeg-ubuntu23.10

I'll poke a bit more.

from libvips.