VESA have this week announced their new ‘ClearMR’ certification scheme for displays, designed to offer a certification process, badge and performance tiers that will (according to VESA at least) give customers more clarity and transparency on motion blur performance when selecting a new display, whether it’s a monitor, TV, phone, tablet, laptop or other device. It applies to LCD and OLED displays in the monitor market which is what we are primarily interested in, and we wanted to break down what this new scheme is about, how it’s tested and what our thoughts are on it at this early stage. This isn’t going to be another re-hash of the press release as you will have no doubt seen online already, it’s all the information we could find on the scheme and our thoughts on its value.
What influences motion blur and clarity on a display?
Monitor motion clarity and blur is influenced by several factors including pixel response times, overshoot levels, panel refresh rate (a big factor), display type and whether or not additional “motion blur reduction” techniques are added to the display. These might include familiar strobing blur reduction backlights on LCD displays like ULMB, ELMB and the likes. On OLED displays Black Frame Insertion (BFI) is the common alternative.
Generally the quicker the response times, the lower the overshoot and the higher the refresh rate – the better the display will be when it comes to motion clarity and blur levels. The additional blur reduction methods mentioned here can help overcome remaining limitations with a “sample and hold” technology like this and help improve the perceived motion blur for the user. That’s explained in a lot more detail in our article about motion blur reduction backlights if you want to know more.
With all that in mind, let’s take a look at the new ClearMR scheme and performance tiers:
How ClearMR is defined and the performance tiers
The new metric “Clear Motion Ratio” (CMR) that VESA have created aims to provide a simple numerical value which is based on the ratio of clear pixels to blurry pixels in a moving image. This is designed to allow consumers to easily compare the amount of motion blur between VESA Certified ClearMR displays and select one appropriate to their requirements. That’s the theory anyway.
Certified displays will earn the ClearMR badge and logo, along with a ClearMR rating tier.
The VESA Certified ClearMR logo features multiple performance tiers from ClearMR 3000 at the bottom end, up to ClearMR 9000 at the top end. Each is supposed to represent a range of blur performance based on the ratio of clear pixels to blurry pixels as a percentage. As an example, the ClearMR 7000 tier defined as a CMR range of 65 – 75 times (6500 to 7500 percent) more clear pixels than blurry pixels. Put another way, this means the display would have a clear-to-blurry ratio of 65–75:1 or 65 – 75 times more clear pixels than blurry ones. Clear? No, not particularly.
In an interview with Ars Technica, Dale Stolitzka, senior principal researcher at Samsung Display’s America R&D Lab and lead contributor to ClearMR, said that VESA settled on ClearMR 3000 as the lowest tier befitting displays in the 90–120 Hz range. Displays that are 60Hz would typically not qualify for ClearMR certification apparently at all. ClearMR 9000 is the current top tier and represents the best performance.
VESA say that each tier provides a visually distinguishable change in clarity, with higher CMR numbers indicating higher image quality and less blur. In the simplest form, the idea is that a screen would carry the certification and logo, and then the higher the number on the tier, the better when it comes to motion blur. That’s good so far, and makes the comparisons and selection simpler for the consumer.
Only displays that pass all ClearMR compliance tests can qualify for the VESA Certified ClearMR logo which of course means display manufacturers have to pay to get their display certified at an approved test centre, which means there’s a charge for this scheme and money coming in to VESA for the certification.
Trying to replace G2G and MPRT specs and the problems with these legacy measurements
VESA’s aim with this new scheme is to try and usurp the long standing metrics used in the industry to articulate motion handling. Primarily those are G2G (grey to grey) response times, and in more recent years, sometimes MPRT (Moving Picture Response Time). As VESA put it in their marketing material: “CMR replaces Motion Picture Response Time (MPRT) and other methods of blur characterization since these other metrics do not accurately reflect the true nature of blur. Current methods, such as MPRT, fail to reflect the true nature of blur because a solely time-based metric cannot account for a number of image enhancement and blur mitigation techniques, such as excessive overshoot and undershoot, which can create artifacts and distortions that negatively impact image quality.”
This is a good idea and we welcome any approach that can help articulate performance in a more meaningful way for consumers. Everyone is surely wary now of quoted G2G response times which mean very little in today’s market. Everything seems to be rated as 1ms G2G now (or lower), and there’s nowhere else left to go with this spec now. The problem is that the G2G spec figure has always been based on the “best case” measurement for the panel, and when independent testing is carried out by reviewers like ourselves, you find that the rest of the pixel transitions, or the average across a wider range of measurements is much different. The manufacturer rating is misleading when it’s a best case example cherry picked from an otherwise slower set of measurements.
The other issue with the G2G spec is that they are often based on entirely unrealistic test conditions or settings. For example commonly when using maximum overdrive modes on the screen that might achieve the desired 1ms figure (again in the best case example out of a wider range of slower figures), but only at the expense of excessive overshoot artefacts. This makes the setting generally totally unusable in practice, yet manufacturers continue to include these modes in order to reach smaller and smaller G2G figures. There’s nothing penalising the measurement when overshoot is present, so they continue to push it in that way a lot of the time.
G2G manufacturer specs cannot be trusted and instead it’s wise to rely on third party reviews and testing to confirm the real-world performance across a wider range of transitions, at sensible screen settings, when trying to decide if a screen is right for you, or how it compares to other models.
MPRT (Moving Picture Response Time) is just as bad as that’s really only useful as an indication that the screen includes a blur reduction backlight option. All the screens that feature this spec generally have the same 1ms MPRT spec again, making it all a bit pointless. You can read more about MPRT in our article here.
So with all this in mind, it’s obvious that the existing G2G and MPRT specs do need to be retired, and we need something else that tries to capture real-world experience and defines it for the consumer in a clear way. But is ClearMR the answer? Let’s look at how they are measuring this…
How performance is measured and why it’s anything but “Clear”
VESA explain the testing and certification approach as follows: “Products undergoing ClearMR certification are tested using a digital high-speed camera, which takes pictures of a test pattern moving across the screen as it changes from one frame to the next. A luminance measuring device, such as a colorimeter, is used to verify pattern luminance. The pictures are compiled into a profile and analyzed to provide a repeatable and objective CMR value.”
VESA provided some example test images which give an indication of the different levels of blur that would fall in to each tier along with the test images they are using. Images via artstechnica.com
They don’t provide any further specifics which means it is a bit of a mystery as to how this setup works, and makes it hard for manufacturers or the media to test themselves or verify the results. The only other thing VESA provide on their website is the table included below, which doesn’t really make any sense on its own without additional context and detail:
Arstechnica provided some additional information based on an interview with Dale Stolitzka from Samsung that “ClearMR testing includes measurements of a test pattern moving across the screen at 15 degrees per second, which Stolitzka said is about the amount of time it takes for an object to move across a screen in approximately four seconds.” This may of course be faster than some games, and slower than others, but is a reasonable place to start and use as a baseline for these purposes.
They also report that the test involves “a bar with different luminances [which] moves across a small box on the display and is measured with a camera at a fixed location equal to 1.5 times the height of the display being tested. Multiple frames are shot to create a composite image, providing an idea of what the user would see when blur moves across the screen.” This information apparently comes from Samsung so we will take it on good faith that it is accurate. The testing approach might leave some areas of potential concern if this approach is used. For instance this means that the camera position is much further away from the screen for a large display than it is for a small display, but that probably doesn’t represent a users viewing position, at least not for desktop monitors. In those situations the desk size and viewing distance tend to be fixed, but the screen size could vary. Hopefully it won’t matter too much as presumably this approach is designed to make it possible to capture images of a sensible size so they are clear. Screen resolution could also have an impact here, but we assume the process will be adapted for each display to be sensible.
In their press release and on their website then they also talk about various aspects of the testing setup and approach that we wanted to dissect a bit and discuss:
Products are tested at ambient room temperature after a warm-up period
Sensible, as a warm up period is certainly beneficial for any testing of displays. It’s not listed what that ambient temperature is but Arstechnica report (based on a conversation with Samsung) that it will be between 72.5° and 76° Fahrenheit apparently. How this would be controlled between test centres, and how long the warm-up period for the display is; but we will make an assumption that VESA and their testing centres will be doing this appropriately. This is a sensible start to the testing requirements.
Tested in the displays default setup
VESA say on their website that displays would be tested “in their default power-up configuration”. This means manufacturers will have to be extra careful about the default setup, factory calibration and default settings selected when their display ships. This is a good thing, as it should also mean that they need to put forward the optimal screen settings for certification, which in turn means when a consumer buys the screen the settings have been thought through and configured nicely. This should save the buyer time and effort.
There is however a potential gap here. What if the screen performs completely differently in other modes and at other settings, and what if those other settings are actually the more likely to be used? For instance what if you had a screen where the default overdrive mode at maximum refresh rate was optimal, but then that same mode was unusable for lower refresh rates or during VRR situations? This can happen quite a lot on adaptive-sync screens and is linked to what we will discuss below about the pitfalls of only testing at native res and max refresh rate too. There are other scenarios where the settings selected could well influence motion clarity in real use, so basing testing on a single default setup has risks.
Maximum refresh rate and native resolution
This is where we start to have real problems with the testing process.
This makes sense if you have to only choose one mode and one configuration of settings to test. However it doesn’t account for other scenarios such as lower refresh rate input devices, VRR situations or non-native resolutions. What about overclocked refresh rate modes, are those included? What if you had a 4K screen with 240Hz (yes, they do exist now – e.g. Samsung Odyssey Neo G8) and were playing an old console at 1080p 60Hz? What if you were PC gaming and had FreeSync or G-sync active and your frame rate and refresh rate was fluctuating much lower than the native refresh rate?
Testing only at native resolution and maximum refresh rate only tells you one possible scenario, but your actual usage and performance may vary massively in real use. This is why we test things like response times (with gamma corrected G2G and overshoot measurements) at a range of frame rates and refresh rates across VRR, and in a range of settings and modes; as well as for fixed settings like max refresh rate. The ClearMR process and subsequent rating is really only relevant for a single, niche gaming / motion blur use case. You’ve got to start somewhere obviously, and this is as good a place as any, but it doesn’t tell the full story when it comes to screen performance or motion blur expectations. Basing a screen’s rating and performance tier on this one specific scenario is very limited.
Undefined limits are in place for overshoot
VESA say that “limits are also placed on overshoot and undershoot during product testing so that the overall visual performance is not compromised in an effort to reach a specific numerical target.” That’s a positive thing, as we don’t need manufacturers tricking their way to a good rating by having unusable modes with massive amounts of overshoot like they do today to fiddle super-low G2G specs. However, it’s not clear what these “limits” are from VESA.
Our concern here is that when they introduced the VESA “AdaptiveSync” certification scheme (not to be confused with adaptive-sync as a general display/graphics card capability) they defined response time and overshoot testing methods at that time which we (and others) did not agree with, and which we feel do not represent the fairest or most real-world view of performance. You can read our linked article for more information on that.
We can only assume that the same overshoot testing approach and thresholds will be applied here for ClearMR testing given it’s the same organisation, and the schemes are being launched only a few months apart which then leads to concerns here for the ClearMR process.
In the VESA ‘AdaptiveSync’ spec the overshoot (on transitions from dark to light shades) needs to be less than or equal to 20%, or for undershoot (transitions from light to dark shades) needs to be less than or equal to 15% in their tests. There’s several problems with this in our opinion. These are in our opinion too high values and leaves the door open for certification under both the AdaptiveSync and ClearMR programmes (assuming ClearMR use the same criteria) which is supposed to only allow low overshoot errors, when a screen might still have very noticeable and distracting overshoot in practice. 20%+ overshoot in our testing has always been considered “red” on our tables and definitely represents visual and obvious overshoot artefacts. If a screen can pass certification with 19.9% overshoot, that’s still giving manufacturers chance to fiddle the process with a setting where actually the overshoot is far too noticeable and problematic to use in real life.
We would argue that anything above 15% is a real problem so at the very least we believe the overshoot in this new testing criteria should be capped to that same 15% as the undershoot. Even that though we would consider to be “bad” overshoot and marked as red on our heatmaps for these measurements, and if you were really trying to limit this for testing and certification to something that is a sensible level of overshoot, it should be a lower value like 10% maximum we think.
Additionally, why is it ok to have 20% on the rise times where light halos would appear and only 15% on the fall times where dark halos appear? If you want to actually make the certification more meaningful when it comes to representing “low overshoot”, it should really be 10% or lower for BOTH.
There is another problem with the overshoot measurement approach they are adopting and that is that using any % is flawed. Using any % for an overshoot calculation is not always reflective of real-world perceived visual artefacts, and is a moving number dependent on the range of the transition. We talked about this a lot more in this article if you want to know more about why using a % overshoot is flawed, but we have since moved to a far more meaningful and reliable RGB value overshoot for our testing. A percentage just doesn’t really make sense and is a legacy approach. We’d love to see VESA take this in to account and move away from % as well as tightening up what it considers an acceptable overshoot and undershoot.
At the time of the AdaptiveSync launch we also picked up on the following within their FAQ:
For the G2G overshoot/undershoot tests, are you testing at one refresh rate or multiple refresh rates?https://www.adaptivesync.org/faq/
When running in Adaptive-Sync mode, the refresh rate (i.e., the speed at which the data is transferred, frame by frame, to the display) and the speed at which the display scan out is occurring is always at maximum refresh rate. When frames are being updated at less than the maximum refresh rate of the panel, this is not because the panel is running any slower, but because the vertical blanking interval (VBlank) timing between frame to frame has increased. Therefore, there is no reason to test G2G/Overshoot/Undershoot at anything other than maximum refresh rate as that’s the only rate the panel will be operating at when in Adaptive-Sync mode. If you were to exit from Adaptive-Sync mode and change the display timing to a fixed rate timing, then and only then does the display clock rate and scan-out time change, at which point different G2G performance may occur. However, this is outside of the Adaptive-Sync mode and not included within the VESA Adaptive-Sync Display test.
We have an issue with this. This is not what is experienced in real usage in many cases, you will often see G2G figures and especially overshoot levels vary depending on the active frame rate within a VRR situation. True, some adaptive-sync displays have a fixed G2G figure across the range, but if that is the case then the overshoot level will increase as the refresh rate lowers. That’s one of the reasons why NVIDIA developed technologies like “variable overdrive” for G-sync module screens, and why some manufacturers like Asus also develop this technology separately for adaptive-sync screens. That deliberately slows G2G response times as refresh rate lowers in order to control overshoot. There is varying performance in VRR situations across the VRR range on these screens, it is a bit strange how VESA claim there isn’t.
This bit is really an aside as for ClearMR they are only testing at a fixed maximum refresh rate anyway, not during VRR. It just doesn’t fill us with confidence around the testing approach and criteria when statements like this are made.
Motion blur reduction modes and backlight strobing are DISABLED for testing
Why?! If a screen adds a good and very usable motion blur reduction mode, why should it be penalised and count for nothing? Why would that screen potentially receive the same rating for motion blur as a similar screen without it? These motion blur reduction modes are specifically designed to….well, reduce motion blur. Why are they not being considered within the certification process? VESA say that the “ClearMR standard and logo program limits the use of these enhancement techniques during testing—enabling consumers to make a fair comparison of motion blur quality across VESA Certified ClearMR display products.” They also say “Backlight strobing is disabled during testing in order to establish a level playing field and prevent unfair comparisons with products that do not utilize those blur reduction methods”. But in our opinion that isn’t fair at all. Why are manufacturers who spend time and money adding useful modes like this being penalised just to make it “fair” with another manufacturer who didn’t bother?
Samsung and LG are already on board
VESA certification and logo programs are established with the contributions of more than three hundred VESA member companies, including major OEMs that supply displays, graphic cards, CPUs, panels, display drivers and other components. Already we know from the ClearMR press release that Samsung and LG were involved in the production of this scheme, which of course means it isn’t very “independent” at all. Here’s what some of their representatives had to say about the new scheme:
“With ClearMR, VESA is providing the electronics industry with an open standard that gives consumers the confidence in knowing that they are purchasing a TV, notebook or monitor that meets the most well-defined set of blur criteria,” said Dale Stolitzka, senior principal researcher at Samsung Display’s America R&D Lab and lead contributor to ClearMR. “Backing VESA’s ClearMR standard with a logo program will enable buyers to feel confident that they’re getting a display with the clearest depiction of action for the utmost in viewing pleasure.”
“Samsung Display has no doubt that consumers will have a much easier time in selecting their TVs, monitors and laptop displays now that the display industry has coalesced around a more exacting quantification of motion blur,” stated Hojung Lee, vice president and head of Mobile Display Product Planning Team at Samsung Display. “We applaud VESA’s global standardization of the Clear Motion Ratio metric in ClearMR, a specification for blur-free viewing that we fully support, and to which we have already certified our newest OLED display.”
According to Seok-ho Jang, vice president and head of the IT development division of LG Electronics (LG), “We believe that with VESA launching its ClearMR standard in the rapidly growing gaming market, we can expect to see even greater innovation in the gaming monitor categories. We are proud that the LG UltraGear™ brand will be involved from the very beginning with the acclaimed LG UltraGear™ 48GQ900, 32GQ850 and 27GP850 models, the first monitors to receive certification in the VESA Certified ClearMR logo program through a VESA authorized test center. LG will continue to collaborate with VESA to ensure that our monitors not only meet the high standards demanded by VESA’s performance tests, but are also well equipped to satisfy the expectations and diverse needs of today’s consumers.”
Which screens are certified so far?
We can learn more about this scheme and some of the pitfalls by looking at the current list of certified displays. At the moment there are 14 models listed, although some of them appear to be regional variations of the same screen. We went through them all and added the technology type (LCD vs OLED) and the refresh rate which is one of the biggest influencers for motion clarity.
Immediately you can see some problems with the tiers and their approach. How is a 260Hz refresh rate LCD in the same tier as a 165Hz model for instance (both in Tier 7000)? Is a 138Hz OLED really the same as a 165Hz IPS LCD (again both in Tier 7000). Part of the problem might be that the tiers are quite wide in their range (a difference of 1000 is allowed in the ratio), or maybe some of this is down to the flawed testing approach of limited scope. Some of this categorization definitely raises alarm bells.
HDR display performance is coming later
One final note about HDR displays. VESA say that “the ClearMR specification and logo program can be used with high dynamic range (HDR) products; however, the current version of the specification requires products to be tested in standard dynamic range (SDR) mode for certification. VESA is currently working on an update to ClearMR that will enable testing in HDR mode, which will be released in the future.”
We don’t know what that may entail but hopefully it extends beyond simply running the screen in HDR10 input mode and accounts for things like the speed of backlight dimming as an example. That can impact the response times of a panel for instance, and proper FALD backlights tend to need very careful tuning to work properly alongside high refresh rates and particularly with things like VRR. Will VESA account for this? Will a screen with a FALD where response times might be impacted a bit to allow HDR to look right and optimal be penalised in its motion clarity rating compared to a lowly HDR 400 screen without any backlight dimming at all? Even if the HDR clearly looks miles better on the first? Maybe the motion clarity is impacted a little, and for this specific measure it should be moved down a tier, but what if that was done in order to offer a proper HDR experience, whereas the HDR 400 display is offering no real HDR performance at all, but achieving a better ClearMR rating because of that? It gets complicated and there’s a lot of additional considerations for measuring HDR displays that will need to be thought through.
We have mixed feelings about this new approach from VESA to be honest. On the one hand we agree that G2G specs and MPRT specs are of little value any more and need to be retired. In their place we need a decent way to measure and categorise display motion clarity so that consumers can easily compare between models and understand what they are buying. ClearMR gets part way towards that and we welcome the attempt by VESA to try and standardise something, but unfortunately has a lot of holes, and that brings in to question it’s validity overall.
We’ve talked about the testing criteria and process, and we’d like to see that improved by VESA if possible to make it more robust. The current approach is too limited in scope, too open to manufacturer abuse, and will leave a lot of gaps in customer expectations of a displays motion performance. The performance tiers do not seem appropriately spaced either given the current ranking of the screens certified so far, something doesn’t look right even in these early days. “The ClearMR logo was developed to give consumers a straightforward metric for comparing performance across products” VESA say. We’re not convinced this has achieved that just yet.
Only displays that pass all ClearMR compliance tests can qualify for the VESA Certified ClearMR logo which of course means display manufacturers have to pay to get their display certified at an approved test centre, which means there’s a charge for this scheme and money coming in to VESA for the certification. We can’t help feel like this is also partly a cash grab by VESA, introducing yet another badge and logo that manufacturers have to pay for. This does also mean that unless every manufacturer gets on board and sees value in this scheme, and wants to pay for it, then you could have some displays without any logo at all, and we’re right back to where we were before being unable to easily compare between different options. A display having the logo doesn’t mean it’s any better than a display without the logo, it just means the manufacturer didn’t bother paying a test centre to certify it for them. How many manufacturers adopt this scheme and see value in it remains to be seen. We expect it’s the kind of thing where if enough manufacturers take part, the others will follow so as not to get left behind.
To conclude, the tagline on the VESA ClearMR website says “Life isn’t blurry. Why should the motion on your display be?” – I’d answer that with “why should your certification scheme be?”
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