Post processing dithering can't be saved in 16bit format #106171

New Issue

Serge Lyatin · 2023-03-27T13:05:47+02:00

Serge Lyatin commented

2023-03-27 13:05:47 +02:00

System Information
Operating system: win10
Graphics card: 1050ti

Blender Version
Broken: never worked possibly

Short description of error
Dither applies to final image only if you save it in 8bit format.

Exact steps for others to reproduce the error
In attached file:

Render scene (F12) and save PNG file twice: in 8bit and 16bit formats

**System Information** Operating system: win10 Graphics card: 1050ti **Blender Version** Broken: never worked possibly **Short description of error** Dither applies to final image only if you save it in 8bit format. **Exact steps for others to reproduce the error** In attached file: * Render scene (F12) and save PNG file twice: in 8bit and 16bit formats

no_dither_16bit.blend

114 KiB

Serge Lyatin added the

labels 2023-03-27 13:05:48 +02:00

Philipp Oeser commented

2023-03-27 13:35:56 +02:00

Isnt this only needed when saving to 8bit?
16bit should not have banding (or other quantization errors)?

Or are you trying to hide some sort of other artifacts behind dithering? Compression artifacts?

If this is an artistic choice, why not add that with the compositor?

(pretty sure dithering only takes place when going from higher bitdepth to lower - but will check code - just trying to get the above questions out of the way first)

Isnt this only **needed** when saving to 8bit? 16bit should not have banding (or other quantization errors)? Or are you trying to hide some sort of other artifacts behind dithering? Compression artifacts? If this is an artistic choice, why not add that with the compositor? (pretty sure dithering only takes place when going from higher bitdepth to lower - but will check code - just trying to get the above questions out of the way first)

Philipp Oeser added

Status

Needs Information from User

and removed

Status

Needs Triage

labels 2023-03-27 13:36:24 +02:00

Serge Lyatin commented

2023-03-27 14:05:40 +02:00

Yes there is banding, so used some dithering, which was good in compositor, but later I realized that it wasn't applied to output sequence. Then started playing with settings until found out this format issue.
Maybe initial artifacts are rooted in my display device, but still curious about dithering limitation.

Yes there is banding, so used some dithering, which was good in compositor, but later I realized that it wasn't applied to output sequence. Then started playing with settings until found out this format issue. Maybe initial artifacts are rooted in my display device, but still curious about dithering limitation.

Philipp Oeser commented

2023-03-27 14:56:28 +02:00

Afaict, dithering only takes place in float --> byte conversion.
Since this is not needed for 16bit saving, I assume this is all working as intended.

To be 100% sure, I'll run this through the module to make a final decision.

Afaict, dithering only takes place in float --> byte conversion. Since this is not needed for 16bit saving, I assume this is all working as intended. To be 100% sure, I'll run this through the module to make a final decision.

Philipp Oeser added

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Post processing dithering can't be saved in 16bit format #106171