External BFI Injection -- I am working with Retrotink 4K!

[BFI]

Chief, if the RT4K ran 100:75:50:25 dimming for 60fps at 240Hz, would the MPRT be 10.4, and would this sequence be adequate to hide DLP dithering?

I have a 120Hz projector so I'd expect to see weird colors with 1:0 BFI.

And if I understand correctly, 60fps lag would remain at 16.7ms on a PJ with 8.3 at 120Hz and 4.2 at 240? Plus the processing lag of BFI, if you have any idea what that is?

[Chief Blur Buster]

Chief, if the RT4K ran 100:75:50:25 dimming for 60fps at 240Hz, would the MPRT be 10.4, and would this sequence be adequate to hide DLP dithering?

DLP dithering is subrefresh based and is unhideable. DLP color depth gets worse when you add BFI to DLP, due to decimation of temporal dithering. However, for primary-color retro stuff, it is typically acceptable. And does reduce DLP motion blur. But does not fix DLP temporal dithering which occurs at 1920Hz-2880Hz independently of refresh cycle / frame frequency.

[BFI]

Would the Hisense U7K be a good candidate running 1080p at 240Hz?

https://www.rtings.com/tv/reviews/hisense/u7k-u7-u75k

I can't read the street names on your test at 60Hz on my projector, but I can with some blurriness at 120. With sequential 3D enabled I can read them perfectly. Unfortunately 3D increases lag to 27.2ms (Optoma HD29HST with Leo Bodnar 4K).

The thing I hate most about 60Hz strobing is flicker, which I don't notice at 120, so I'd love to try something like F:H:H:B with the RT4K for 60fps at 240, where F is full brightness, H is half and B is black. Might you be working on anything similar?

[Chief Blur Buster]

Would the Hisense U7K be a good candidate running 1080p at 240Hz?

https://www.rtings.com/tv/reviews/hisense/u7k-u7-u75k

I can't read the street names on your test at 60Hz on my projector, but I can with some blurriness at 120. With sequential 3D enabled I can read them perfectly. Unfortunately 3D increases lag to 27.2ms (Optoma HD29HST with Leo Bodnar 4K).

The thing I hate most about 60Hz strobing is flicker, which I don't notice at 120, so I'd love to try something like F:H:H:B with the RT4K for 60fps at 240, where F is full brightness, H is half and B is black. Might you be working on anything similar?

That'd be an interesting candidate! But, with lots of caveats; it may not outperform LCD 120Hz in BFI ergonomics, even if you can get lower persistence than 240Hz. When we're at 240Hz stratospheres, I start to recommend OLED for better BFI performance (Better motion clarity + better brightness of panel-level non-backlight-based BFI, when HDR nits-boosted).

Retrotink 4K does not yet support advanced BFI algorithms, but I am in talks about the possibility. Please join the Retrotink Discord and tell Mike you want him to work with me for firmware upgrades to more advanced BFI algorithms.

Also, CRT electron beam simulators is something I am working on. Rolling strobe is something that is gentler than 60Hz global strobe, and remember that 60Hz BFI at the panel layer (LCD/OLED) is already a defacto rolling strobe. At 120Hz, the 60Hz BFI rolls in-and-out in 1/120sec, and at 240Hz BFI rolls in-and-out in 1/240sec. It's not subrefresh rolling BFI, just an artifact of a panel not refreshing all pixels at the same time, High Speed Videos of LCD Scanout. If you get eyestrain from 60Hz LCD strobe but no eyestrain from 60Hz CRT or rolling strobe, then you might want to retest Retrotink on a modern 120Hz LCD/OLED and see if non-backlight-based BFI is gentler on eyes.

And I have to admit it's neat that 240Hz is finally arriving to television sets. And a budget brand, a HiSense, that!

240Hz will probably be the next mainstream refresh rate in the 2030s. High Hz is no longer just for esports.

That being said, 120Hz 50%:50% panel-level BFI may be more ergonomic than you thought due to the rolling nature of individual refresh cycles; Have you ever tried non-backlight-based BFI? Either on OLED or on LCD? OLED does a better job though.

[BFI]

Great answer, thanks!

I bought a Sony A80J two years ago but returned it because I found it stuttery in comparison to the BenQ DLP I had. I also found its 60Hz strobing uncomfortable (85Hz was my comfort baseline on CRT). I'm not very demanding of color accuracy and happy with SDR, and because I think 1080p looks great on CRT I'm not chasing resolution either. So the quality downsides of that Hisense wouldn't bother me if it responded well to injected BFI at 1080/240. I note it has a slower pixel response than OLED.

I'm hugely interested in your beam simulator, especially if 480Hz monitors mean increased granularity to better mimic phosphor reactions.

"At 120Hz, the 60Hz BFI rolls in-and-out in 1/120sec"

I'm used to global strobing adding a black frame to the middle of each frame of 60 at 120Hz, resulting in double images. 120Hz rolling scan displays the top half of each 60 first and then the bottom half, avoiding double images with markedly reduced flicker over global 60Hz strobing? As I understand it. Can the RT4K support this and would it suit DLP any better than global?

(I'm 90% happy with DLP at 8.3ms persistence, if only all console games were 120fps!)

75% brightness loss at 240Hz though (unless using 50:50 to take advantage of the higher Hz, presumably reintroducing double images). Input lag would be the display's 120Hz figure x2 or 240Hz x4, so possibly a slight increase over its 60Hz lag.

I'll join Mike's discord.

[Chief Blur Buster]

I'm used to global strobing adding a black frame to the middle of each frame of 60 at 120Hz, resulting in double images. 120Hz rolling scan displays the top half of each 60 first and then the bottom half, avoiding double images with markedly reduced flicker over global 60Hz strobing? As I understand it. Can the RT4K support this and would it suit DLP any better than global?

We're not talking about sub-refresh rolling scan (intentional rolling BFI) or software-based additional rolling scans (e.g. subdividing consecutive refresh cycles in gradiented/segmented rolling BFI)

We're just piggybacking on natural hardware-based rolling scan (indepedent of BFI <-- make sure you understand this educational pre-requisite first before trying to understand beyond. Stop reading this post if you don't understand yet).

Where 60Hz = 1/60sec roll, and 120Hz = 1/120sec roll, and 240Hz = 1/240sec roll.
(for MOST modern panels, LCD or OLED).

Remember, a lot of panels will roll at their MaxHz speed, even at their lower refresh rates, which means getting a 240Hz LCD only to run software-based 60Hz-in-120Hz BFI to try to do a slower roll -- may not work. 240Hz is GOOD for lowering motion blur (75% blur reduction) of 60Hz by using 75%:25% BFI. However, if your GOAL is reducing flicker, 120Hz native panel + software BFI is the most ergonomic "60Hz" global BFI solution, just merely only piggybacking on natural BFI-independent rolling refresh cycles.

Adding 120Hz BFI simply only means the visible frame rolls in 1/120sec, and black frame rolls in 1/120sec, even for 60fps material. Doing 240Hz means you've got faster rolls, 1/240sec rollin/rollouts, which might be too fast/less ergonomic relative to 60Hz. You want the roll to be as slow as possible, so that's why 120Hz (the minimum Hz needed for software BFI for 60Hz) will have the preferred slower 1/120sec rolls rather than 1/240sec rolls.

It's possible to also do software-based rolling scans but you need extremely high number of refresh cycles to do so, to prevent tearing artifacts and banding artifacts. For example 8:1 or 16:1, so I need a 480Hz OLED to do software-based slow-rolling-scan (1/60sec to roll from top to bottom in a simulated software based manner). Even those "slow" software based rolling scans are still hardware "fast" rolling scan updated (e.g. 1/480sec sweeps), so for future CRT electron beam simulators, I have to brute-force it out, to avoid artifacts from the interplay between the slow software-based rolling scan BFI algorithms of the future, and the native hardware-based rolling scan of the panel (irrespective of BFI or no BFI).

[blurblurb]

maybe this was answered earlier in the thread but if i were going to buy this to use with retro consoles it would need this feature:

accept analogue interlaced signal from at least composite (but also RF would be even better) and while keeping the colors NTSC accurate display the console's output on a modern OLED in a way that preserves the special effects most pre-Y2k consoles (and even computers) used that relied on NTSC signals/displays

the most well known example of this kind of effect are the sega waterfalls but without getting into a technical discussion about that one particular example, there are tons of other times NTSC stuff allowed many different kinds of effects for many different games and platforms

obviously the second most important thing is how well this device will work with my laserdisc players?