Hi guys,

Finished my 1080p master and upscaled it > UHD with Video Enhance AI.

The gamma seems to shift which is annoying as my 1080p master is the final result I want in terms of color grading.

Got some tips how to fix this with Hybrid Selur but as a 'noob' I am not able to figure it out myself. The instructions I've got are not 'complete' enough as they don't work (user error probably on my side).

This is my workflow
1. Upscale in VEAI 1080p > UHD and create an image sequence PNG (this files have a gamma shift which I want to fix to 'original 1080p master look' (input is Canon dslr 1080p rec 709 footage)
2. Open Hybrid Selur
3. Create image sequence with first and last frame of the upscaled PNG files. (luma range: TV and color matrix bt470bg, someone told to use this to combat the shift)
4. Output Prores 422 HQ
5. Avisynth filter gamma > 1,02 (this should fix the gamma shift?)
6. Avisynth custom code ConvertToYV12(matrix="Rec601")

With Avisynth I can't get any file out of hybrid with this error
p, li { white-space: pre-wrap; }
-> 2020-12-26@14_08_53_8910_02_video crashed: ERROR: C:\Users\nigel\Desktop\test ve\test v2_2020-12-26@14_08_53_8910_02.mov was not created!
Aborting '2020-12-26@14_08_53_8910_02_video' due to: ERROR: C:\Users\nigel\Desktop\test ve\test v2_2020-12-26@14_08_53_8910_02.mov was not created!

Somehow I managed to get a file out of hybrid but it was very low in size and couldn't play the file either. VLC crashed.

Not sure what I can do.


Another questions I would like to have answered. Since I plan to upscale 1080p > UHD. Should I skip sharpening on the 1080p timeline before upscaling? And only sharpen the UHD version if necessary? Or whats the best workflow here? Same for neat video noise reduction. Can I use this on my 1080p timeline before upscaling? Or should I do this on the upscaled version?


Notes I got earlier which didn't fix my problem unfortunately
Video Enhance AI shifts color pallete from Rec.601 -> Rec.709 when it is run with VIDEO (MP4) input to PNG output. It also lowers the gamma by factor of .02, i.e. 1.00->0.98.

You can shift it back by specifying the following in Hybrid when importing the png stream:

Selecting “bt470bg” for color matrix inserts ConvertToYV12(matrix="Rec601") into the Avisynth script, which corrects the colors.

To correct the gamma, select the Levels filter and change the gamma to 1.02.