The 120Hz Monitor Thread

[irR4tiOn4L]

Originally Posted by flu!d

So does adaptive vsync use any form of buffering or is it just basically a fps limiter?

Because I don't notice input lag as bad with adaptive vsync enabled (could just be a little placebo I suppose).

I would say it is only double buffered, not triple, because triple buffering needs a bit of voodoo to enable in most directx games. This means it doesn't address the lag problem like triple buffered vsync and basically acts like a frame limiter. It may also be the case that the lag profile changes when the framerate dips below the refresh rate, when it is basically off. Either way, unless you desperately hate tearing, the lag still means you're probably best with it off.

[Ogre]

Originally Posted by flu!d

So does adaptive vsync use any form of buffering or is it just basically a fps limiter?

Because I don't notice input lag as bad with adaptive vsync enabled (could just be a little placebo I suppose).

From my understanding Adaptive vsync, its just normal vsync while you are able to maintain the required frames.

But should you ever drop below the required frames, instead of having a massive drop in frames (Link) is disables vsync which should allow for a much smoother/unnoticeable drop in frames (Link) until you can get back to the required frame rate.

Hardocp do a good write up of it (Link)

[demowhc]

Originally Posted by squall_leonhart

No, because dropping from 120 to 100 implies triplebuffering in which the framerate is decoupled from the sync queue. The judder would only occur if it was 120 to 60 or 30 (due to double buffering)



Its not motion judder, thats a different situation entirely.

No. There is no triple buffering because first I have it off in CP and second I selected double buffering in game (see screenshots posted on the previous page). Thirdly, the frame rate does not change. Try it yourself, load up CSS and type fps_max 45 in console with vsync enabled. Not only will it sit at 45fps @ 60hz without dropping to 30, you will see that 45fps @ 60hz is not smooth and there is motion judder when panning/strafing.

Originally Posted by irR4tiOn4L

Ahh, no. You may be right on a finer granularity than halving. Probably right even.

But "motion judder" because of "being out of sync with the refresh rate"? Mate, that there is legalese if I ever saw some. It's nonsense with no discernible meaning.

Go ahead and explain what is this 'motion judder' and why it has to do with 'being out of sync with the refresh rate', while dropping suddenly from 60fps to 45fps because you are running Vsync has NOTHING to do with it.


Anyway, adaptive vsync and triple buffering adequately address this problem and in practice the judder is not that bad anyway. The real issue, as most everyone seems to agree, is input lag, which is only partially alleviated with triple buffering. I'd much rather just deal with tearing but enjoy the advance warning that comes with a sub 40ms response time.

Its motion judder with a steady and constant unchanging frame rate. If you have a steady 45fps on a 60hz display with vsync enabled, every 4th refresh is displaying the 3rd frame twice, what you are seeing is this:

frame1, frame2, frame3, frame3 - frame1, frame2, frame3, frame3 and so on.

The repeated frames are what gives motion judder, exactly the same as on TV's displaying 24fps material at 60hz using 2:3 pulldown.

Originally Posted by flu!d

So does adaptive vsync use any form of buffering or is it just basically a fps limiter?

Because I don't notice input lag as bad with adaptive vsync enabled (could just be a little placebo I suppose).

Adaptive vsync just disables vsync when your fps drop below your refresh rate. From what I can tell it is double buffered and there is input lag when vsync is engaged (when you have sufficient frame rate).

[flu!d]

The repeated frames are what gives motion judder, exactly the same as on TV's displaying 24fps material at 60hz using 2:3 pulldown.

The only issue here is that movie based material is filmed at 24fps, therefore ideally you would play it back at 24Hz for a judder free image, at 60 Hz you would use 2:3 pulldown and repeat a frame causing judder.

Game based material is not filmed as such, therefore there is no need for 2:3 pulldown, or any pulldown for than matter as frames are displayed as they are rendered.

Just my interpretation on the matter, having said that I'm no expert.

[squall_leonhart]

Originally Posted by irR4tiOn4L

I would say it is only double buffered, not triple, because triple buffering needs a bit of voodoo to enable in most directx games. This means it doesn't address the lag problem like triple buffered vsync and basically acts like a frame limiter. It may also be the case that the lag profile changes when the framerate dips below the refresh rate, when it is basically off. Either way, unless you desperately hate tearing, the lag still means you're probably best with it off.

Triplebuffering doesn't address lag at all (in D3D). this is a common error to think such, caused by several badly written anandtec articles

Originally Posted by demowhc

No. There is no triple buffering because first I have it off in CP and second I selected double buffering in game (see screenshots posted on the previous page). Thirdly, the frame rate does not change. Try it yourself, load up CSS and type fps_max 45 in console with vsync enabled. Not only will it sit at 45fps @ 60hz without dropping to 30, you will see that 45fps @ 60hz is not smooth and there is motion judder when panning/strafing.

1. NVCP triplebuffering does NOT affect Direct3D
2. Source based (CSS, HL2, CSGO, E.Y.E) all support Triplebuffering by default when vsync is enabled. Hence why any framerate set works. This used to not be the case, but since sometime 2010 the game has not required D3DOVerride to use a framecap of 58.

.

Its motion judder with a steady and constant unchanging frame rate. If you have a steady 45fps on a 60hz display with vsync enabled, every 4th refresh is displaying the 3rd frame twice, what you are seeing is this:

frame1, frame2, frame3, frame3 - frame1, frame2, frame3, frame3 and so on.

The repeated frames are what gives motion judder, exactly the same as on TV's displaying 24fps material at 60hz using 2:3 pulldown.

Video playback is very different to game playback. DirectX and OpenGL do not display duplicate frames, the Juddering is nothing to do with motion.

[demowhc]

Originally Posted by flu!d

The only issue here is that movie based material is filmed at 24fps, therefore ideally you would play it back at 24Hz for a judder free image, at 60 Hz you would use 2:3 pulldown and repeat a frame causing judder.

Game based material is not filmed as such, therefore there is no need for 2:3 pulldown, or any pulldown for than matter as frames are displayed as they are rendered.

Just my interpretation on the matter, having said that I'm no expert.

2:3 pull down is just that, 2 frames for every 3 refreshes. There are no TV's that run at 24hz, they run at multiples of 24hz, like 120 or 240hz.
At 120hz the frame is repeated 5 times in a row, then the next frame 5 times, so its consistent.

Originally Posted by squall_leonhart

1. NVCP triplebuffering does NOT affect Direct3D
2. Source based (CSS, HL2, CSGO, E.Y.E) all support Triplebuffering by default when vsync is enabled. Hence why any framerate set works. This used to not be the case, but since sometime 2010 the game has not required D3DOVerride to use a framecap of 58.

.




Video playback is very different to game playback. DirectX and OpenGL do not display duplicate frames, the Juddering is nothing to do with motion.

Dude, the option itself says double buffering within CS:GO, not only that, every other game follows the same behaviour, while having a steady frame rate.

No video playback is not different. The same rules apply.

[irR4tiOn4L]

Originally Posted by demowhc

Its motion judder with a steady and constant unchanging frame rate. If you have a steady 45fps on a 60hz display with vsync enabled, every 4th refresh is displaying the 3rd frame twice, what you are seeing is this:

frame1, frame2, frame3, frame3 - frame1, frame2, frame3, frame3 and so on.

The repeated frames are what gives motion judder, exactly the same as on TV's displaying 24fps material at 60hz using 2:3 pulldown.

We never talked about constant 45fps. We talked about a real framerate that shifts between 61fps and 59 fps, resulting in sudden jumps from 60fps to the next step down, lets say 45fps. Framerates hovering about the borderline do not feel smooth because of the jumps between steps, not motion judder. I don't know why you insist on diverting from that.

Compare the following:
Framerate - framerate with vsync
69 - 60
65 - 60
59 - 45
55 - 45
61 - 60
50 - 45
47 - 45
44 - 30
46 - 45
49 - 45
55 - 45
62 - 60

What should be plain from the above is that vsync is obviously less susceptible to framerate fluctuations, but when they do occur, they are much larger swings. While framerates are above the refresh rate, this does not occur, but once they drop below you get large, frequent jumps between framerates, which bothers a lot of people.

[squall_leonhart]

Dude, the option itself says double buffering within CS:GO, not only that, every other game follows the same behaviour, while having a steady frame rate.

CSGO is the only game so far which offers the option to select between double and triple buffering. CSS, which is the game you used in your previous example, forces triplebuffering.

However, since you changed your story and re-stated CSGO, i should tell you right now that CSGO does not honor the fps_max value. The lowest you can limit the framerate to is the current refresh rate. in my case any value below 60 will set the fps to 59.

No video playback is not different. The same rules apply.

No, the same rules do not apply. The api swap chains are designed in such a way to prevent any form of pulldown.

Originally Posted by irR4tiOn4L

We never talked about constant 45fps. We talked about a real framerate that shifts between 61fps and 59 fps, resulting in sudden jumps from 60fps to the next step down, lets say 45fps. Framerates hovering about the borderline do not feel smooth because of the jumps between steps, not motion judder. I don't know why you insist on diverting from that.

Compare the following:
Framerate - framerate with vsync
69 - 60
65 - 60
59 - 45
55 - 45
61 - 60
50 - 45
47 - 45
44 - 30
46 - 45
49 - 45
55 - 45
62 - 60

What should be plain from the above is that vsync is obviously less susceptible to framerate fluctuations, but when they do occur, they are much larger swings. While framerates are above the refresh rate, this does not occur, but once they drop below you get large, frequent jumps between framerates, which bothers a lot of people.

In reality, that 45fps is not true, its just a side effect of latency on the sample between two frames. very few games with a fps counter update quick enough to show the real frame rate

[flu!d]

2:3 pull down is just that, 2 frames for every 3 refreshes. There are no TV's that run at 24hz, they run at multiples of 24hz, like 120 or 240hz.
At 120hz the frame is repeated 5 times in a row, then the next frame 5 times, so its consistent.

?? When I select 24Hz on both my projector and my plasma they both report 24Hz, not 48Hz or 120Hz. Display devices that run motion flow type systems can run at a supposed 120Hz (or 100Hz for Australian devices), however I can't stand the effect and don't factor it into any of my purchases. If my display devices were actually running 120Hz I should be able to select 120Hz on the HTPC and I would expect the display devices to accept the setting, however I can assure you, they can't accept 120Hz or even 48Hz - I've tried.

But I fail to see why game based material would use any form of pulldown when frames are basically displayed as they are rendered, if frames are being rendered faster than they are being displayed than extra frame buffer is used, but frames are still being displayed in the exact order they were rendered?

Once again, I'm no expert, however I've been a HT enthusiast for many years now.

[demowhc]

Fluid, your TV is not running at 24hz, if it was it would be flickering. Yes it reports 24hz to show that its compatible with 24fps material input without pulldown. Its actually running at some multiple of 24, which is what you want.

Your projector on the other hand may very well be 24hz, but more than likely its using two refreshes per frame (48hz). Movie cinemas are the same, they play 24fps material at 48 or 72hz, by simply displaying each frame either 2 or 3 times in a row.

Thats right, your TV cannot accept 120hz input, but that has nothing to do with its output. Its taking 24fps material in, then on a 120hz TV its displaying each frame 5 times in a row. My TV's are the same, they report 24hz input (for bluray) but they are running at 120 or 240hz.

Originally Posted by irR4tiOn4L

We never talked about constant 45fps. We talked about a real framerate that shifts between 61fps and 59 fps, resulting in sudden jumps from 60fps to the next step down, lets say 45fps. .

Yes I know the drop and fluctuations in frame rate is especially annoying when using vsync without TB, but thats a seperate issue to what I am talking about. I said its possible to run at a steady frame rate below the refresh rate with vsync enabled that is not half the refresh rate (ie- 100fps solid at 120hz vsync without TB is possible), however I find motion is juddery.
I dont care what you were talking about, thats what I was talking about and you felt the need to (wrongly) correct me. I even posted screenshots for proof.

Originally Posted by squall_leonhart

CSGO is the only game so far which offers the option to select between double and triple buffering. CSS, which is the game you used in your previous example, forces triplebuffering.

However, since you changed your story and re-stated CSGO, i should tell you right now that CSGO does not honor the fps_max value. The lowest you can limit the framerate to is the current refresh rate. in my case any value below 60 will set the fps to 59.

No, the same rules do not apply. The api swap chains are designed in such a way to prevent any form of pulldown.

Thats simply not true and I didn't change any story. First of all, CS:GO does honor max fps commands. See my screenshots on the previous page. Secondly, the same behaviour is shown in every game I own, without TB activated. Frame rate does not have to drop to 30, its perfectly possible to run say 40 fps constant on a 60hz display without TB.


To be clear, so there's no more misunderstandings..

It is possible to run fps below the refresh rate with vsync enabled (ie 100fps @ 120hz & no TB) however the issue is motion is not smooth, even when using a frame cap and having a perfectly steady frame rate.

[demowhc]

Originally Posted by squall_leonhart

No, the same rules do not apply. The api swap chains are designed in such a way to prevent any form of pulldown.

If you cap your FPS to 24 on a 60hz display, you will have 2:3 pulldown. That simply means, the first frame is displayed across 2 refreshes, then the next frame is displayed across 3 refreshes, then 2, then 3, and so on, and will have uneven motion, that is associated with 2:3 pulldown.

If you use a 24fps cap on a 120hz display, each frame is displayed 5 refreshes in a row, and since its a consistent 5 refreshes per frame, motion looks smoother compared to 2:3 pulldown, which is why TV's and projectors use refresh rates that are multiples of 24, generally 48, 72, 96, 120 or 240. 120 and 240 being the most favoured for several reasons, but because they can also handle 30fps material without pulldown too.

[irR4tiOn4L]

Originally Posted by demowhc

I dont care what you were talking about, thats what I was talking about and you felt the need to (wrongly) correct me. I even posted screenshots for proof.

Ok, your point is noted. Framerates below the refresh rate produce 'motion judder' effects similar to running video at a framerate different to its native. It just adds to the general thrust of what is being said, which is that vysnc is simply not worth it, except as a frame cap. Btw, are you saying motion judder is present only with vsync at, say, constant 45fps?

Originally Posted by squall_leonhart

In reality, that 45fps is not true, its just a side effect of latency on the sample between two frames. very few games with a fps counter update quick enough to show the real frame rate

Are you sure? My impression was that the framerate really is 45fps, not "57 displayed as 45". This, I believe, is corroborated by the fact that vsync at 60hz is said to be smoother than say 200fps at 60hz, and that it results in lower gpu power consumption (indicating a lower use of the GPU).

So I was under the impression that 45fps with vsync really does mean 45fps, even if without vsync you might have gotten 57fps.

[demowhc]

You did (wrongly) correct me, heres your post:

Originally Posted by irR4tiOn4L

Ahh, no. You may be right on a finer granularity than halving. Probably right even.

But "motion judder" because of "being out of sync with the refresh rate"? Mate, that there is legalese if I ever saw some. It's nonsense with no discernible meaning.

Go ahead and explain what is this 'motion judder' and why it has to do with 'being out of sync with the refresh rate', while dropping suddenly from 60fps to 45fps because you are running Vsync has NOTHING to do with it.

Originally Posted by irR4tiOn4L

Ok, your point is noted. Framerates below the refresh rate produce 'motion judder' effects similar to running video at a framerate different to its native. It just adds to the general thrust of what is being said, which is that vysnc is simply not worth it, except as a frame cap. Btw, are you saying motion judder is present only with vsync at, say, constant 45fps?

Ok since you edited your post, ignore mine above

Yes I agree, vsync is not worth it unless you can maintain a frame rate at or above your refresh rate, and even then its no good for online gaming due to input lag. I use it for single player games thoguh, where a little latency doesnt matter.

As for motion judder, no its present at any frame rate below the refresh rate with vsync enabled, its just an unfortunate side effect of not having 1 frame per refresh and can't be avoided.

[flu!d]

Fluid, your TV is not running at 24hz, if it was it would be flickering. Yes it reports 24hz to show that its compatible with 24fps material input without pulldown. Its actually running at some multiple of 24, which is what you want.

Your projector on the other hand may very well be 24hz, but more than likely its using two refreshes per frame (48hz). Movie cinemas are the same, they play 24fps material at 48 or 72hz, by simply displaying each frame either 2 or 3 times in a row.

Unlike CRT (where phosphor decay, and therefore flicker was a bit of an issue at low refresh rates) LCD and plasma technologies are persistently lit display devices, therefore, technically, flicker shouldn't necessarily be an issue as each individual pixel remains lit until it is told to switch off - However, in the case of LCD especially (due to it's inherent lower response time in comparison to plasma, which isn't as bad in modern devices as it was in older devices) blurring in high speed pans may be an issue at a native, un-interpolated 24Hz refresh rate.

I think the biggest issue here is that very few low cost modern display devices display 24Hz material at 24Hz and use a multiple of 24Hz in order to overcome possible issues with such a low refresh rate - I'm fairly certain that my aging Hitachi Director Series plasma actually displays 24Hz at 24Hz, not too sure about my Epson the projector however. One thing I do know for certain though is that a quality display device using decent 2:3 pulldown to convert from 24p to 60p can actually do so with almost no discernible motion judder whatsoever.

However, HT discussion is for the AV forums, back to the topic at hand.

[demowhc]

You're right, LCD tech doesnt flicker, but it does have its own set of issues at low refresh rates. Plasma on the other hand does flicker. In both cases a refresh rate that is a multiple of 24 is used.

2:3 pulldown is the same on any display at 60hz.