Blur Busters Forums

RealNC wrote: ↑

05 Jun 2026, 14:07

Yes. It's a predictive algorithm that needs to take into account the frame times of previous frames and then predict what's gonna happen. If it was easy, every monitor would have it But it's not, and usually display vendors don't care much. And it's also the cost. It might require a faster scaler to run this algorithm instead of a cheap one.

Unless it's some kind of productivity monitor, or cheapest you can find for "it has a picture", these days it has VRR, usually the Freesync kind for the cheaper ones.

And even 1080p120 ones are pretty cheap.

Tho those maybe don't have variable OD, but then again how do you VRR at all, I've kinda skipped the early non-OD VRR screens.

Still don't know how you can predict rapid/unstable FPS change.
Unless you buffer 1 frame all the time, but the point of VRR is to have no tearing and low lag?

RealNC wrote: ↑

05 Jun 2026, 14:07

If you see two images there, then it's not a double-image effect. It's crosstalk.

RealNC wrote: ↑

05 Jun 2026, 14:07

It results in blur, not double-image. With sample-and-hold, the object stays visible at a fixed position while your eyes are moving. This creates a blur trail. The more times the same frame is repeated, the bigger the blur trail gets.

Sample-and-hold: blur
Strobing: double-image

They both have the same cause behind them: your eyes are moving while the screen only shows static frames.

Yeah I just tried this with PS1 emulation, since it's usually 30FPS (in 60FPS window, but irrelevant), Medievil game, since his running animation has a lot of jerky movement, with ShaderBeam.

Since it's 30FPS, on 240Hz, I can try 2, 4 and 8 subframes, Global refresh mode.

Indeed, if my eyes track anything, the less the subframes, the more the double images appear, and his movements become slightly harder to read even tho his position is static on the screen but he is never truly double-image'd.

8 subframes is flickerfest, but it's sharp and clear, aka no blur nor double frames.
4 subframes seems sharp but has double images, can't say I notice blur.
2 subframes I can tell it's blurry along with double images.

Haven't seen crosstalk tho, at least I think I didn't, so I fired up Mario quickly to check, when running and in the middle of the screen, no double images on his sprite.

Thanks for sending me down this hole

This popped a question in my mind - I know cinemas use(d) strobing and 24FPS.
Regardless if it's mechanical shutter, or digital BFI, how come people didn't complain about watching 24@48hz or 24@72hz?

2mg wrote: ↑

07 Jun 2026, 21:27

Still don't know how you can predict rapid/unstable FPS change.

Rapid spikes can't be predicted, but it doesn't matter because severe stutter is not gonna be helped any by having a good OD prediction. Whenever a game stutters/hitches (shader compilation, traversal stutter, whatever,) you're not seeing any ghosting to begin with because all you see is the stuttering, which is not perceived as motion anyway, but rather as a slideshow of images. For motion to be ghosting, you need to have something that you perceive as motion to start with

What can be predicted is where the frame rate is most likely going to be next by taking into account your average FPS of the last 100 frames or whatever the algorithm uses, and whether the graph is trending upwards/downwards or is flat. It's math and huge lookup tables for the colors and their corresponding voltages. Complicating it further is the need to use different voltages depending of what the previous color of a pixel was. If it's a simple g2g transition, things would be a bit easier, but we use color displays now, and thus a variable overdrive implementation gets really complex. I couldn't create one for sure, even though I do know math and am a dev. This requires some serious engineering.

This popped a question in my mind - I know cinemas use(d) strobing and 24FPS.
Regardless if it's mechanical shutter, or digital BFI, how come people didn't complain about watching 24@48hz or 24@72hz?

AFAIK, the standard strobe rate in cinema was 72Hz, so every frame was tripled. The triple-image effect didn't matter much because movies are shot using long camera exposure times to get as much "real" motion blur as possible, which masks the triple-image effect.

RealNC wrote: ↑

07 Jun 2026, 21:55

AFAIK, the standard strobe rate in cinema was 72Hz, so every frame was tripled. The triple-image effect didn't matter much because movies are shot using long camera exposure times to get as much "real" motion blur as possible, which masks the triple-image effect.

Could be.
Technically I can try a PS1 game with some camera exposure/blur shader and ShaderBeam.
Tho physical cinema shutters let light thru in a more of pseudo sample-and-hold way, the light starts going thru it top to bottom until the entire frame is visible which is immediately followed with a blanking part that covers the light top to bottom.

Anyway thanks for answering, I appreciate it!

2mg wrote: ↑

Yesterday, 13:37

Tho physical cinema shutters let light thru in a more of pseudo sample-and-hold way, the light starts going thru it top to bottom until the entire frame is visible which is immediately followed with a blanking part that covers the light top to bottom.

In slow motion:

https://www.youtube.com/watch?v=3v9Y8iEN8Ck

And a slow motion of a super 8 projector's light shutter:

https://www.youtube.com/watch?v=DfBqIpkeRqA