Topic: The effect of forcing 120FPS on a 60Hz monitor

Referring to: http://www.svp-team.com/forum/viewtopic.php?id=1127

So, after hearing the alleged effect of what 120FPS does on 60Hz displays from the link above, I decided to give it a try. Well, it did absolutely nothing as to what the poster described it. 5 fps scenes are still converted to 10 fps and not to 60fps regardless.

But wait, if I use madVR's Smooth Motion along with forcing 120 FPS on 60Hz display, the perceived FPS of terrible-for-SVP scenes gets better. Jitter seems to be less, too! Proving its effect however, requires a high speed camera since madVR's Smooth Motion doesn't have an encoder version for me to encode and show. madVR Smooth Motion can only be enabled when the video is playing. It's not enabled when the video is paused, so you can't tell unless the video is playing, to see whatever trick it did.

I observed that the effect is akin to how digital audio filters require the audio source to be resampled to a higher sampling rate for a better output quality. madVR's frame blender (which is what Smooth Motion does) probably blended the frames to look smoother.

For my testing, I used this video, which I downloaded the 720p version to my hard disc first (a bit NSFW). 00:50~00:53 is an example of where the effect is prominent. https://www.youtube.com/watch?v=cYcfh12tIwo

Anyone could try out what I did? See if it worked for you? This is very close to placebo, I admit. I might have to seriously try an ABX test later. Setting it up is going to be a pain though.

2 Reply by Jeff R 1 (edited by Jeff R 1 31-12-2014 20:37:08)

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Re: The effect of forcing 120FPS on a 60Hz monitor

Here is a thread I started with a few answers.

http://www.svp-team.com/forum/viewtopic.php?id=2310

To sum up, HDMI can only do 60fps or refresh at that rate and that doesn't change.
If you force more frames per second, then it will be scaled to 60 fps or refreshed to that rate.
You can do what ever you want with SVP using what ever filters you apply and this may improve things like getting rid of artifacts, but in the end it will still be scaled to 60Hz refresh rate when sent to a 60Hz monitor.

3 Reply by Fanty1972 (edited by Fanty1972 01-01-2015 03:51:24)

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Re: The effect of forcing 120FPS on a 60Hz monitor

I wonder how 3D monitors work then.
I use a 3D Projector with a HDMI cable (buyed one, when I did not know about the limitations. The projector however could be aswell connected by a usual monitor cable.)
Its a 120Hz projector because it runs 3D material. 60FPS for each image. Capable of NVidia 3D "NVision", for 3D Gaming.

HOw is that possible?
Does it only use 30FPS per eye and interpolate it to 60FPS per eye (120FPS total) in the projector) or how does that work? I cant imagine that.... in gaming?

I usualy also watch 2D material with the 120Hz setting. But at 720p. If I use 1080p it claims a max of 60 FPS is possible for 1080p.

When I read various forums, people claim 720p would be possible @120Hz, but not 1080p because HDMI is limited by "pixels per second" and 1080p@120hz is too much pixels per second but 720p@120Hz is below the pixels per second maximum.

Other forums again claimed that yes... HDMI would be limited by "Pixels per Second" and may be able to do 120Hz but only if you hack some stuff?  hmm

Whatever... If it would be truth that HDMI can only trasnport 60FPS, then I possibly need to trash that cable and get me a 3m long monitor cable instead.

4 Reply by Jeff R 1 (edited by Jeff R 1 01-01-2015 07:32:13)

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Re: The effect of forcing 120FPS on a 60Hz monitor

OK, I'll take a stab at it and one of the developers can/may correct if they wish. Or you may if you like.  smile
If you were to take a 3D Blu-ray and create a file of it, it would (in most cases) exceed the 50GB max container of a disc. One of the easiest ways to make a copy of a 3D Blu-ray is to make a direct bit per bit ISO of it. Making an ISO of a 3D disc retains the part of the discs information to tell the display to play two separate movies running at the same time _ one for the left eye and one for the right.

When you play a 3D Blu-ray there are instructions on it (for a lack of a better term) that tell the display to divide up the picture into 2 separate movies, one for the left eye and one for the right to produce the 3D effect.
The display refreshes each picture (for the left and right eye) at 60Hz (or frames per second if you like), but this happens after it reaches the display.
However the signal from the player is still fed in through the HDMI cable at 60 Hz and the instructions with in the 3D disc tell the display to turn it into 3D by refreshing it at 120 Hz (60 Hz for each eye) or if you like at 240Hz for displays (projectors) that apply frame interpolation from with in the display.

5 Reply by Fanty1972 (edited by Fanty1972 01-01-2015 10:29:25)

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Re: The effect of forcing 120FPS on a 60Hz monitor

Hm. Would a VGA cable be able to deliver 120Hz material to the projector? (some cable must do it. Windows recognizes it as a 120hz device.

I just tested one that I have.. (was surprised that I have. Maybe it was delivered with the projector *scratch head*). (1,5m only... my High Speed (fast enough for 2160p video @ 60FPS) HDMI cable is 5m... thats about 80 Euros for a cable...  mad  ).... but it (VGA) flickers  sad
I googelt for VGA flickering... and it claims, that either the cable too long (1,5m is not too long I guess) or too bad shielded.

Problem is... it should be 5m minimum for my setup.
I also dont know if I saw a difference (except for flickering images when the picture was dark)

Hmm. So you think the 3D imagery is transportet es a 3840x1080 pixels  Full-SidebySide image @ 60FPS  (If I say, play world of warcraft in 3D on the projector) and broken up into two 1920x1080 pixels images inside the projector? Hmm.

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Re: The effect of forcing 120FPS on a 60Hz monitor

This is getting a bit out of my knowledge base as my projector is not 3D...

I don't believe 3D imagery is transported at a resolution of 3840x1080 pixels and we are talking about 1920 x 1080p here, that's 2K _ 4K is double that of course and requires a new HDMI cable.

3D is still 1920 x 1080p through the HDMI cable, the projector does the rest of the work turning it into 3D and upgrading the refresh rate to 120Hz.

Also remember that your projectors native resolution is 1920 x 1080p (assuming that), so even if a higher resolution was sent down the HDMI cable it will still be scaled down to your fixed native resolution.

About VGA : I don't know what the max resolution is for VGA or the max refresh rate it can handle _ you can look that up.
Check your specs on your projector though, I'm betting that the max refresh rate it can accept through VGA and HDMI is 60Hz at your maximum resolution of 1920 x 1080p. If you go beyond those specs, your projector will scale it down.

There is nothing to gain by ramping up the refresh rate or resolution _ even 4K is still 60 Hz refresh rate.

7 Reply by Fanty1972 (edited by Fanty1972 02-01-2015 03:45:39)

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Re: The effect of forcing 120FPS on a 60Hz monitor

Well, the projector doesnt use usual 3D as TVs do use. It uses Nvidia 3D technique, that requieres a Hardware in the PC and a quiet heavy and expensive (100 Euros) 3D Glasses.
Its not designed to watch 3D movies but to play real time 3D games with it. (through its usable with stereoscopic player+SVP) It only works with screens of minimum 100Hz.

I got that when buying a ASUS Gaming Laptop in 3D Edition, including 120Hz Display for the Nvidia 3D stuff. I buyed the projector because it said its Nvidia 3D compatible (wich are only few projectors)

the manual explains it like that:
The Graphic card renderes 2 frames (and it consumes 2 times as much hardware power to do that), one for each eye. It then switches those 2 frames 120 times per second and synchronises the shutter glasses with Infrared that comes out of the Laptops display top lid. (thats why I need to have the laptop below the wall I project on (of course with switched off display), I know pretty lame...)

The specs of the projector allow 120Hz at 720p and 60Hz at 1080Hz. (3D capable only at 720 because it needs 120hz for the 3D)

I usualy watch stuff at 720p to have 120Hz (and use SVP at "to screen refreshrate" wich is then 120Hz)....
Until yesterday, I was sure that 120Hz at 720p would be possible even for HDMI. After googling around yesterday I am not so sure anymore. (I more than once read HDMI is artificial (not by technical ability!) limited to 60Hz per channel (or something)

VGA is analog, it should have no "real" limitations at all (except for signal noise, red or blue color lines at the edges of things, flimmering and stuff like that, that do not exist in a digital transported image)
People used VGA to connect their old PC to 125hz CRT Displays in the stone ages allready.  lol

HDMI is digital and has a limited bandwich. So called "high speed HMDI" has bandwich enough for 4K movies @ 60Hz (wich in THEORY would mean fast enough for 1080p@ 240Hz. But indeed some sources I read yesterday claim that the HDMI standard is artificial limited to 60Hz, wich is possible to override with a hack or something. At least something I dont want to do...)

Meh...
I think I will try play around with the VGA a little more and compare it to the HDMI image, once I get back home...
And if I can see a diference in motion fluidity (wich I actually DO see on my laptop display), then.... f..off digital, welcome back analog. big_smile
But of course with a better shielded VGA cable.

EDIT:
Ok, now I read more into how that 3D stuff is working.

A 3D blue ray player does indeed send superframes through the cable (one image with both frames that is split at the destination). Like I guessed.
That projector that I own is NOT able to do that (it wont show 3D movies from 3D blue rays). It only suports computer 3D of NVidia wich works completely different.
That 3D does actually work that one frame for the left eye is send to the beamer and then another frame for the right eye is send throuh the beamer....

That sounds very very bad. Because that means, if HDMI is limited to 60FPS, a 3D movie could only play at 30FPS with that method. It would need VGA to be at 60FPS (because with this method it really needs to be fed with 120Hz)

But then I dont understand how I watched 3D movies, using HDMI, steroescopic player and SVP and had the usual smooth motion effect. (I also compared the smoothness with that splitscreen)

*readreadread* yeah it says, 3D signal must be fed with 720p120. Send as a sequence (1 frame left, 1 frame right etc) It uses a HDMI reciever chip that onyl accepts that 3D format. But... wft... wouldnt that mean it has a HDMI reciever chip that is capable of revieving 120 frames per second?

Bah, Why are things to confusing and no one ever tells someone whats going on.  roll

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Re: The effect of forcing 120FPS on a 60Hz monitor

What is the model of your projector and how old is it ?

9 Reply by Fanty1972 (edited by Fanty1972 02-01-2015 10:45:50)

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Re: The effect of forcing 120FPS on a 60Hz monitor

Jeff R 1 wrote:

What is the model of your projector and how old is it ?

very old. Its not build anymore.
the new model uses a common 3D model instead of that sequencing one.
In fact it wasnt even build anymore when I buyed it. But I did not want the follower model as its not compatible to NVidia 3D gaming anymore.

EDIT:
Ok, done lots of testing (and reading on the beamer)

In fact, I cant see a difference between Laptop Display (120Hz) and Projector with HDMI cable or Projector with VGA cable.
I can also clearly see a further improvement of "to refreshrate" (120Hz setting) compared to "to 1/2 refreshrate" at 120Hz setting. (Specially with one test video: http://youtu.be/vxIOUJ7by6U that recieves a huge amount of extra smoothing in the mountain range panning when set to 120Hz. The dance movement almost look identical in 60 or 120 FPS. The panning has visible differences) It looked in HDMI exactly identical to what it looked on the laptop or the VGA cable.

As for any "Official" proof that there may be something "special" to the HDMI reciever chip of that projector to be able to do 120Hz HMDI I only found several inofficial (review pages I never heard of) comments. One mentioned the chip that is build into that model is able to to it to be compatible to that "exotic" 3D of NVidia, that does need a 120 FPS feeding of image material to the projector/monitor. Another said, only projectors with the label "NVIdia 3D ready" are able to do this, because their HDMI reciever chips are tuned for this. A third mentioned that it can do this only to 720p material, as for 1080p the bandwich of the used HDMI is too low. The new model has a faster HDMI, that would be able to to it to 1080p too, but it lost NVidia 3D compatibility and by that 120hz ability.

And it seems a dead technology. As for the new models cant do it anymore but instead gained compatibility to the 3D standard that modern TVs and BLueRay players use. Uuhh..  roll  yikes

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Re: The effect of forcing 120FPS on a 60Hz monitor

Fanty1972
And it seems a dead technology. As for the new models cant do it anymore but instead gained compatibility to the 3D standard that modern TVs and BLueRay players use. Uuhh.. 

Look for DisplayPort-enabled projectors. It seems like DP itself has no real limitations.
As an example, ASUS 27-inch monitor accepts 2D up to 2560x1440 @144 Hz and 3D up to 2560x1440 @120 Hz.

11 Reply by Fanty1972 (edited by Fanty1972 03-01-2015 00:51:44)

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Re: The effect of forcing 120FPS on a 60Hz monitor

INteresting to know, once I need a new one.
I found another thing about 120Hz @HDMI.

And I finaly found OFFICIAL info on it. At the place I should have looked up 1.... the manuals ...  lol

The manual of the Laptop says about the HDMI port: HDMI 1.4 -  60Hz/120Hz output @1080p
The manual of the Projector says: HMDI: HDMI 1.3 - 60Hz input for 1080p and 120Hz Input for 720p

So, HDMI @ 120Hz does exist for real (and I dont need to buy a new cable).
Still leaves the question why Wikipedia claims ALL versions of HDMI are 60Hz only and in almost every forum everyone claims 120Hz is technically impossible with HDMI and suggest people to use VGA or DVI for 120Hz.

12 Reply by Nintendo Maniac 64 (edited by Nintendo Maniac 64 09-01-2015 23:09:56)

Re: The effect of forcing 120FPS on a 60Hz monitor

It's very simple - the official HDMI spec pre-v1.4 only went up to 60hz while v1.4 added 120hz for 3D.

The thing is though, HDMI uses the exact same video signal as DVI, so there's no technical reason you can't do something like 75hz or 90hz over HDMI.

A good example of this is the Oculus Rift DK2 which runs at 75hz natively and uses HDMI.


So there's a very easy solution to getting refresh rates other than 60hz and 120hz over HDMI  - custom resolutions.  Intel and Nvidia GPUs have this function in their control panels while AMD users can use CRU - Custom Resolution Utility.  I've used such a method to get wierd refresh rates like 77hz on my HDTV over HDMI (yes, the TV actually showed via its OSD that it was running at 77Hz).

Re: The effect of forcing 120FPS on a 60Hz monitor

This excellent idea is necessary just by the way

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Re: The effect of forcing 120FPS on a 60Hz monitor

Monitor overclocking is so dangerous.

I also attempted before, 120hz is unable on 60hz monitor.

Although I seted up well, That windows setting manager displays 120hz, but smoothness is  fall down.

60hz is more smooth than overclocked 120hz. and more natural.

15 Reply by James D (edited by James D 20-01-2015 22:05:09)

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Re: The effect of forcing 120FPS on a 60Hz monitor

It's better to overclock from 60 to 72 for 24fps video.

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Re: The effect of forcing 120FPS on a 60Hz monitor

James D
It's better to overclock from 60 to 72 or 24fps video.
Yeah, I'm using this trick. wink

Re: The effect of forcing 120FPS on a 60Hz monitor

I'm using a Trinitron CRT and there wasn't anyway to get above 85hz without the use of custom resolutions.  The thing is, CRTs only used the EDID as a guideline but flat panels and modern OSes use the EDID as the rule.

For reference, my monitor can go over 120hz at lower resolutions and can easily hit 90+Hz for your typical HD resolutions.

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Re: The effect of forcing 120FPS on a 60Hz monitor

Jeff R 1 wrote:

Here is a thread I started with a few answers.

http://www.svp-team.com/forum/viewtopic.php?id=2310

To sum up, HDMI can only do 60fps or refresh at that rate and that doesn't change.
If you force more frames per second, then it will be scaled to 60 fps or refreshed to that rate.
You can do what ever you want with SVP using what ever filters you apply and this may improve things like getting rid of artifacts, but in the end it will still be scaled to 60Hz refresh rate when sent to a 60Hz monitor.

Actually, there is more.... hdmi 2.0 stuff (videocard that supports hdmi 2.0 + hdmi 2.0 cable) can reproduce svp's 120hz in 1080p, or 4k60fps.. i have those... unfortunately my monitor is a 60hz 1080p 32'' tv kkkk... I'll try svp 120fps on a 60hz tv with v-sync on to see if there is difference...

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Re: The effect of forcing 120FPS on a 60Hz monitor

Roberto Rossi wrote:
Jeff R 1 wrote:

Here is a thread I started with a few answers.

http://www.svp-team.com/forum/viewtopic.php?id=2310

To sum up, HDMI can only do 60fps or refresh at that rate and that doesn't change.
If you force more frames per second, then it will be scaled to 60 fps or refreshed to that rate.
You can do what ever you want with SVP using what ever filters you apply and this may improve things like getting rid of artifacts, but in the end it will still be scaled to 60Hz refresh rate when sent to a 60Hz monitor.

Actually, there is more.... hdmi 2.0 stuff (videocard that supports hdmi 2.0 + hdmi 2.0 cable) can reproduce svp's 120hz in 1080p, or 4k60fps.. i have those... unfortunately my monitor is a 60hz 1080p 32'' tv kkkk... I'll try svp 120fps on a 60hz tv with v-sync on to see if there is difference...

My experience on seeing a 120fps/90fps/75fps movie with svp in a 60hz tv is negative, didn't like it! Nothing else to say. Better to stick with 60fps .... or buy a better monitor.

Re: The effect of forcing 120FPS on a 60Hz monitor

Roberto Rossi wrote:

My experience on seeing a 120fps/90fps/75fps movie with svp in a 60hz tv is negative, didn't like it! Nothing else to say. Better to stick with 60fps .... or buy a better monitor.

I agree, but I'm one of those few people that still use CRTs, so running my monitor at 90hz or higher is really easy.

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Re: The effect of forcing 120FPS on a 60Hz monitor

Nintendo Maniac 64 wrote:
Roberto Rossi wrote:

My experience on seeing a 120fps/90fps/75fps movie with svp in a 60hz tv is negative, didn't like it! Nothing else to say. Better to stick with 60fps .... or buy a better monitor.

I agree, but I'm one of those few people that still use CRTs, so running my monitor at 90hz or higher is really easy.

I'm tempted to dig out one of my ancient CRTs to test this, since I never "overdrove" them back in their day but I don't really have a way to drive them. 

What is setting SVP on 120 for a 60 Hz display supposed to accomplish?  For what I watch, SVP only fails to make motion fluid when the source media has many repeated frames sad