New levels of Adaptive-Sync performance eliminate misleading response times, flickering

So you’re looking at a monitor or laptop that says it has Adaptive-Sync or Variable Refresh Rate. Maybe it’s Nvidia G-Sync or AMD FreeSync. Perhaps the vendor was detailed enough to include an Adaptive-Sync range indicating the refresh rate range, as well as a response time metric and an overdrive feature promising super-smooth video playback. But then you see a bunch of other monitors and laptops claiming the same thing. How to determine which display is best for multimedia content?

To help, the Video Electronics Standards Association (VESA) on Monday launched a program to certify PC monitors and laptop displays with Adaptive-Sync. The Adaptive-Sync Display (Adaptive-Sync Display CTS) Compliance Test Specification aims to provide more information about anti-tear screen technology.

The program, which has already certified some products, has more than 50 criteria for two levels: MediaSync Display, which is video-oriented and requires an Adaptive-Sync range of 48 to 60 Hz, and Adaptive-Sync Display. which is focused on gaming and requires Adaptive-Sync fury of at least 60 to 144 Hz.

A Deeper Look at Adaptive-Sync Performance

In 2014, VESA — a non-profit group of hardware, software, computer, and component manufacturers that also develops standards for mounting DisplayPort, DisplayHDR, and VESA monitors — added Adaptive-Sync protocols to the DisplayPort video interface. Adaptive-Sync, which includes displays like Nvidia G-Sync and AMD FreeSync, should make video playback smoother by eliminating screen tearing, judder, and flicker. Adaptive-Sync also aims to provide lower power consumption and efficiency when working with content played at different frame rates.

Adaptive-Sync is now available in all types of monitors, including gaming and regular. It is also supported by major GPU vendors. The Nvidia and AMD variants provide further optimizations for their graphics cards and may have different image quality requirements, depending on the type of G-Sync or FreeSync.

In order to provide a more detailed preview of the expected performance of an Adaptive-Sync monitor or laptop at default settings, VESA – after two years of development with more than two dozen contributors including Nvidia, AMD, Intel and display manufacturers, display drivers, processors and other components launches the Adaptive-Sync certification program with more stringent requirements. You can use an Adaptive-Sync, G-Sync, and/or FreeSync display without the new MediaSync Display or Adaptive-Sync Display standards. But getting one of the new logos means the monitor has passed extensive VESA testing, which we’ll get to soon.

But before that, it should be noted that monitors require DisplayPort to receive one of the certifications. This makes it impossible for HDMI-only Adaptive-Sync monitors to get the new logo. This move becomes more interesting when you consider that HDMI 2.1 introduced variable refresh rates as a standard.

Increased requirements for both levels

The most basic requirements of the new levels are established Adaptive-Sync ranges. The MediaSync Display layer requires an Adaptive-Sync range of 48Hz to 60Hz. For the gaming oriented level of Adaptive-Sync Display, the range is a wider range from 60 to 144 Hz.

But that’s just the beginning of what a monitor has to go through to get one of the VESA logos.

Jitter test

According to VESA, in order to receive MediaSync or Adaptive-Sync certification, a display must exhibit less than 1ms of jitter, well below what the human eye should be able to see.

This figure must meet 10 international frame rate standards: 23.976 Hz (Hollywood movie); 24, 30 and 60 Hz (usually content shot on consumer cameras, like YouTube videos or something played locally), 25 Hz (UK TV), 29.97 Hz (US TV), 47.952 Hz (rare, but used in some films), 48 Hz (also used in rare films), 50 Hz (British sports) and 59.94 Hz (American sports).

VESA then tests the display in the monitor’s minimum Adaptive-Sync range. For example, if a monitor has an Adaptive-Sync range of 40 to 60 Hz, VESA will test it at 40 Hz, even if the MediaSync display level only requires a range up to 48 Hz and Adaptive-Sync level 60 Hz. If a monitor’s Adaptive-Sync range has a higher minimum than the certification requires, VESA will double the frames that are slower than the minimum.

One common cause of judder is 3:2 conversion, which is used to display Hollywood movies shot at 23.976 Hz and results in one frame per second being dropped. The VESA certification aims to eliminate the need for a 3:2 conversion.