Nothing Refreshing About Refresh Rates This Year
Back in 2012, the HD Guru warned readers that most TV manufacturers had started substituting industry standardized specifications for LED LCD TV motion smoothing technologies with proprietary terminology and corresponding numbers that at first glance appeared to be high native refresh rates but actually weren’t.
Here we are in 2015 and the practice, for the most part, continues although most companies at least have made efforts to explain why their marketing practices aren’t intended to deceive, but to more accurately explain how their systems produce benefits in reducing motion blur beyond what’s possible with native refresh rates alone.
In most cases, however, the reason for the practice is that as prices decline for TVs year after year, and profit margins shrink, manufacturers looking to maintain competitive price points have had to step down the quality of expensive high refresh rate panels they’ve traditionally used.
More on refreshed refresh rates after the jump:
In 2012, HD Guru called foul on the practice because panels with native refresh rates offer a better way to smooth out motion artifacts in LCD TVs. It also made it easy for consumers to quickly determine the quality of a TV panel by comparing the Hertz numbers of one TV against another. TVs that use more expensive panels produce up to 120 individual picture frames per second (120Hz), where motion smoothing technologies that are being substituted instead of high refresh rate panels use tricks like inserting black fields between frames to create back light flicker to trick the eye into seeing a smoother image.
Unfortunately, things don’t appear to have gotten much better, and today the best way to determine how a television handles motion resolution is with an in-person demonstration, or by following a trusted product review. Spec sheets alone won’t cut it any longer.
The motion blur artifact, which has been a problem for LCD TVs since they first appeared in the market, is seen in pictures where images of fast moving objects are distorted, smeared or show a trail of pixelated dots following the subject.
Unfortunately, panels that used the highest native refresh rates – the best method of controlling the blurring issue – have stepped down in frequency rates to a maximum of 120Hz this year. The manufacturers’ invented motion smoothing terms and numbers continue to appear on web sites and in product documentation, with fewer and fewer even bothering to list “native refresh rates” any longer. In some cases a manufacturer will give you the number if you specifically ask for it, but some won’t reveal the number at all.
After threatened or pending litigation, most manufacturers today have begun ensuring that their retail partners and agents refrain from placing “Hz” of “Hertz” next to these numbers on shelf signage and internet postings. However, one manufacturer continues to list “effective refresh rate” in online specifications, with no qualifying native refresh number.
A number of major retailers, including Best Buy, Crutchfield and Amazon, list the actual native refresh rate of a TV panel, when available, as does HD Guru whenever possible in new product announcements and in product reviews. When shopping for a new TV, it’s important to make sure you are not comparing the native refresh rate on one set against the proprietary motion smoothing technology name and number a manufacturer has posted for another set, or you might get less than you bargained for.
Meanwhile, in March 2015, a class-action lawsuit was filed against LG Electronics USA for allegedly advertising deceptively high refresh rates. The lawsuit alleges that LG used invented and misleading technical terms and ratings systems, including “TruMotion” and “Motion Clarity Index,” in marketing information.
We gave LG a generous amount of time to comment on the allegations raised by the legal challenge, but received nothing as this was posted. A law firm has also advertised online for testimony concerning cases of misleading refresh rate information from Vizio. The law firm did not reply to our requests for comment on the effort.
What is Refresh Rate?
As we pointed out in 2012, all LCDs (including LED LCD TVs) originally suffered from blurring of fast moving objects or fast panning in content. This artifact is referred to as “motion blur.” To reduce motion blur, manufacturers developed televisions that refresh (show) a new image faster than the standard rate of 60 times per second (stated as Hz or Hertz). Using a technique called frame insertion, the TV creates new additional images that are inserted between the real, original image frames. This year, television makers offer HDTVs and 4K UHDTVs with native refresh rates of 60 or 120Hz. This is down in 2015 from a high of 240Hz last year. The higher the rate, the less motion blur, and the more expensive the panel.
TV makers advertise these higher rates as a step-up feature, with 120 Hz TVs providing better motion performance than a 60 Hz version. These numbers have been around long enough that prospective buyers see a number such as 120, 240 of higher on the box and assume it is the TV’s native refresh rate. As such, they expect to pay more for a higher refresh rate model.
As we stated earlier, TV makers also use another technique to reduce perceived motion blur, called a scanning backlight or “black frame insertion.” This is often accompanied by some additional, unspecified signal processing. These methods don’t change the refresh rate at all, instead they scan or turn off the backlight in a way that mimics some of the performance benefits of a faster refresh.
To communicate some of these systems to reduce blurring, manufacturers are using terms including “120 Clear Motion Rate” or “120Hz effective refresh rate.” But, there is a significant hardware difference between a true 120Hz refresh rate TV and a 120Hz “effective refresh rate.”
A 120Hz “effective refresh rate,” usually means a model has a 60 Hz native refresh rate and adds “black frame insertion” that flashes the backlight in a way to justify calling the TV “120.”
TV makers say their various motion processing system numbers give consumers a better idea of how the TVs handle motion. They are implying that a “120 Motion Rate” television is equivalent to a competing HDTV that actually displays a new frame 120 times per second by using a higher cost LCD panel and faster processors. We disagreed with that assessment in 2012, and that position has not changed today.
The following addresses how various top-tier TV manufacturers are communicating their motion smoothing technologies and how these approaches have changed for 2015:
In 2015, Samsung dispensed with the use the term “Clear Motion Rate” (CMR), and now uses the terms: Motion Rate 240 (used for most 4K UHD TVs); Motion Rate 120 (used most for Full HD TVs) and Motion Rate 60 (used for entry series models, and smaller screen size series).
When using CMR in the past, Samsung used additional numbers including: 480, 840, and 960.
Steve Panosian, a Samsung TV technology spokesman, explained for us that “CMR was aimed at improving motion resolution with video processing and LED controls. We ended up with too many CMR ratings, it was complicated to explain performance benefit from one series to the next putting aside screen sizes (the bigger the screen, the more perceivable the motion blur regardless of the spec).”
In 2012, Samsung issued a white paper explaining their CMR number, and issued HD Guru a test pattern, but the method used proprietary test signals, and specialized equipment that still has not been made available to HD Guru for product evaluations.
Panosian said Samsung believes, “the panel’s refresh rate in a world of LED back-lit LCDs doesn’t tell the story and complicating the issue is a lack of motion measurement standards. CCFL backlighting [used before LEDs in LCD TVs and monitors] is always on. Motion blur is perceived because of the LCD panel’s inability to control an equally fast or instant `off’ state. Hence, light continues to pass through the screen and the moving image blurs.
“LED backlighting can be driven to turn off, dim with software, and improve the perceived motion blur with light control,” Panosian continued. “Add frame interpolation, dimming zones and other techniques, and manufacturers arrive at marketing terminologies.”
Panosian said Samsung has attempted over the years to raise the refresh rate standard issue with the Consumer Electronics Association (CEA), without success and on more than one occasion.
A spokesman for the CEA did not reply to our request for comment as this went to post.
Panosian said Samsung does not use the term “effective refresh rate” in association with its Motion Rate terminology. It also doesn’t provide native refresh rate numbers any longer.
In addition, he said Samsung has instructed retail partners not to use Hz or Hertz in association with its Motion Rate numbers. However, HD Guru found Amazon listing “240 CMR (Effective)” on its page for the new UN65JS9500 SUHD TV and other models.
As we pointed out in 2012, Sony uses the term Motionflow XR followed by a 240, 480, 960 and this year 1440 number, depending on the model.
When MotionFlow was first introduced, Sony explained that it uses frame insertion (interpolation), LED backlight blinking (line blinking), and image blur reduction via signal processing. So, for example, a Motionflow XR 960 can be found by multiplying the native refresh times four (240 x 4=960) or as Sony told us: “With frame interpolation, four distinct images in the same time period of 1/60th of a second. 240 Hz times 4 = 960.″
Sony said there have been a few improvements made to MotionFlow this year.
“MotionFlow has always been a combination of a fast panel, backlight control and frame interpolation. Depending on the customer use, there are different modes customers can choose from to optimize their viewing experience.” Sony told us.
This year Sony said it added a custom mode “where the customer can adjust both the amount of frame interpolation and backlight control to make the perfect motion compensation mode for them.”
A Sony spokesperson told us the company’s practice of using XR numbers for identifying motion smoothing technology isn’t deceptive because, “motion smoothness is based on the viewer’s perception. For example, blinking the back light one time gives you the same perceived smoothness as doubling the panel refresh rate. In addition, visible motion blur is a combination of how your brain processes the video signal as well as the panel refresh rate. Both factors need to be addressed for the customer to perceive smooth and lifelike motion.”
For those who would rather shop for a TV using native refresh rates, Sony told HD Guru that it continues to provide native refresh rate numbers when asked for them, because, “We want customers to know both the native refresh rate as well as MotionFlow rates.”
However, the specs page for TV models like the 65-inch FullHD KDL-65W850C on the Sony online store site shows only a MotionFlow XR 960 number. Sony does supply retail partners such as Crutchfield with both the MotionFlow and native 120Hz refresh rate numbers.
Asked why LED LCD panels available in 2015 top out at a 120Hz native refresh rate, where in the past, some models had refresh rates of 240Hz and higher, the Sony spokesperson said, “4K panels have to write four times the data as an HDTV panel so developing a panel and processing to allow a 240Hz native refresh rate becomes cost prohibitive. If you can get the same motion smoothness with backlight control (backlight blinking), the customer gets the same benefit at a lower cost.”
Sony said its MotionFlow technology works the same on 4K Ultra HDTVs and Full HDTVs, even though the corresponding MotionFlow numbers may be different.
“The increase in number is a result of more efficient backlight control which is why a full array set like the X940C has MotionFlow 1440,” a spokesman told us.
According to Sony, the best way to buy a TV is to get a demonstration and see the results of the refresh rate technology for yourself.
“A 120Hz panel leads to a better rendition when playing native 24p content, so for avid movie enthusiasts they would likely prefer a 120Hz 4KTV. For MotionFlow, even if you compare the numbers for two different manufacturers, the results would be different because processing varies due to how each manufacturer does the frame interpolation. Customers should go and demo different TVs for themselves to see the difference and choose the TV that looks best. That is the best way to ensure customers get the best performance,” the Sony spokesperson said.
Sharp continues to use the term AquoMotion, such as AquoMotion 240, in marketing the capabilities of its 2015 Aquos LED LCD TVs. It is double the actual refresh rate. An AquoMotion 240 LED is really a 120 Hz refresh HDTV.
Sharp told HD Guru that AquoMotion uses a combination of frame refresh rate, image processor speed and backlight scanning technology to create clear images during fast-motion scenes. Sharp’s Aquos televisions provide the option to adjust motion rate or even turn it off completely, to optimize the content they are watching.
Sharp said it includes both native refresh rates and the AquoMotion rate online at SharpUSA.com and on spec sheets. The company’s 2015 4K Ultra HDTVs use either 60Hz or 120Hz native refresh rates, determined by the model series.
Three years ago, LG called out its TruMotion technology, typically followed by 120 Hz and 240 Hz, telling HD Guru they were native refresh rates. Subsequent tests by HD Guru found the 120 Hz TruMotion set was actually producing a 60 Hz real refresh rate.
Contacted this year, LG told us that it “uses a combination of state-of-the-art features and techniques to optimize the display on LCD/LED TVs by reducing motion blur, improving contrast, increasing sharpness, and otherwise enhancing picture quality.”
“Depending on the year and model, the features and techniques employed may include the use of LG’s proprietary engine featuring built-in software that automatically adjusts graphic settings such as brightness, sharpness, and color, as well as motion interpolation, backlight scanning, advanced local dimming and other picture improvement techniques,” a spokesperson told HD Guru. “By increasing the frequency with which the display updates the information on the screen (otherwise known as the `refresh rate’), motion interpolation and backlight scanning each reduce motion blur. All LG LCD/LED TVs with either our TruMotion or Motion Clarity Index (MCI) rating use one or both of these techniques to help reduce motion blur.”
Like other TV manufacturers mentioned here, LG contends that “refresh rate is far from the only way to measure and discuss the improvements in picture quality LG achieves. In 2014, LG developed the MCI rating to provide additional information regarding picture quality and represent the benefits of the various technologies employed on LG TVs. Simply put, the higher the MCI, the better the picture quality.”
In the past, consumers troubled by motion blur had the option of buying a plasma TV from LG, Samsung, or Panasonic. Plasma technology didn’t suffer from motion blurring, and provided many additional picture quality benefits. But declining demand forced all manufacturers to end plasma production at the end of 2014.
Unfortunately, new Organic Light Emitting Diode (OLED) TV technology, which like plasma offers many benefits over LCD TVs, also exhibits some degree of motion blur in fast-moving images. We asked LG for an explanation, but received nothing as this was written.
Panasonic used to list native rate on its 240 Hz panels and also lists “backlight scanning 1920″ as 240 refresh times 8 sections. This year’s 4K Ultra HD products list panel drive as “Image Motion 240Hz” for the flagship X850 series 4K UHD TVs in the company’s online store. The company is not listing separate native refresh rates on the spec page, but Panasonic told us the X850 products had a native 120Hz refresh rate, which is half the posted number for the “Image Motion” rate.
Vizio used to use the term Scenes Per Second (SPS) to denote its TV’s refresh rate. This year the SPS reference and number have been changed, showing “effective refresh rate” in model specs. A Vizio representative told us that generally the native refresh rate for the TVs is half what is listed in the “effective refresh rate” number, but the company did not respond to our questions as this was posted.
According to Vizio press materials, the company uses a technology called “Clear Action,” which combines “powerful image processing and high-speed effective refresh rate with precise backlighting that synchronizes with the content on the screen to reduce motion blur and minimize retina burn.”
Vizio’s press materials explain that with Clear Action “when a pixel is lit for too long, you see motion blur. By reducing the time a pixel is lit, Vizio greatly enhances fast action performance.”
Clear Action shortens backlight ﬂashes per refresh, resulting in lower persistence, which leads to reduced motion blur when your eyes are tracking moving objects, the company said.
Image blur is an issue that bothers people to different degrees. Anyone who watches a lot of sports and has a big screen set is going to notice it to a greater degree than someone with a smaller-screen set used to watch the news, movies and sitcoms. In time, the eye learns to ignore the artifact for some people. Still, it is an issue that is important to many customers and we would like all TV manufacturers to at least go back to the practice of posting native refresh rates alongside their marketing terms to give shoppers a better understanding of what it is they are buying. Better yet, we agree with Samsung that it is time for some form of industry standardization of motion rate terminology so shoppers can compare performance numbers when buying TVs online.
By Greg Tarr
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