rany++at++netvision.net.il
Sat, 16 Nov 96 07:51:44 PST
>>
>> The deal is that when the room lights are running at one rate
>> and the video is running at another rate close to it, you
>> get beat frequencies that can be very upsetting.
>
>I would imagine this would occur only with flourescent light's, right?
>Incandescents probably don't have this problem. Or am I mistaken?
>
Sorry, but no. This (flickering at 50Hz) will happen with all lighting conditions
(even in the dark). The reason for that is that on current monitors, the decay time of
the monitor is fast enough, so that you see the "black" between fields. I would
suggest an interesting test :
1. Go to 72 Hz on a monitor that supports this frequency (/usr/gfx/setmon 72)
2. Stare on the screen for a while to get used.
3. Go to 60 Hz (/usr/gfx/setmon 60)
4. See how much 60Hz flickers
After doing that test I never work with 60Hz while developing.
In a system that we recently shipped, the frame rate was contracted to 25Hz.
Naturally, we thought of running the screens at 50Hz. Because of teh flickering we
changed that to 72Hz, updating at 24Hz, which is close enough to 50Hz. Ofcourse, this
has some problems too. Any update rate slower than the screen refresh rate will have
artifacts when moving fast across the screen.
__ | Ran Yakir
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