Noise reduction 'Auto' greyed out

[hf2019]

I own a Sony WF663 TV.

In the picture settings menu there is the "Noise reduction" option which has five levels: Auto, High, Medium, Low, Off.
The Auto option is always greyed out. I've tried all the 'Scene select' picture options as well as checking Freeview HD, Sky Q via hdmi as well as trying multiple in built apps.
Why is the Auto option never available and if I have to manually choose an option in what situations should I enable noise reduction and to what level.
Also this is different from another option labelled 'mpeg noise reduction' which has no Auto setting.
Thanks

[Pascale_F]

Hi hf2019, 

I'll see if I can find this out for you. Maybe someone else in the community can help in the meantime.

Thanks,

Pascale

[The_Black_Rose]

Hi hf2019,

That sounds a bit unusual, but, I think you may not be able to adjust all of the screen settings while the external devices are connected so can you disconnect Sky and check again?

Cheers,

The_Black_Rose

[hf2019]

Hi there.

I unplugged all HDMI cables and checked again but still the Auto option is greyed out. I've also compared the setting High with Off and can't see a difference in SD or HD. If I have to manually enable Noise Reduction when should it be used.

Thanks