GeDoSaTo Dynamic FPS Capping

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mynm
Posts: 40
Joined: 23 May 2015, 06:36

Re: GeDoSaTo Dynamic FPS Capping

Post by mynm » 09 Jun 2015, 06:56

Glide wrote:Looking at the Mirror's Edge example (because I own that game) I'd suggest that if you're sure that your display is 100% flicker-free, it may be response time issues on the LCD panel or simply the fact that 30 FPS is inadequate for the speed of motion with that high contrast scene.

If there's no flicker at all, 30 FPS at 60Hz should be identical to 30 FPS at 30Hz.

I will say that I did see judder when testing in the training sequence of Mirror's Edge at 30 FPS, but this got me to do some further investigating, and while my display does not use PWM, it turns out that there is a subtle flicker at 60Hz - which is enough to reduce persistence to about 12ms using this test.

I was able to detect this flicker using TFT Central's camera test where you take a photograph at a fixed shutter speed and see if there are any divisions in the line. At 1/30s there were two lines which are pure white, so the flicker frequency is 60Hz and not PWM. (and in other modes on the TV it flickers at 120/240Hz - again, not PWM)


Unless you're using a G-Sync display (and perhaps even then?) anything less than your refresh rate is generally going to be a bad experience for one reason or another.
Excuse me, I’m redoing proves (I did that proves 6 months ago), and I have a mistake, at 24fps 72hz, the LCD is only duplicating image. The CRT it’s true that is duplicating the image at 50fps 100hz, triplicating at 40fps 120hz or quadruplicating at 25fps 100hz.
I don’t know if LCDs duplicate image at 60fps 120hz, I don’t have one with 120hz.

At http://www.avsforum.com/forum/40-oled-t ... bling.html at the first page Nielo TM says that:
Unlike AM-LCDs, CRT and plasma show the same frame twice when inputting 30p. For an example, CRT and plasma display frame A for 16.7ms and again for 16.7ms. Between each cycle, there's a black period. AM-LCDs display the same frame for 33.3ms continuously, because it doesn't refresh. So the effect of double image is more tolerable/easy on the eye.
So if LCDs displays the same frame for 33.3ms continuously, the duplicated image may be caused by less response at 30fps or 30hz, or like you say because 30 FPS is inadequate for the speed of motion with that high contrast scene.

Glide
Posts: 280
Joined: 24 Mar 2015, 20:33

Re: GeDoSaTo Dynamic FPS Capping

Post by Glide » 09 Jun 2015, 07:03

mynm wrote:So if LCDs displays the same frame for 33.3ms continuously, the duplicated image may be caused by less response at 30fps or 30hz, or like you say because 30 FPS is inadequate for the speed of motion with that high contrast scene.
It is not held for 33.3ms
The screen is updated 60 times per second at 60Hz. (16.7ms)

The assumption is that displaying the same frame twice is identical to holding it for 33.3ms, but it seems that may only be true for a small number of displays.

mynm
Posts: 40
Joined: 23 May 2015, 06:36

Re: GeDoSaTo Dynamic FPS Capping

Post by mynm » 09 Jun 2015, 11:11

Glide wrote:The assumption is that displaying the same frame twice is identical to holding it for 33.3ms, but it seems that may only be true for a small number of displays.
So in a normal pwm free LCD or with the brightness at 100% (if at 100% is like pwm free), the blur masks the repeated images, and it looks like one blurred image?.

But is the image seen in LCDs with lightboost or similar like in a CRT?, Duplicated, triplicated, etc.

If I see duplicated images in my LDCs, do you think that it will be related with the fact that some LCDs (or all I don’t know) to pass for one color to other one has to go to black 0 and then to that color, or similar tings, I don’t know how exactly it works.

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