(2012-06-15, 02:05)Plaguester Wrote: (2012-06-14, 16:34)Temar Wrote: For the effect to be visible on pans, you'd need a really fast pan. After all, the frame delay is only 1/120 of a second with a 60Hz refresh rate! So for the eye to actually notice it, the camera would have to move at least 1 foot in this 1/120 of a second so you could actually see a wobbling effect. This would equate to a camera movement of 120 foot/s or about 36m/s.
Um... no.
Um...yes. Do you even understand what happens when the player does a 3:2 pulldown? Just do the math yourself.
Quote:3:2 pulldown introduces awkward motion due to showing consecutive frames for differing amounts of time.
That's basically correct, but the effect can only be visible on very fast movements:
60 Hz / 24 FPS = 2.5
So basically the player would have to switch frames after 2.5 monitor frames. Though it's possible, noone will want that because of the tearing you get. So everybody turns on vsync. With vsync on the player will still display 2 movie-frames within 5 monitor-frames but one frame will be displayed for 3 monitor-frames and the other one for 2 monitor frames. Every second frame is therefore displayed half a monitor-frame longer than it should (3 monitor frames instead of 2.5), which happens to be (1/60)s/2 = 1/120s = 8.4ms.
If there is no movement between the two frames, you obviously will not notice the 3:2 pulldown at all. If there is movement you can notice it, but only if the camera moves very fast. That's because 8 ms is a very short time and you need to cover a lot of distance within this 8ms for your brain to actually notice that the object it is tracking should already be at a different position. Of course if you have such a scene, you will notice the judder. However these scenes are very rare and most of the people who claim to see a difference in normal day to day movies with slow pannings, would probably not pass in a blind test.
(2012-06-16, 17:21)skeeto2010 Wrote: Temar,
Here is a snippet of my debug log while trying to play 300 with the screen synching option on. You can see all the discontinuities that cause my judder. Any clues as to why the screen isn't switching to 24hz?
http://pastebin.com/EKTsJFgN
Or perhaps this is the audio struggling to sync up with the unstable video.
Your XBMC seems to try to switch the resolution:
Quote:10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: nvidia-settings -nt -q RefreshRate3 produced no output
But the command does not seem to return the expected output. Still it seems to have worked as randr reports a 24 Hz refresh rate:
Quote:10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Using RandR for refreshrate detection
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Detected refreshrate: 24 hertz
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Vblank counter has reset
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Detaching glX context
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Attaching glX context
10:08:46 T:2799651648 DEBUG: CVideoReferenceClock: Clock speed 100.100000%
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Received RandR event 124
10:08:46 T:2808044352 DEBUG: CVideoReferenceClock: Detected refreshrate: 24 hertz
Looks good to me. But I never configured it myself, so basically I don't know which settings XBMC expects to activate auto-switching. From your logfile however it seems to have worked fine.