Black frame insertion demo. Half the light, twice the clarity.
Strobing modes on monitors and black frame insertion on TVs shorten how long each frame stays lit, which is what makes motion blur. This shows the effect in software: one row every frame, one row with black between frames. It flickers, which is the cost, and you can skip it.
One check
- Black frame insertion
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
What it measures
Measured here, not assumed.
- Persistence
- How long each frame is lit. The lower row halves it, so a moving mark blurs half as much.
- The cost
- Half the light, and flicker at half your refresh rate. At 60 Hz that is 30 Hz flicker, which most people see; at 240 Hz it is 120, which most do not.
- Why it is a menu option
- Monitor makers call it ULMB, ELMB, DyAc, MBR or 1 ms MPRT. They shorten the backlight flash instead of drawing black, which is the same idea with less flicker.
If it fails
The usual failures, and what fixes each.
- It flickers badly
- That is expected at 60 Hz. The effect is meant for high refresh panels, where the flicker is above what the eye sees.
- The lower row is too dim
- Also expected: half the frames are black. Monitors compensate with a brighter backlight in strobe mode.
- You want it in games
- Turn on the monitor's strobe mode in its menu; it is off by default. It usually disables variable refresh rate.
Where a browser stops
What it cannot tell you.
- This is a software imitation: the browser draws black frames. A monitor's strobing backlight does it better, without the halved frame rate.
- The flicker is real and can affect people with photosensitivity; the demonstration waits for a press and can be skipped.
- A page cannot measure your panel's strobe mode; this shows the principle.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Black frame insertion demo, answered
- What is black frame insertion?
- Showing a black frame between every two real frames, so each real frame is lit for less time. The eye sees less blur on moving objects, and less light overall.
- Does black frame insertion reduce motion blur?
- Yes, in proportion to how much it shortens the lit time. Halving it halves the blur, the same as doubling the refresh rate would, at the cost of brightness and flicker.
- Why does it flicker?
- Because the screen is dark half the time. At high refresh rates the flicker is too fast to see; at 60 Hz it is not, which is why the demonstration warns and waits.
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