Is there a solution for this case?

[Marcio.ciconne]

Good afternoon friends, I would be grateful if someone could help me!

I have an archive of a show that was filmed from cameras with little ability to capture colors and lighting, so to make it closer to real lighting I needed to calibrate the brightness, contrast, and correct the colors.
The big problem is that when you change the lighting of a video with low light and few colors, you end up having ''damages'' in the image in addition to the artifacts and grains of forced lighting. I manage to remove these grains of lighting with NeatVideo, but there is a defect that I cannot remove, which would be this gradient of the blue lighting that cannot be uniform...
I read in some articles that this could be about 8-bit images (frames) that suffer large changes in brightness, they face this unpleasant gradient effect in the frame, I don't know if this is the real problem.
Does anyone know a technique to remove this color splitting effect and make them smoother and more uniform?
Detail: The video is still in low quality (704 x 576) and I will upscale the image after finding out if it is possible to solve the problem.


Thanks

[johnmeyer]

The "gradient" you see is usually called "contouring." It results from not using enough bit depth to encode the color. I don't think I have seen a script which attempts to solve that problem, but my sense is that something like that would be possible.

[Marcio.ciconne]

The "gradient" you see is usually called "contouring." It results from not using enough bit depth to encode the color. I don't think I have seen a script which attempts to solve that problem, but my sense is that something like that would be possible.

Hi Yes,
I thought it was a problem with not having enough bits for the colors.
I tried converting each frame from 8 to 16 bits using Photoshop, but I returned the frames to Vegas and it didn't help, the outline remains, I don't know if the conversion was fake. Could there be a way to artificially convert an 8-bit video to 16-bit 😔

[Cornucopia]

If it starts with inadequate color depth, simply changing the bitdepth from 8bits to 10/12/16 bits does nothing except store a lot of extra 0s in those new bit levels. You need an algorithm that interpolates to generate those missing intermediate levels (hopefully in a smart & visually pleasant way).
And then, if you must return to a limited bit pallette, you should dither prior to rounding/truncation in order to retain the visual equivalent of those intermediate levels.


Scott

[Marcio.ciconne]

If it starts with inadequate color depth, simply changing the bitdepth from 8bits to 10/12/16 bits does nothing except store a lot of extra 0s in those new bit levels. You need an algorithm that interpolates to generate those missing intermediate levels (hopefully in a smart & visually pleasant way).
And then, if you must return to a limited bit pallette, you should dither prior to rounding/truncation in order to retain the visual equivalent of those intermediate levels.


Scott

I understand,
But is there any tool that I can do this?

[jagabo]

AviSynth has filters for that:

LWLibavVideoSource("mp4.mp4") 
TDecimate(Cycle=5, CycleR=3) # remove duplicate frames
GradFun2db() # reduce posterization, alternate filter GradFun3()
ConvertBIts(10)
SMDegrain(thsad=100, tr=2, PreFilter=4) # temporal smooth a bit

You need to encode with a high bitrate and/or use a 10 bit encoder to keep them from coming back.

[Marcio.ciconne]

AviSynth has filters for that:

LWLibavVideoSource("mp4.mp4") 
TDecimate(Cycle=5, CycleR=3) # remove duplicate frames
GradFun2db() # reduce posterization, alternate filter GradFun3()
ConvertBIts(10)
SMDegrain(thsad=100, tr=2, PreFilter=4) # temporal smooth a bit

You need to encode with a high bitrate and/or use a 10 bit encoder to keep them from coming back.

Wow, it turned out perfect buddy!
With this Script you sent, can I achieve this effect?

[jagabo]

That's the script I used. I encoded as 10 bit HEVC with Intel's QSV (GPU) encoder via ffmpeg. You might need to add more grain if you intend to encode with an 8 bit encoder.

Note that the short sample has lots of duplicate frames. I removed those (maybe a few unique frames too?) before processing. If other parts of the video don't have all those duplicate frames you should leave out the TDecimate line.

[Marcio.ciconne]

That's the script I used. I encoded as 10 bit HEVC with Intel's QSV (GPU) encoder via ffmpeg. You might need to add more grain if you intend to encode with an 8 bit encoder.

Note that the short sample has lots of duplicate frames. I removed those (maybe a few unique frames too?) before processing. If other parts of the video don't have all those duplicate frames you should leave out the TDecimate line.

thank you very much friend
I will try to do this! 🤝🏻

[Marcio.ciconne]

AviSynth has filters for that:

LWLibavVideoSource("mp4.mp4") 
TDecimate(Cycle=5, CycleR=3) # remove duplicate frames
GradFun2db() # reduce posterization, alternate filter GradFun3()
ConvertBIts(10)
SMDegrain(thsad=100, tr=2, PreFilter=4) # temporal smooth a bit

You need to encode with a high bitrate and/or use a 10 bit encoder to keep them from coming back.

Friend, I can't download the SMDegrain filter, is there any other filter similar to it for this case?

[jagabo]

Try this one: https://github.com/Dogway/Avisynth-Scripts/tree/master/SMDegrain

Or you can use any mild, motion compensated temporal denoiser. like MCTemporalDenoise().

[Marcio.ciconne]

Try this one: https://github.com/Dogway/Avisynth-Scripts/tree/master/SMDegrain

Or you can use any mild, motion compensated temporal denoiser. like MCTemporalDenoise().

thanks