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NVIDIA's G-Sync Is VSync Designed For LCDs (not CRTs)
Phopojijo writes "A monitor redraws itself top to bottom because of how the electron guns in CRT monitors used to operate. VSync was created to align the completed frames, computed by a videocard, to the start of each monitor draw; without it, midway through a monitor's draw process, a break (horizontal tear) would be visible on screen between the two time-slices of animation. Pixels on LCD monitors do not need to wait for above lines of pixels to be drawn, but they do. G-Sync is a technology from NVIDIA to make monitor refresh rates variable. The monitor will time its draws to whenever the GPU is finished rendering. A scene which requires 40ms to draw will have a smooth 'framerate' of 25FPS instead of trying to fit in some fraction of 60 FPS."
NVIDIA also announced support for three 4k displays at the same time. That resolution would be 11520×2160.
Okay, can someone who isn't wrapped up in market-speak tell us what the practical benefit is here? The fact is that graphic cards are still designed around the concept of a frame; the rendering pipeline is based on that. 'vsync' doesn't have any meaning anymore; LCD monitors just ignore it and bitblt the next frame directly to the display without any delay. So this "G-sync" sounds to me like just a way to throttle the pipeline of the graphics card so it delivers a consistent FPS... which is something we can do since DirectX9.
So what, then, is the tangible benefit realized? Because I smell marketing, not technology, in this PR.
#fuckbeta #iamslashdot #dicemustdie
11520 = 3 x 3840
If _you_ had read the damn article, you would have noticed that the resolution is for THREE 4K monitors, side to side.
I'm not saying it's a graceful turn of phrase, or particularly clear, but most people would have been able to tell where he got it from...
No good deed goes unpunished...
Now we just wait until they finally figure out to employ a smarter protocol than sending the whole frame buffer over the wire when only a tiny part of the screen has changed. It would do wonders for APUs and other systems with shared memory.
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I would feel pretty good about this if it were being proposed as some sort of standard, but from the blurb, it looks like a single-vendor lock-in situation. You will need an Nvidia graphics card to make it work, but your monitor will also need an Nvidia circuit board to regulate the framerate. The only value of this kind of variable framerate technology is for gaming. This means that the needed circuitry will appear only in monitors that are meant specifically for gamers. This means that they will be segmented off from the larger LCD market, and probably priced for "the gamer who has everything". But then again, this kind of gamer can just buy some fancy 60Hz monitors and a graphics card that doesn't tear frames because it has enough power. The latter course is probably cheaper. I know that lots of PC gamers now use big LCD televisions as their desktop monitors, or multi-monitor setups. Somehow I don't see these people upgrading their monitors so that they can look decent even at lower framerates. They would just buy the sort of graphics card that doesn't give them lower framerates.
According to TFA, that's exactly what you'll be seeing.
This technology will be available soon on Kepler-based GeForce graphics cards but will require a monitor with support for G-Sync; not just any display will work. The first launch monitor is a variation on the very popular 144 Hz ASUS VG248QE 1920x1080 display
And
UPDATE 2: ASUS has announced the G-Sync enabled version of the VG248QE will be priced at $399.
So you're not far off there, either.
Considering the original version is priced at $280, that would put it closer to being 1.4x the cost of the original.
That's probably fair :) Though it's a little pricey but today's standards to begin with.
Interestingly, Nvidia will be providing the G-sync chips by themselves, allowing people to mod their monitor to install the chip on them. I'm not sure just how compatible this would be, but it might allow you to upgrade your existing monitors with G-sync support or get someone to do it for you, depending on your capabilities and willingness to risk your monitor.
For FPS's when you rotate all around, or for action movies where the camera moves quickly, all of the screen is updated.
Then make "scroll rectangle" one of the primitives in the screen difference protocol. If the camera turns, scroll the data in the frame buffer at the same speed that the camera turns. Sure, there'll be artifacts near the HUD, but overall, that should provide the illusion of less latency. MPEG-4 ASP (e.g. DivX, Xvid) uses this technique under the name "global motion compensation", but ultimately, the concept dates back to motion vectors way back in the H.261 era.
G-sync (i.e. sync originated by the graphics card) seems like a good idea.
It:
allows for the ability of single or multiple graphics cards within a computer to emulate genlock for multiple monitors, so that the refresh rates and refresh times of those monitors interact properly
allows for the synchronization of frame rendering and output, i.e. reducing display lag which is important for gamers and realtime applications.
allows for a graphics card to select the highest possible framerate (possibly under 60hz) when displaying higher resolutions (e.g. 4k or 8k) on cables/interfaces that don't allow for a full 60hz bitrate.
Good stuff.
I know that lots of PC gamers now use big LCD televisions as their desktop monitors
When did this come to be the case? A few years ago, people were telling me that almost nobody does that.
NVidia would have to change the whole industry for this
We can't have one of the largest purveyors of video hardware influencing display standards now, can we?
NVidia isn't some startup. They put GPUs into millions of devices; desktops, laptops, tablets, consoles, phones, etc. When they offer a new technique for syncing video the world is going to have a look. That doesn't mean it must be accepted, but it won't be dismissed out-of-hand.
Besides, given an advanced bus like DisplayPort I suspect this might amount to a simple video-chip-to-display negotiation with a transparent fallback. DisplayPort devices can be Ethernet peers, among other things; they can coordinate anything they wish. So promoting a display connection to a new syncing technique should be transparent and non-disruptive for all hardware, past and future, without some brand new interface standard.
Turns out that's exactly what is happening. From Anandtech:
Meanwhile we do have limited information on the interface itself; G-Sync is designed to work over DisplayPort (since it’s packet based), with NVIDIA manipulating the timing of the v-blank signal to indicate a refresh. Importantly, this indicates that NVIDIA may not be significantly modifying the DisplayPort protocol, which at least cracks open the door to other implementations on the source/video card side.
Maw! Fire up the karma burner!
Also, when you can have a gaming PC why would you ever want a glorified netbook with a laptop video card glued to it?
Because if you have more than one gamer in the household, you don't always want to have to buy two to four gaming PCs and two to four copies of each game. One console, one copy of each game, and two to four controllers are cheaper, even with console maker markup on the games. Even though console games are somewhat less likely to support same-screen multiplayer than they used to, I'm under the impression that console games are still more likely to support it than PC games. (And no, same-screen doesn't necessarily mean split-screen, especially for things like beat-em-ups, non-first-person shooters, and fighting games.)
G-Sync is still vsync, just at a variable rate that matches the rate that new pictures are available.
Well, the original VG248QE seems to be selling on Newegg for about $280. So they're talking about a retail price roughly 1.5x as much as the hardware they're basing it on.
It is pitch black. You are likely to be eaten by a grue.
It's over 9000!
(Oblig.)
Because skilled directors and camera operators have learned in the last 100 years of movie making history which kind of camera movements work, and painstakingly avoid those which don't work with low framerates.
Because of this: http://en.wikipedia.org/wiki/Motion_blur
If you freeze a movie frame shot at 24fps you'll see that moving objects are blurry. And in a fast pan it still looks anything but fluid.
I don't see anything about them selling chips to end users, just stuff about them selling upgrade modules. I guess each module will be specific to one make/model of monitor and will require cooperation of the monitor manufacturer to produce.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
Something the summary fails to point out is this will not work with existing LCD monitors. The monitors will have to have special hardware that supports G-Sync.
Standard LCD monitors and TVs update the pixels the same way old CRTs do. They start from the top and update line by line until they reach the bottom.
It is actually a little surprising they haven't done something like this for phone and laptop screens yet. The only thing that stopped them from doing it with the first LCDs was compatibility with existing video signals.
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Given how few CRT monitors there are in the wild (let alone on those computers that are running new hardware), I'm not sure why the CRT vs LCD distinction was noteworthy.
A tangent, but frankly, given the choice between 4K monitors that I couldn't afford an a return to widespread availability of a 16:10 option at 1920x1200, I'd take the latter. 16:9 is less ideal to me.
Not saying it doesn't make any difference, but why doesn't adding motion blur to a 24fps game look as good as a 120fps game?
File under 'M' for 'Manic ranting'
Because you have been trained by films for your entire life to think that blurry stuttery 24fps is smooth and cinematic. If you ever watch a movie where lots of action is happening on the screen at once, you'll probably get slightly lost because everything turns into an unrecognisable blur. For an example of this, watch any of the Michael Bay transformers movies and try to figure out which Transformer is on the scene during any random action shot.
Unfortunately upgrading to 60fps actually causes people to complain, because the action becomes so smooth that it feels cheap, like it was recorded on a camcorder. Yes this is retarded, but it's the truth.
I read the internet for the articles.
Input lag is how long a game takes to react on your manipulation of controls, not how long it takes to display it on the panel or CRT you're looking at. Maybe you mean output lag? Since screens get updated 50 or 60 times a second with TFTs and CRTs often get higher refresh rates, you're looking at 20ms or less for a screen refresh, when it comes to pure VSync delay. "Whoa dude, 20ms, my ping time is less than that!" I hear you say. Apart from the fact that most of the planet has ping times that are way higher, especially if you're playing global, this refresh frequency has been used for a reason. At about 20 frames per second, or 50ms, the human eye is no longer able to distinguish between individual pictures because it simply can't keep up with the data refresh rate. We do however still notice flicker and "less information" in the moving scene than we do in real life. At 50 or 60hz, the flicker is mostly gone, especially if we keep displaying the previous picture before we replace it with a new one. The "less information" thing is mostly gone too. Try a CRT at these refresh rates and you will most likely find that the picture may be worse (or even better if you have a proper CRT), but the lag you experience is gone.
Yes, that's right, it's gone with a CRT. Why is that? Because all these TFT screens you buy have a "scaler board" that reads all your inputs, converts the signals (even the digital ones) to a signal the display drivers understands and scales resolutions, color information and refresh rate to the native format of the panel.To do so, it buffers input signal for a few frames, does DSP stuff on it to get things like "dynamic contrast" and "color balance" adjusted, up- or downscale frame rate and such. This is the lag you are experiencing. if you have a delay of 3 frames at 50Hz you get a 60ms delay after the video has left your video card before it's displayed. That's right, the difference between a slow uplink and a fast uplink is often less critical than what sort of display you are using. Want to frag all those lagtards? Get a CRT and live next to an international internet exchange. You'll get up to 100ms on them. Not bad if you consider that the average time humans need to react is double that. ;)
I was promised a flying car. Where is my flying car?
Actually, the problem is even bigger. Somewhere around 200fps, you start flying into "uncanny valley" territory. 200fps is faster than your foveal cones can sense motion, but it's still less than half the framerate at which your peripheral rod can discern motion involving high-contrast content. When it comes to frame-based video, Nyquist makes a HUGE mess thanks to all the higher-order information conveyed by things like motion-blur. That's why so many people think 24fps somehow looks "natural", but 120fps looks "fake". Motion-blurred 24fps video has higher-order artifacts that can be discerned by BOTH the rods AND cones equally. It's "fake", but at least it's "consistent". 120fps video looks flawless and smooth to the cones in your fovea, but still has motion artifacts as far as your peripheral rods are concerned. Your brain notices, and screams, "Fake!"
Almost spilled my coffee there, NVidia and VSync in the same sentence? The nVidia linux driver has tearing artifacts on video almost no matter what you do, it's ridiculous. VLC, Dragon player, Totem, all have obvious tearing. mplayer looks better if you disable compositing and turn off all but one monitor, but still has some tearing if you look closely. I just tried xbmc yesterday, and it may be good.
Anyway, "GSync" seems like a good idea. Seems nice for videos with different refresh rates, like displaying 50 fps and 60 fps videos on the same monitor. If this fixed tearing, that would easily be worth $100 to me. For games i'm not sure if I'd prefer a variable frame rate to a consistent low framerate. Would make it obvious when the GPU is doing work, but maybe that's what NVidia wants. Also, it's good that they're not pitching it as a bandwidth saver, because it's not! It should be able to operate at the max frame rate consistently.
There needs to be a fps ceiling, due to limitations of the monitor hardware. I hope this doesn't introduce tearing anyway. Maybe the drawing function could block
Hello,
Here's a high speed video of an LCD refreshing:
http://www.youtube.com/watch?v=hD5gjAs1A2s
This includes regular LCD refreshing modes, as well as motion-blur-eliminating LightBoost strobe backlight modes (that allows LCD to have less motion blur than some CRT's).
Mark Rejhon
Chief Blur Buster
High speed video of an LCD refresh occuring in real-time:
http://www.youtube.com/watch?v=hD5gjAs1A2s
Also, input lag is the whole chain, INCLUDING how long it takes to display.
See AnandTech's article:
http://www.anandtech.com/show/2803/7
CRT's are only zero input lag at the top edge of the screen.
CRT's even have input lag for the bottom edge of the screen, because they have a finite frame transmission time (scanning from top to bottom).
Some gaming LCD's (certain BENQ and ASUS gaming LCD's) are the same way; they scan the pixels top to bottom in real time too (as seen in high speed video).
We're talking about input lag from game engine to human eyeballs, so it WILL also include frame transmission time (From computer to display), including any display mechanisms (scanout). nVidia G-Sync solves the problem by using ultrafast frame transmission times (1/144sec, even when running at 60Hz, since G-Sync uses a dotclock for frame transmission/scanout times of 1/144sec) -- they clearly explained it in their video.
Now, strobing does add a minor input lag, but an average of less than one frame. (For LCD's with less motion blur than CRT"s, google "lightboost" -- John Carmack said he uses a LightBoost monitor)
>Pixels on LCD monitors do not need to wait for above lines of pixels to be drawn, but they do.
but they do!
Who logs in to gdm? Not I, said the duck.
because games use shitty motion blur effects
there is a difference between shitty simulation of motion blur, and a real thing recorded with a camera
Who logs in to gdm? Not I, said the duck.
I've been expecting this ever since we brought out DVI-D and then HDMI and Display Port. I'm in fact a little shocked its taken this long. Its really a simple concept; when the frame buffer is ready to be drawn, tell the monitor to refresh with that data, then work on the next frame. In fact, that's exactly how people think video output works already in most cases, but its not.
- Michael T. Babcock (Yes, I blog)
You mean this quote? "Initially supporting Asus’s VG248QE monitor, end-users will be able to mod their monitor to install the board, or alternatively professional modders will be selling pre-modified monitors."
- Michael T. Babcock (Yes, I blog)
I've never met anyone who thought 120fps motion looked fake. I've heard them say it looks un-movie-like but not fake.
Run a 120fps video of a landscape on a picture frame and it looks a lot like a window, it does not look like a movie, but it does look real.
- Michael T. Babcock (Yes, I blog)
Sit closer, so the screen completely fills your field of vision and immerses you in the image. Your opinion will probably change.
If you sit back from the screen, you're using foveal cones to watch it. It's the rods along your vision field's periphery that cause the problems.
The "uncanny valley" problem affects mainly immersive videogames where you're either sitting really close to the screen, or have additional screens off to the side that are viewed mainly with peripheral vision.
This is a problem people involved with immersive virtual reality have known about for a LONG time. If you put somebody into a virtual-reality world feeling like he's wearing a motorcycle helmet that only allows him to look straight ahead, he finds the constraints to be annoying, but describes what he sees as "amazingly lifelike". As you widen his field of vision, the constraints annoy him less, but the experience itself deteriorates and feels increasingly creepy. At its most extreme, you get this overwhelming feeling that there's "something" off to the side, just outside your field of vision, that you can't get a good look at, but nevertheless presents danger to you. I've experienced it, and it really does become scary after a while.
In the most extreme case -- sensitive individual, searingly-white (or green) dot against completely black background near the edge of one's peripheral vision with dark-adapted rods, you have to get the effective flicker rate up above 500-800hz to eliminate it completely. And even then, nobody really knows yet whether that's truly high enough, because displays capable of that kind of refresh rate don't exist yet, and the experiments have all been done with pulsing lasers.
To get to THIS level, we're going to need OLED displays where every row (if not every pixel cluster, or even every subpixel element) requires its own dedicated PWM controller and local sample buffer. And that's why this article is such good news... it's the first step towards GETTING to the point where the individual elements can have their own local driver circuits.
I already spend most of my video watching time in front of a 103" DLP projection screen at 10' ... and I prefer IMAX high frame rate to low frame rate films because the jitter drives me nuts on lower frame rates.
- Michael T. Babcock (Yes, I blog)
Actually, Gabe Newell at last year's CES (last January) was talking about NVIDIA Maxwell architecture. He claims NVIDIA will allow GPU virtualization for gaming applications. In other words, one PC could power multiple netbooks or Roku-style Steam boxes.
That said, split-screen (even multi-monitor "split-screen") is cool and occasionally occurs in PC games.