Exactly 71.928 vs "sort of" 71.928

[sparktank]

So I've used this and I've used NVidia custom to get 71.928 for 23.946 (24/1.001) movies.

I have old Dell 1907FP that can do 60Hz or 75Hz on 1280x1024(maximum resolution).
Connected NVidia GeForce GTX 750ti (latest driver as of this post: 350.12) via HDMI-to-DVI(-Digital) cable.
I was able to create custom and run at 72.928Hz with no problem.

However, when I used madVR as the renderer in MPC-HC, it shows variable fluctuations between:
display 71.924xx Hz - 71.925xx Hz

I also have ReClock (v1885) installed and operating when I watch movies and RC shows a constant of:

Refresh Rate: 71.925 Hz (DDR)
Display: 1280x1024@72 (1/1)

Is this normal? I've read that values shift constantly as I've observed.
I mean for it be low as 71.924 as amdVR shows and 71.925 for ReClock.

I don't know what all the different settings mean. There's no real information I can find to see what effects what. Like I wouldn't know how to guess what different porch settings would effect how I get to 71.928 on my monitor.

Most "solutions" I see for getting 71.928 are for 1920x1080 monitors.

With Nvidia control panel, I see less settings than CRU (one less setting).
And if I use CRU, then I have to do some roundabout process chain to get it working. I can't remember but it wasn't fun. Something about interference from GeForce Experience (which I have uninstalled since).

ReClock adjusts videos from 23.976 to 24, so is this even a real problem if I get 71.925 instead of 71.928?

Any insight?

[ToastyX]

(04-25-2015 05:34 AM)sparktank Wrote:  So I've used this and I've used NVidia custom to get 71.928 for 23.946 (24/1.001) movies.

I have old Dell 1907FP that can do 60Hz or 75Hz on 1280x1024(maximum resolution).
Connected NVidia GeForce GTX 750ti (latest driver as of this post: 350.12) via HDMI-to-DVI(-Digital) cable.
I was able to create custom and run at 72.928Hz with no problem.

Have you checked if the monitor can actually run at 72 Hz? Many older monitors skip frames at anything other than 60 Hz: http://testufo.com/#test=frameskipping

(04-25-2015 05:34 AM)sparktank Wrote:  However, when I used madVR as the renderer in MPC-HC, it shows variable fluctuations between:
display 71.924xx Hz - 71.925xx Hz

I also have ReClock (v1885) installed and operating when I watch movies and RC shows a constant of:

Refresh Rate: 71.925 Hz (DDR)
Display: 1280x1024@72 (1/1)

Is this normal? I've read that values shift constantly as I've observed.
I mean for it be low as 71.924 as amdVR shows and 71.925 for ReClock.

I don't know what all the different settings mean. There's no real information I can find to see what effects what. Like I wouldn't know how to guess what different porch settings would effect how I get to 71.928 on my monitor.

The settings don't really affect anything. The actual refresh rate is the pixel clock ÷ horizontal total ÷ vertical total. The EDID can only store the pixel clock in MHz to two decimal places, and the hardware might have limitations that can affect the actual pixel clock rate, so that's what affects the ability to get exact refresh rates. One limitation is the horizontal values might be rounded to multiples of 8, and I don't know how precise the pixel clock can be controlled on different video cards.

I have a calculator that can figure out the pixel clock and totals needed to get a certain refresh rate: https://www.monitortests.com/pixelclock....=72&rate=1

The totals include the front porch + sync width + back porch, so you might have to reduce those values to reduce the totals. For best results, use multiples of 8 for horizontal values. Other than that, the values don't matter as long as the monitor can handle them.

(04-25-2015 05:34 AM)sparktank Wrote:  With Nvidia control panel, I see less settings than CRU (one less setting).

The blanking is the front porch + sync width + back porch, and the totals include the blanking, so the settings are the same either way.

(04-25-2015 05:34 AM)sparktank Wrote:  And if I use CRU, then I have to do some roundabout process chain to get it working. I can't remember but it wasn't fun. Something about interference from GeForce Experience (which I have uninstalled since).

With CRU 1.2, all you have to do is choose "Custom extension block" which is the same as importing blank-extension.dat before. You don't need to uninstall GeForce Experience.

(04-25-2015 05:34 AM)sparktank Wrote:  ReClock adjusts videos from 23.976 to 24, so is this even a real problem if I get 71.925 instead of 71.928?

ReClock is supposed to be able to adjust the frame rate based on the refresh rate, so it shouldn't matter if the actual refresh rate is slightly off. 24/23.976 FPS videos should play at 23.975 FPS at 71.925 Hz.

[sparktank]

Thanks for all the information!

Regarding the ufotest for frameskipping, I have to dig out a camera to check for sure.
So far, I've only been able to tell is if I use "SVP (Smooth Video Project)" to interpolate framerate to higher FPS.
When I try a full 1080p movie going at 3x the rate, madVR shows framedrops and delays.
Reducing the videos resolution to 800 width shows stability.
But, SVP is targeted at live-playback/manipulation.
An encoded video interpolated to 3x the FPS might reveal different results as the process is extensive for live-playback.

But the other information is very informative.
CRU 1.2 makes more sense now.

I'll check out the calculator and compare current settings and adjust.

That's comforting about RC.
When I watch movies in native format in original 1920x1080, I don't see as much judder than if I were to watch it on a 60Hz monitor.
When I interpolate to double the FPS and reduce video resolution to 1280x????, it's much more smoother and madVR doesn't reveal any drops.