Why Fake Refresh Rate either blows your mind, or your nerves.
A few days ago we asked our Twitter audience if they usually turn off True Motion. It turns out that most of our friends are not aware of what that is. But we're here to help :)
For starters, TruMotion, or whatever you call it, should not be confused it with the app of the same name, is a technology that assumes many names and it happens that TruMotion is just was LG calls it.
- Samsung calls it Motion Rate
- Sony goes with MotionFlow
- LG can’t decide between TruMotion (Oh, the cheeky typo) or Motion Clarity
- Vizio simply called it Effective Refresh Rate
- For Panasonic is Backlight Scan
Despite it the creative aliases, which should make any marketing department proud, the principle is always the same: to fake the refresh rate of a TV.
What about the Real Refresh Rate.
Let's start by tackling the difference between Refresh Rate and Frame Rate.
Refresh Rate is the number of times per second your monitor (TV, monitor, projector...) can redraw the screen and is measured in frequency (Hz). On the other hand, Frame Rate concerns the source video and the number of frames that were captured while filming it (or producing it if we're talking about video games and animated movies).
In other words, if a monitor that's able to reproduce video at 60hz (can redraw the screen 60 times per second), when watching a movie there are still only 24 separate frames displayed every second, but they may need to be shown multiple times, depending on the refresh rate.
So, if a television works at 60hz, it will be refreshing the image 60 times per second. That's the real refresh rate.
Simulated (Fake) Refresh Rate
Have you ever walked into a store where a display TV is showing off its capabilities, and all you can see is a Hollywood blockbuster where everyone and everything moves like if it was a Mexican telenovela?
That’s because movies are filmed at 24 frames per second. Except for that one…
Most of the television’s content such as sports, new reports, tv shows, are 60 frames per second (or hertz).
If most of what we watch demands no more than 60hz, why do we need have fake refresh at higher rates?
A natural explanation that's not entirely incorrect would be to say that, marketing wise, it works. But let's explore the technical aspects of it.
Imagine a very fast paced movie scene such as a chase. Things can get blurry in those instances. It’s only normal. It happens because the display can’t refresh quickly enough. The problem is that the source material cannot doesn’t higher than 24 to 30 frames per second if we're talking about movies and series, or up to 60 frames per second in some sports broadcast.
TV manufacturers employ different forms of visual trickery to “enhance” the image. They fool your brain into thinking that you’re watching something at native 120hz using the following techniques:
- Backlight strobing - works by only turning on the display’s backlight for a fraction of the display cycle and instead just show a black screen for the rest of the cycle. This creates the illusion of more frames.
- Sample and hold - will display a static image for a full 1/60th (or whatever the refresh rate is) for a second before showing the next one.
- Black frame insertion - Works just like backlight strobing, but instead of turning the backlight on/off, it just displays a black frame.
- Motion Interpolation - it involves a processor within the TV’s board generating intermediate frames that are inserted between actual frames from the video source. Imagine a car going from point A to point B. This technology would kind of recreate the car where your eye would expect it to be, thus making everything look “smoother.”
Basically, they're adding fake frames that weren't originally there.
Enter the soap opera effect.
This video shows image interpolation in its glory. But is it glorious?
While image interpolation may help the picture quality when watching fast-paced sports. Its effect on movies, even action scenes, is a whole different story. Consensus is the last thing you'll find on youtube comments for movie clips rendered to higher frame rates.
One good example would be this Mad Max trailer. Remember, it was shot at 24 fps, but this YouTube shows it as 60 fps using a fake refresh rate rendering to create the "missing frames." Comments are polarizing, to say the least.
Fortunately, most TV manufacturers allow you to access settings to adjust the amount of the added refresh or even turn it off.