I'll add the feature to --vpp-tweak in the next release, adding new option "swapuv".

Thank you very much Rigaya!

The uvswap feature has been added to --vpp-tweak in NVEnc 5.16.

Hello Rigaya!

I tried out the swap UV option.

I used this : --vpp-tweak swapuv=true
But the colors remained the same on my YV12 videos. :-(

same here, doesn't seem like swapuv is doing anything aside from changing the encoder output message
without: tweak: brightness 0.00, contrast 1.00, saturation 1.00, gamma 1.00, hue 0.00
with: tweak: brightness 0.00, contrast 1.00, saturation 1.00, gamma 1.00, hue 0.00, swapuv
call I used was:

NVEncC64 --avhw  -i "F:\TestClips&Co\files\file_1.mp4" --fps 25.000 --codec h265 --profile main10 --level auto --tier high --sar 1:1 --lookahead 16 --output-depth 10 --vbrhq 0 --vbr-quality 23.00 --max-bitrate 240000 --aq --aq-strength 5 --gop-len 240 --ref 7 --multiref-l0 7 --multiref-l1 7 --nonrefp --bframes 0 --no-b-adapt --mv-precision Q-pel --preset default --colormatrix bt470bg --vpp-resize default --output-res 640x352 --vpp-gauss disabled --vpp-tweak brightness=0,contrast=1,gamma=1,saturation=1,hue=0,swapuv=true/false --cuda-schedule sync --output "E:\Temp\file_1_2020-11-09@16_16_07_1210_01.265

Thanks for letting me know about this, I've fixed this in NVEnc 5.20.