While searching in the registry I found the key "Noise Reduction" under
current_user\Software\Ati Technologies\Multimedia\Features\TV\Video for each source (TV tuner, Composite and S-video).
The parameter is not exposed with the other in the setup menus.
I tried to change it from the value of 0 up to 127.
I haven't noticed many differences in the output.
Does anyone know the meaning and range of this parameter ?

Thank in advance.
Riccardom