FPS and LCD refresh rate

[behded]

Hi, I have long been wondering how a 29.97 fps video is actually displayed on a 60hz LCD?
Does 29.97fps mean the software video player will write/update the video memory 29.97 times every seocnd? But the video card will read the video memory 60 times a second and send it to the LCD?
Does it mean most of the video frames will be displayed twice and a few of them will be displayed 3 times?

[behded]

I have long been wondering how a 29.97 fps video is actually displayed on a 60hz LCD?
Does 29.97fps mean the software video player will write/update the video memory 29.97 times every seocnd? But the video card will read the video memory 60 times a second and send it to the LCD?
Does it mean most of the video frames will be displayed twice and a few of them will be displayed 3 times?

[foxyshadis]

No crossposting. >( Merged.

You're basically spot-on if vsync is implemented. If not, tearing everywhere based on decoding speed.

Reclock can change things to be a simple divisor of 60 (like 24 or 30) and sample the audio up just enough to take care of the difference, if that 1-in-1000 judder is too much.

[Delerue]

Yes, most of the video frames will be displayed twice. The monitor draws the same frame twice if your frame rate is 29.97 and the refresh rate 60 Hz, per example. The frame rate is something apart of the refresh rate. The RAMDAC controls the refresh rate, and the CPU/GPU controls the FPS. You can have 200 FPS and 60 Hz (you won't see more than 60 FPS, of course), or 100 Hz (if your monitor suports) and 20 FPS, per example.

As foxyshadis, if vsync is on the refresh rate will be synchronized with the FPS in such way that the FPS will never be higher than the refresh rate. This solve the 'break frames', but doesn't solve the jerky problem. Motion compensation (TrimensionDNM from WinDVD or Motion Morphing from Crystal Player) creates new frames between the original frames. So, increasing the frame rate you can reduce the jerky and have a smooth movimentation.