JPG compression

[Jonish]

Hey guys, have there been any changes done to JPG compression when I save all images to separate files > JPG? Or, is there a way to tune it up?



Final JPG has noticable stripes in gradients compared to the VFB preview. I'm guessing that as the screen displays only 24bit colours, both of these should look more or less the same.
My current workflow is Photoshop-free, thanks to the improved VFB.

Cheers
Jonas

[natalia.gruzdova]

Hello Jonish,
When you save an image from VFB with the Save button the compression applied to the image currently can not be controlled (we are considering adding compression options in the VFB in the future as well).

You can ensure that .jpg quality is 100% if you set an auto-save option in Render Output > Save Image > Image Options.



Please note that .jpg images are always compressed and in you example you are comparing with the image from the VFB that is not compressed, but if you load saved .jpg back into VFB it will be the same.

If you need higher quality images please consider saving .png instead of .jpg which will give you reasonable compression without any quality degradation.

[Jonish]

Hello natalia.gruzdova, thank you for the tips!

And do you know what is the current hardcoded settings, is it somewhere between 70-100%?

The situation is very tricky and I can imagine that now you might have to juggle between different user workflows, just like we do due to various technical limitations, but... I welcomed the improved VFB, cryptomatte and lightmix. Those are great improvements in new versions!

1) Using the Render Output -> Save Image is not compatible with any postprocess done in VFB.
2) PNG clips away the gradient background from V-ray. Also, as cryptomatte, lightmix and others create additional channels, saving all as PNG takes terribly long time.

So save as JPG from VFB really is the Home option, especially if I want to avoid Photoshop.

Cheers
Jonas

[natalia.gruzdova]

Hi again Jonish,

And do you know what is the current hardcoded settings, is it somewhere between 70-100%?

I did some tests and it is about 85%.

1) Using the Render Output -> Save Image is not compatible with any postprocess done in VFB.

Valid point.

2) PNG clips away the gradient background from V-ray.

This one as well. Though you can note that if opened in Photoshop or Chaos Player the alpha will be stored.

This is why adding an option to choose quality and alpha channel options when saving from VFB similarly to the auto-save settings in the V-Ray Asset Editor will be a good solution. Which is currently considered as to how and when to be implemented.

[Micha]

This is why adding an option to choose quality and alpha channel options when saving from VFB similarly to the auto-save settings in the V-Ray Asset Editor will be a good solution. Which is currently considered as to how and when to be implemented.

This solution would be much appreciated.

[Jonish]

Hello natalia.gruzdova, thank you for your reply. Now that I'm thinking about it, maybe these soft gradients really could be extremely susceptible to JPG compression damage. Then the only solution really would be to manually ramp up the JPG quality to 100% in these images or to come up with a JPG alternative that would be widely adopted throughout graphic programs and web browsers / pages. I guess the first one would be easier to achieve.

Another little quality of life suggestion would be ability to check individual channels for do/not save when saving channels into separate files. For example cryptomatte is awesome in VFB edits, but useless later on in Photoshop postpro.

Have a nice day and thank you for looking into it!

Jonas

[Micha]

A general JPG quality of 100% would be great and if you need less, you can easily do this in batch process via XnView or other tools.

Another important problem would be to solve: if the user has saved an image as JPG, then he should not be offered PNG again the next time. Could this problem be fixed independently from the rest?