Custom OLED Rolling Scans -- Custom Built OLED Monitor

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matteo
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by matteo » 11 May 2017, 16:20

Thank you very much. Actually panelook is where I found out about this particular panel. 800$/year is a reasonable price, but the problem is that even buying the panel and having a custom controller made for me is such a stretch to my budget right now, that I'm struggling not to hide this project from my girlfriend! Those 800$ would be a much easier investment if it wasn't for the fact that I learned what a vertical blanking interval is just a couple of weeks ago (just as an example). You can't imagine how hard it is form me to grasp even the surface of what I am reading! I should completely rely on someone else not being able to do anything. Nonetheless I'm willing to do it, but I think it will be a slower and less farsighted project (something like buy one component, wait for the money, buy the other one). I have already sent a mail to a distributor who says in the website to contact them if in need of a datasheet. Hopefully they will answer me soon. If the specs are right, the next step is looking for a decent quote!

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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by Chief Blur Buster » 11 May 2017, 16:43

matteo wrote:Thank you very much. Actually panelook is where I found out about this particular panel. 800$/year is a reasonable price, but the problem is that even buying the panel and having a custom controller made for me is such a stretch to my budget right now, that I'm struggling not to hide this project from my girlfriend! Those 800$ would be a much easier investment if it wasn't for the fact that I learned what a vertical blanking interval is just a couple of weeks ago (just as an example). You can't imagine how hard it is form me to grasp even the surface of what I am reading! I should completely rely on someone else not being able to do anything. Nonetheless I'm willing to do it, but I think it will be a slower and less farsighted project (something like buy one component, wait for the money, buy the other one). I have already sent a mail to a distributor who says in the website to contact them if in need of a datasheet. Hopefully they will answer me soon. If the specs are right, the next step is looking for a decent quote!
When your goal is "Helping make it possible" rather than "Capital Funding It All" it can be dramatically cheaper.

For example, over the last few years:
-- Publicizing LightBoost's usefulness for motion blur reduction
-- Blur Busters influence in Oculus founder's deciding to choose a rolling-scan OLED technique (this is little known)
-- Blur Busters directly convincing NVIDIA to add a "ULMB Pulse Width" adjustment to monitor menus. By direct communications by me.
-- Blur Busters directly convincing BenQ/Zowie to add strobe phase/strobe width settings. By direct communications by me.
-- Blur Busters creating of Strobe Utility for BenQ/Zowie monitors. (as a result of the above -- BenQ press release)
-- Blur Busters indirectly encouraging multiple manufacturers to add strobe modes to their displays (due to increased awareness)
-- Much indirect progress. LightBoost's popularity (single-handedly popularized by Blur Busters a few years ago) directly led to making ULMB become standard in many GSYNC monitors.

Things like this all cost us almost nothing (except time) -- as we're the only place online specially dedicated to "Better Than 60Hz" -- and had a tremendous behind-the-scenes impact on providing more flexible motion-blur-reduction.

We often have helped publicize users' creativity such as
-- Forum member StrobeMaster's work on displaycorner
-- Forum member zis's work on displays
-- Amazing overclock feats such as 60Hz->180Hz LCD overclocks
-- Inspiration of new careers for many visitors
-- etc

Occasionally, some people have teamed up together, or a member moved on to work for one of the big ones (e.g. a monitor manufacturer) or gotten bought out by a big company (e.g. Facebook buying Oculus, to my astonishment, albiet long after my involvement).

One possible 'cheap path' -- if you're just wanting to help make a dream display possible -- rather than bankrolling/capital funding the creation of a display.
-- Reach out to monitor manufacturers (they'll sometimes forward info)
-- Reach out to parties such as zisworks (display hackers)
-- Post in places like this (Blur Busters!)
-- Inform display engineers about new ideas on lowering persistence (not all of them understand how displays create motion blur)
-- Paid LinkedIn membership to more easily directly email people inside display manufacturers
-- Becoming member of SID.org to reach out to those display engineers more directly
-- Unusual attention-getters (e.g. FedEx instead of an email)
-- Etc.

Attempting to cheaply approach this via a monitor manufacturer
Imagine, what if Dell adds a 120Hz mode to their OLED -- how much effort would it be to hunt down the right contacts inside a display manufacturer, finally reach the correct contacts, and then successfully convince them to add a specific feature -- like we did for our advocacy on adjustable strobe pulse widths.

Attempting to cheaply approach this via third party modders
You want to also go via other routes (e.g. zisworks and other parties similar) where someone already sufficiently skilled might say, "...aha, I already have the skills to do this, just gotta buy the OLED...". It helps a lot if they're already familiar with Blur Busters, but not all of them are. They might be busy, but don't leave the stone unturned. Give them the link to this thread, for example.

Attempting to team-up
Finding someone with the skillz that's willing to help out for low cost (or free) in exchange for other things (e.g. free monitor, future cut of revenues, publicity, etc). If you have management skills, community skills, fundraising skills (IndieGoGo, etc), or you're in school deciding which elective to take (Management Studies, Economics, Programming, Electronics, etc), maybe Blur Busters has inspired you to take a specific path that while it takes many years to complete, helps achieve specific dreams.

There are many paths to take (possibly concurrently). Monitor manufacturers (in web logs) even constantly explore Blur Busters, even if for confidentiality reasons they may rarely reveal themselves. The information on the website may be mostly (good) popular science rather than full of math formulas, but more than half of display engineers do not understand the mechanics of display motion blur as well as we do!

The (accurate) popular science that Blur Busters publishes about display motion clarity, really helps many to understand how motion blur is generated -- the voodoo topic of display motion blur can be like quantum mechanics to some of them who just know good FPGA programming (far better than me) but nothing about how to remotely understand the mechanics of properly reducing motion blur (like I do!). The person born in the 1990s who grew up with 33ms LCDs and opaque programming APIs will often have less understanding of rasters/scanouts than the person born in the 1960s and doing Atari 2600 TIA programming of CRT days who had to be pixel-exact with scanout timings ("rasters" / "raster interrupts") just to generate graphics.

There are many wizards (like the people behind NVIDIA LightBoost) but we also see double-strobing monitors of multiple brands that have unremovable full-intensity double-image strobe crosstalks, that doesn't exist even in homebrew strobe backlights (hacker-built displays that surpass the strobe quality of certain manufacturer-built displays!).

Many display engineers are inspired by Blur Busters to make sure they read up "to avoid knowing less than we do", because it's competitively necessary. It's quite useful to remind display manufacturers that Blur Busters exists, and to read up our articles, in order to fill in knowledge-gaps. It's also useful to email all the OLED display manufacturers and panel manufacturers and give them a link to this article, some of them might even run with the ideas.
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matteo
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by matteo » 12 May 2017, 03:32

Thanks for the input. I'll think about it. Surely I was inspired by some of the topics discussed here on the forum. In fact, even though I started reading with the goal of getting my hands on a nice monitor, that has changed over time. I don't even know if i can afford something like that, but I couldn't stop trying to understand what can be done to make a monitor better. I'm not in school anymore but I'm thinking about facing these subjects in a more systematic way. I'd really like to understand how monitors work at a low level and being able to experiment with them. Maybe I'll look for some resources to study their internal architecture as well as electronics and low-level programming even if at at a very introductory level. Only experience I have is some simple programming, but nothing of this kind.

Edit:
I thought about what you said. I've decided that I want to learn how things actually work in order to be able to experiment a bit. I find it difficult to do something, even with the help of others, until I have a reasonable grasp of what we are talking about. I need confidence in my skills. I'd love someday to have the knowledge necessary to make my own contribution. Do you have any suggestion about where to get started?

cirthix
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by cirthix » 16 May 2017, 19:55

The problem here is lifetime and burnin.

OLEDs get dimmer as they age. Regular LEDs do too, but not nearly as quickly.

As you reduce active time, to keep the same light output, you must increase peak brightness. This is a MASSIVE problem with OLED.

Why? Because OLED aging is proportional to brightness^4. Do you want to see that in-game HUD all the time? Strobing aggressively can make that happen.

Now, OLED is a rapidly advancing field and I'm not actively part of it anymore. This information may be outdated. Source = coworker when working at Samsung display labs (mid 2014).

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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by Chief Blur Buster » 16 May 2017, 20:17

cirthix wrote:The problem here is lifetime and burnin.

OLEDs get dimmer as they age. Regular LEDs do too, but not nearly as quickly.

As you reduce active time, to keep the same light output, you must increase peak brightness. This is a MASSIVE problem with OLED.

Why? Because OLED aging is proportional to brightness^4. Do you want to see that in-game HUD all the time? Strobing aggressively can make that happen.

Now, OLED is a rapidly advancing field and I'm not actively part of it anymore. This information may be outdated. Source = coworker when working at Samsung display labs (mid 2014).
OLED still has this problem today, you can't use much boost on OLED, so you're right. Maybe, say, 1.25x or 1.5x boost for short periods, but that's just a guesstimate. For the most part, brightness will have to go down linearly with pulse widths for the most part.
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RLBURNSIDE
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by RLBURNSIDE » 05 Jun 2017, 16:00

I'm more in favour of boosting refresh rates of OLEDs past 120hz than reducing MB via cutting their lumens and pixel lifespans through low persistence, although I admit it certainly helps boost clarity for VR helmets.

I'd rather interpolated 240hz full-persistence with decent HDR, HDR is fundamentally antagonistic to low-persistence in terms of engineering goals. (cutting lumens vs boosting it for increased dynamic range).

What I'd find very interesting would be doing reprojection due to head movements inside the helmet itself, that way you could reduce MB + persistence and input lag too at least for gaze tracking. Although this would require pushing out the depth buffer to the HMD too. Maybe not...

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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by Chief Blur Buster » 07 Jun 2017, 12:23

Yes, HDR and strobe-based persistence-lowering can be diametrically opposing goals, given the lumen-output limitations of OLEDs. That said, the user can still switch beteen the two, or even adjust in a continuum (balance between HDR versus low persistence).

That said, persistence can be made dynamic (sort of like on a plasma or long-persistence CRTs) where dimmer colors has less persistence and brighter colors has more persistence. This would require an unusually different refreshing technique like multiple OFF-passes and realtime image reprocessing to have short persistence for dimmer shades. Several plasmas tended to roughly behave this way (more persistence for brighter colors) with more bright & spread-out subfield refresh cycles for bright colors.

In a simple form (soon-ish), a custom multipass OLED refreshing algorithm (e.g. multiple chasing OFF-passes that selectively turns off pixels) may be able to pull this off. In theory.

In a better form (5 years), another possibility is building time-delay automatic "OFF" transistors/switches into each pixel. The more persistence you want, the longer you command the pixel to stay on before it turns off automatically (without needing an OFF pass). Adding extra logic to every single OLED pixel would require a heavily custom-manufactured OLED panel since you wouldn't be able to do the persistence-lowering via the TCON (Timing Controller / motherboard of OLED monitor) like you could with rolling scans.

In a future-advanced form (10-20 year), there could be simple low-power GPU array built into the full surface of the panel, right behind the pixels! Processing for translation / interpolation / translation in a circuit layer behind the OLED pixels. Basically, the display would be one gigantic GPU running at low-power, dedicated to non-strobe-based persistence-lowering algorithms (translation / interpolation / reprojection / etc). Imagine, 1000fps-5000fps full-persistence zero-flicker VR using only a 100Hz video output from a PC or primary powerful rendering GPU...

Then you can have your HDR cake and eat low persistence too. You'd simply get more motion blur with brighter colors.
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by Chief Blur Buster » 19 Jul 2017, 14:50

Oh, by the way, there's an important caveat when multiscanning. If you do it wrong, it will sawtooth:

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(Sawtooth artifact caused by multi-scanning of the SAME refresh cycle -- more info in this thread)

To prevent sawtooth artifact problems caused by old-style multiscanning, (A) each concurrent scanout pass must be complete top-to-bottom, and (B) each individual scanouts must correspond to a complete, separate, consecutive refresh cycle (frame). To avoid the dreaded multiscan sawtooth, you must avoid multiscan of the same frame (refreshing the SAME refresh cycle in separate scanouts at the same time on different parts of the screen). Each scanout must be of separate frames.. That way, there can be safely be multiple scanouts concurrently on the same screen, with NO sawtooth artifacts at all.

Slower scanouts will have more skewing (e.g. See your computer monitor scan skewing here: http://www.testufo.com/scanskew ...) but this is mostly insigificant at 1/120sec scanout velocities. And we all know, that a minor skew is not nearly as noticeable as sawtooth.

Then you can 8-way multiscan the same 120Hz OLED, to achieve 1000fps@1000Hz with absolutely ZERO sawtoothing.
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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by life_at_1ms » 29 Dec 2019, 15:18

Sweet thread. I wonder if we can get some hobbyists who build stuff like this in here. If they pull it off in a reproducible way, well tested, reasonable assembly procedure - then it could be a sort of "build it yourself with this parts list & instructions + donation."

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Re: Custom OLED Rolling Scans -- Custom Built OLED Monitor

Post by Chief Blur Buster » 30 Dec 2019, 13:23

life_at_1ms wrote:
29 Dec 2019, 15:18
Sweet thread. I wonder if we can get some hobbyists who build stuff like this in here. If they pull it off in a reproducible way, well tested, reasonable assembly procedure - then it could be a sort of "build it yourself with this parts list & instructions + donation."
I have no doubt that it is probably possible with some passive matrix discrete LED grids, as a scientific experiment. You could even do it with a 32x32 Jumbotron LED grid which are cheap, you’d have to bypass its existing refresh electronics and control the row/columns directly. There are some that are passively driven for those hard-core experimenters.

You do want to avoid LEDs containing built-in chips such as WS281X (WS2811, WS2812, WS2813) and SK6812 chips, because those are chips built into LED lights (they’re amazing though — I use a 300 LED Neopixel-compatible LED ribbon to light up the Blur Busters office — it’s accent lighting dot-addressable like a single pixel row of a JumboTron). Neopixels are expensive, but dot-addressable 5-meter RGB LED ribbons are now available on eBay for only a few ten dollars each (60, 144, 150, 300 individually controllable RGB LEDs on a light ribbon). Unfortunatately those would not be suitable for these experiments because of the built-in chips on them.

However, the ones without chips, like this Adafruit 32x32 LED panel could be suitable for DIY hobbyist experiments of custom OLED rolling scans. Due to the speed of LEDs, it won’t “benefit” these over simply faster single-pass scanouts, but it can be a proof-of-concept that’s doable within hobbyist skills of a good microcontroller programmer.

It works best if you know FPGA programming, but one can still do it in slower-motion by subividing multiple Arduinos to control separate rows of pixels — treating the display as multiple separate thin-slice ultra-high-Hz displays.

The beauty is that the algorithms in this thread are very highly parallelizable (same concept as simple chips driving the separate cheap LED modules of a large modular jumbotrons), so you could pull off concurrent scanout experiments cheaply, by having one low-level RPI or Arduino per pixel row (32 Arduinos) instead of using an FPGA. Still doable on hobbyist budget using near-identical copies of software installed on each. So you can say goodbye to FGPA for concurrent scanout experiments.

Basically, you’d have a shared column addressor, but separate high-performance Arduino-compatible per row. Then load programs for 1-sweep, 2-sweep, 4-sweep concurrent-scanout programs.

Refresh rate multiplication is easy to achieve with some simple parallization-think, using lots of basic technologies that are basic concepts that are well written about decades ago.

The only thing missing is that the manufaturers haven’t yet added enough channels to their panels (e.g. 8 channel refresh logic). Those will benefit screens that require more time per pixel row to refresh (e.g. LCDs).

But at the small scale, 32x32 LED screens like these are perfect for hobbyist homebrew refresh-rate multiplication experiments!

Click Here to go to Page 3 of Custom OLED Rolling Scans
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