Extremely low Bit Depth in paint.net 4.2.13

[Nyodex]

Updated to the latest version the other day. Since then, I've noticed that the Bit Depth is extremely low. It makes saving some of my work almost pointless.

[toe_head2001]

In the Save Configuration dialog, what Bit Depth are you selecting?

[Nyodex]

It’s always been set to Auto-Detect, which I’ve never had problems with until now.

[Rick Brewster]

Can you share an image that's causing these issues for you?

[Nyodex]

3 hours ago, Rick Brewster said:

Can you share an image that's causing these issues for you?

 - Auto-detect

 - 24/32-bit

 

It may be possible that this is only the case with more de-saturated colors, as I haven't had problems with more vibrant colors/images

[VxT]

idk tbh they fixed a lot of these issues as when I as editing and drawing a straight line back then the quality was trash but it looks like they fixed it with this new update. 

[Rick Brewster]

I can't reproduce any issue. Re-saving either of those images just results in the exact same image. Do you have the original image? I'm not sure if you shared the original or the saved ("low bit depth") version.

[BoltBait]

48 minutes ago, Rick Brewster said:

I can't reproduce any issue. Re-saving either of those images just results in the exact same image. Do you have the original image? I'm not sure if you shared the original or the saved ("low bit depth") version.

 

It seems easy to reproduce for me:

 

6 hours ago, Nyodex said:

 - 24/32-bit

 

Open the 32 bit image. Save as... badfile.png (auto bit depth)

 

The resulting file will have been saved at bit depth: 4  (according to the Windows file properties)

 

If you open the original image and then load this new file as a layer... then switch the layer's blend mode to XOR, you'll see the files are not identical.

 

The differences are subtle, but they're there.  In this case, saving as PNG is NOT lossless.

 

(Differences seen in Paint.NET v4.2.13.)

 

[Rick Brewster]

Alright, well that sounds straightforward. I'll make sure to fix this for 4.2.14.

[Rick Brewster]

Okay I've figured out the issue here. Palette generation was fine, quantization was fine ...... but then the down-conversion from 8-bit to 4-bit, even with a 4-bit palette, was broken. It's a bug in WIC (Windows Imaging Component), but I already had an 8-bit to 4-bit down-converter so I'm just using that code instead.

 

You can install this build of v4.2.14 which has the fix: https://www.getpaint.net/files/zip/test/paint.net.4.214.7530.38865.install.zip

 

[BoltBait]

1 hour ago, Rick Brewster said:

You can install this build of v4.2.14 which has the fix

 

I played around with this new build and it looks rock solid.  PNG is lossless again! 😎

[Rick Brewster]

That build also has some really important low-level rendering engine changes I've been working on for awhile. So, hopefully it isn't buggy!