Automatically set the correct refresh rate

The video frequency setting on the ATV is for matching the ATV output to the TV's input. It does not relate to the content and there is no need to change it after a suitable flicker free picture is achieved with the ATV's menu screen.

You cannot do what you ask. The design assumes you will be viewing content in one format. I assume you're viewing both content formatted for US TV at 30 frames/sec, and other content formatted for 25 fps. When the video format and refresh do not agree, ATV has to use some tricks to make them match, dropping or holding frames. You'll just have to deal with it. You should be glad that your modern TV set allows this. Traditional sets were locked into one format.

You're welcome.

Cheers.

OK, so you watch Airport, a BBC program, so it's not surprising that is plays better on 50 Hz. To play it on 60 Hz, the ATV has to interpolate frames to make the video speed come out right (Scan conversion). You should recommend to Apple (http://www.apple.com/feedback/) that ATV should support owners with multi-format TVs (my US Samsung won't accept 50 Hz refresh rate) who wish to watch video from different regions using the optimum scan rate for each one. Until that happens, you may need to control it yourself. By the way, the content provided by Netflix is not offered by Apple, so you shouldn't blame Apple if Netflix lets you view programs you maybe should not be able to see. Anyway, you know the cause of the observed problem, and the feasible solution. As Vinceassociate has said, the video resolution setting is not viewed as a program-dependent parameter. You've just devised a novel way to use it.