Naveronasis wrote: ā09 Jun 2021, 09:19
I saw you can get older 1080p 3 chip dlp refurbished pro models on eBay around 1200 but the bulbs for those can be 300 bucks+ so im not sure your really saving money.
Currently, DLP makes poor CRT emulators at this time due to temporal dithering
DLP is nice for movies (I own a few DLPs myself) and they are Right Tool for Right Job. But not as CRT replacements currently.
DLP is temporally dithered so they don't become low-persistence as easily as LCD because as soon as you time-division the frames of a DLP, going 25% persistence on a DLP often creates a situation of 25% of the color depth because you have 25% of the dither time.
Now, trying to do 10% persistence on a DLP produces only 10% of the color depth. For example, a single DLP chip needs 1440Hz 1-bit (mirror toggling 1920 times per second) to produce 60Hz at 24bit color (24x60 = 1440). Three chipping this improves this quite a bit but it's still only 24bit per color channel per refresh cycle. Chopping to 10% persistence will only do 2.4 bits per color channel per refresh cycle -- only two and a half toggles of a mirror per refresh cycle. Ouch. Holy color depth loss!
There are faster DLP chips (1920Hz and 2880Hz I believe) but still not nearly enough to preserve full color depth during CRT-motion-clarity strobing of a DLP.
DLP will not easily match CRT motion clarity without artifacts without using 24 DLP chips simultaneously generating non-serialized color 24-bit depth. 3 chip DLP is nowhere near enough to get CRT motion clarity without color-depth-reduction artifacts of some kind since you're still temporally dithering.
Since the sample-and-hold effect requires much briefer persistence than the human flicker fusion threshold, a possible optimization is eye-tracking-compensated temporal dithering algorithms, and/or potentially pixels too tiny to see temporal dithering in (e.g. sitting far away from a true-4K non-pixel-shifted DLP chip). Major color depth improvements (And elimination of plasma-style contouring) occur if there's fancy eye-tracking-compensated temporal dithering algorithms, which would require an electronic eyeball-motion-sensing device and some really fancy algorithms. But that's quite some Rube Goldberg overkill just to eliminate visible temporal dithering in all possible eye-pursuit situations (including stationary-gaze-on-stationary-display, stationary-gaze-on-moving-display, moving-gaze-on-stationary-display), for situations where you want to do things like spread color depth artifactlessly over multiple refresh cycles.
Anyway, surprisingly, LCD performs better because of temporally-complete instantaneous color depth that can be more easily time-divided (aka strobing). So briefer strobes don't trunctate color depth like they do on DLP.
A cherrypicked fast-GtG LCD/LCoS projector + custom overdrive tweak (could be GPU-shader based if the projector electronics have no LCD overdrive) + external mechanical strobing, actually can outperform DLP in persistence.
LCD overdrive is simply a lookup table A(B)=C lookup table formula explained at
How LCD Overdrive Works (about 3rd post). Where A is the previous color (pixel on previous refresh cycle), B is the next color (pixel on current refresh cycle), and C is the resulting overdriven color (for one refresh cycle) to speed up transition from greyscale A to greyscale B. Pixel greyscale intensities are mapped to voltages, so it is easily done at the software level / firmware level / GPU level. ATI used to do this with "ATI Radeon Overdrive".
While it may be months or years, we're eventually awaiting a rumored (if true) upcoming open source virtual display driver enhancement to an existing frame processor engine (it's one of those SweetFX / ReShade engines). Adding refresh cycle granularity processing to one of those engines in addition to frame granularity processing, now makes it possible to add reliably superior software-based overdrive to LCD displays (including cheap 1080p LCD projectors) without overdrive, or has inferior overdrive, albiet it will rob a % of GPU processing time. Not a bad tradeoff if you already have a powerful GPU. I expect a bigger acceleration of Blur Busters maker projects and open source projects that helps speed up the refresh rate race to retina refresh rates.
Overdrive is something that needs to be done at the refresh cycle granularity rather than the frame granularity. Meaning overdrive only occur only on the changed pixels on the first refresh cycle immediately after the previous refresh cycle.
TL;DR: Well tuned LCD outperforms DLP when doing CRT simulation
Also:
Mythbusting Modern VR
Just so you know, modern VR is more eye-comfortable and not roller coaster anymore. The "Comfort" rated Oculus apps (like the Alcove virtual beach) are 100x better and less dizzying than Google Cardboard roller coaster demos.
And now much less dizzying than 3D glasses at the movie theater -- VR has now become the world's most comfortable stereoscopic 3D, thanks to the breakthroughs of the last 5 years.
VR headsets can also simply be used to put a simulated CRT motion-clarity monitor on a virtual desk. In the case of Quest 2, you simply run the "Virtual Desktop" app, make sure your PC refresh rate and Quest refresh rate is identical. Then the PC will stream the Windows desktop picture (over WiFi) from your PC to the VR headset, so you can play any 60fps content or videos or emulators, Even running MAME HLSL looks even more accurate because CRT's lack of motionblur is much more accurately simulated than on a physical desktop LCD (due to the superior calibration of the Oculus LCD). And movements are now perfectly flawlessly sync'd now with no stutter or lag. Look down and you see a virtual computer chair. Look around, and you see a virtual computer room. Lean down and you see the bottom of a virtual computer desk. Look in front of you and you see a 0.3ms persistence simulated desktop computer monitor that can do CRT motion clarity when playing YouTube videos. Proper modern VR (like Rift, Vive, Quest) is much closer to a Holodeck nowadays than a toy VR. There's perfect 1:1 positional sync, which is why you can look at the bottom surface of your virtual computer desk simply by crouching down and looking underneath, just like a real computer desk.
So with the apps that maintain 1:1 perfect real:VR sync, there is zero dizziness at all, and is 100x more comfortable than Real3D Cinema Glasses. It's currently the most comfortable true stereoscopic computer generated 3D known to humans; and is practically 100x closer to a Star Trek Holodeck now. The Quest 2 is also easier to set up than an iPad, not requiring external sensors anymore -- being a self contained unit -- to the point where one was mailed to a nursing home (almost jails last year during COVID, essentially) -- and a 70 year old was able to set it up by himself and enjoy playing virtual chess on a virtual table with faraway family members, speaking to each other as if they were simply sitting across the table. Quest 2 has a built-in GPU almost as powerful as a GTX 1070 and has a in-VR app store that runs on its Snapdragon, so it's a one-piece VR headset with powerful graphics that does not require a computer.
I know you probably don't want to do VR, but I just wanted to allay any old-fashioned fears of not wanting to try VR, because you became sick visiting a 3D movie at a movie theater. Modern VR is no longer like that and comfort has gone beyond that factor. The last 5 years have been nothing short of incredible for VR innovations. Some headsets are no longer complex and no longer needs computer -- and the Quest 2 includes what is tantamount to a very powerful smartphone GPU built into it, so it's completely self contained plug-and-play with no wires and no external sensors, compatible with seated, standing, or roomscale play. Even if it is only used about a few hours a week, it's a pretty neat experience feeling like you're inside a Holodeck.
About 50% of people I know who buy an Oculus Quest 2 are non-gamers, and most of them are older than 50 years old. They just run a few non-traditional-game apps such as "Alcove" where you can play checkers or chess on a virtual table in a beachfront house -- very simple VR experiences that feels like you're actually somewhere else other than your current home.
You don't have to try VR, but I reply only because you said "But not VR". I just wanted to give you a heads up to erase some old VR assumptions from older "toy" VR technology.
Obviously, if you dislike Facebook Login, that is a problem (legitimate, I don't like that feature).
But, this $299 headset is practically a $3000 (five years ago) worth of technology at one-tenth the price -- it's amazing how much tech is crammed into it. In fact, just the screen alone of a Quest 2 is probably theoretically worth $300 to a CRT enthusaist (throwing away the Quest 2's GPU). Or even the Quest 2 GPU alone in this inflated market (worth $300 at its horsepower), throwing away the screen and the rest of the VR headset guts. But there's also the additional tech/sensors/controllers too that completes the self contained VR experience. It's a bona-fide self contained computer with powerful GPU and AI that is doing perfect zero-stutter framerate=Hz sync in almost all the apps in the Oculus App Store. You've seen what 60fps looks like on a CRT. Now imagine all games running guaranteed framerate=Hz because it's an app store requirement!
Also, it (the "Guardian" safety system) uses near-photogrammetry AI to alert you before you bump into your furniture! Which means if you step a little too close to your furniture, the room becomes transparent to you (there's cameras on the VR headset), allowing you to see your furniture before you walk into them. It generates better graphics (without a computer) than most iPhones and Androids for examples, and it can do perfect framerate=Hz permanently in all games (The in-VR Oculus App Store made that a
mandatory app store approval requirement to reduce motion sickness). You just put on headset, surf the in-VR app store, download the apps, and run the apps, all self contained nowadays. The Guardian system is actually cutely inspired by a Star Trek holodeck -- it displays a 3D blue grid of your room shape (overlaid on the VR app or VR game or whatever you're running) if you're within about 2 feet of the edges (adjustable alert distance), well before the headset "goes transparent" (displays stereoscopic video of the room via the VR headset's cameras) if you continue approaching the grid.
The guts of an equivalent of a high end Samsung Galaxy S10 smartphone is completely embedded into the Quest 2 -- but with a much superior CRT-matching display. And also goodbye to a computer as a requirement to run the headset (but computer can still optionally be used, like Remote Desktop, or for optional PC-generated VR streamed to the headset). 60fps YouTube videos can be directly streamed to an IMAX-sized CRT-motion-clarity display that you need to lean upwards to see the top edge of (Quest2's YouTube app supports a 60Hz strobe mode on Quest 2 with motion clarity better than an average CRT tube). The simulated display size is adjustable in settings, from small desktop size-ish, to gigantic IMAX size. Or just install your favourite .mp4 or .mkv file and play. The GPU is powerful enough to generate 90 frames per second of 3D for each eye in real time, as you move 6 degrees of freedom, in perfect 1:1 movement sync, with its built in array of built-in movement sensors. It now even has hand-tracking AI so you actually see your hands while in certain VR apps, if you don't want to pick up the controllers.
In this case, Quest 2 is a "Standalone" (built-in GPU), and only the world's 2nd
standalone headset capable of doing
all 3 modes (sitdown, standing, plus now the very Holodeck-style RoomScale). RoomScale is now made safe with that new AI photogrammetry-like safety protection in preventing you from bumping into furniture -- never before done until Oculus pulled it off in a standalone WITHOUT needing an external computer/GPU nor clumsy external sensors; turning it to the world's easiest/cheapest Holodeck as of 2021).
Heck, Quest 2 even works with RoomScale up to 25x25 so you actually run and throw bowling balls in the VR bowling game, with perfect non-dizzying 1:1 vertigo sync. If you have enough room to do a running-area, "Premium Bowling" app on Quest 2 is far, far superior than Nintendo Wii bowling. Essentially, you're truly immersed into a Holodeck of a bowling alley, with perfect 1:1 roamaround movement sync, for chrissakes -- you can randomly walk around your bowling area. (Assuming your physical room is big enough to cover the necessary running throw area without activating the Guardian safety). I don't even have that space, but I was able to temporarily use my backyard at night as a bowling alley (Quest 2 fully bult-in self-contained headset sensors doesn't like direct sun but works fine in a 16-watt-LED-lit backyard -- the cameras doesn't need more than a single bright LED bulb to light up your yard). Or just visit your apartment's unused conference room for a couple rounds of bowling. Or whatever -- the Quest 2 travels well.
Anyway...
This now-mostly-automatic RoomScale safety is possible because Quest 2 has four externally-pointing cameras to allow the room to become visible to user until you start your VR app, aids in semi-automatically mapping the clear room floor you can safely roam on, and the cameras also helps alert you when you're too close to the walls/furniture in your room -- the VR app automatically fades to transparent view of the room as you approach the edges of safety.
This shockingly simplifies the Holodecking workflow to simply putting on the headset and following its one-time in-headset VR setup wizard (about 10 minutes). Thereafter, the VR experience is instantaneous (1-second wake-from sleep, or 5-second Oculus-custom Android AOSP Linux bootup on the Quest 2 CPU-GPU) as putting on the headset -- it even AI-recognizes the room you're standing in and automatically loads its memorized layout to prevent you from bumping into the furniture. Also it travel well to visiting family or a different room you've never used the headset in -- if Quest 2 it does not recognize the room, it takes only 10-15 seconds to set up the specific room's "anti-bump-into-furniture" safety protection system (called the "Guardian"), and your VR experience resumes.
None of the "lots of wires, complex setup" shit of a 2016 VR headset, because of "no computer, no wires, no fuss" experience enabled by the incredible tech crammed into one self-contained unit.
VR aren't dizzying roller coasters if you don't want that. You can just run those apps that lets you sit on a beachfront chair to get away from your covid locked-down house. Or an app that puts a virtualized CRT-motion-clarity display on in virtual computer room. All with 1:1 perfect VR-to-realworld movement sync (tilt head sideways, tilt head upsidedown, lean underneath a desk, walk around the computer desk, lean forward to stare closer at virtual computer display). You can even avoid the 360-degree video gimmicks, or the fast-action videogame apps, and stick to only a few apps (like exploring ISS space station or spacewalking just outside ISS floating above planet Earth).
P.S. I helped tip some dominoes on VR innovations, see
How Blur Busters Convinced Oculus Rift To Go Low Persistence. Achieving framerate-refreshrate locked low-persistence (CRT motion clarity) turned VR from a toy into a Holodeck.
But I just wanted to mythbust some common reasons for not liking VR ("VR is dizzier than 3D movies" -- no longer true) ("I tried a smartphone inserted into a cardboard headset and it looked bad") ("I got super-dizzy when I tried a demo VR headset at Best Buy with that flying spaceship game"). One can stick to those "Comfort-rated" (Oculus App store has comfort ratings) 1:1 movement-sync apps that pretty much has no headaches at all for majority of population (as long as you're not flicker sensitive at 72Hz, 90Hz or 120Hz, since headsets need to flicker like a CRT to eliminate motion blur). It's fine to handwaved VR off as a gimmick due to prior experiences, but I wanted to give you a heads up of some rapid tech advancements that occured in the last 5 years, and it's why Quest 2 is apparently selling fast like Nintendo Wii's.
About running Remote Desktop on VR: Also, if you use a cable instead of WiFi, it is actually capable of E-Cinema quality video decompression at approximately 500 megabit/sec H.264 or H.EVC compression, so the Remote Desktop is perceptually loss less (artifactless computer desktop). However, I hate the cord, so I am able to do approximately ~100 Mbps (far better than BluRay compression) of 1080p90fps streaming over WiFi 6 between my PC and Quest 2 via Virtual Desktop, when doing my "IMAX-sized CRT monitor emulation" task via Remote Desktop. You do want to make sure your PC has an NVIDIA GPU if you want to blast E-Cinema light compression between PC and Quest 2 for as perceptually-lossless-compression of a Remote Desktop to the point where it feels as if it's a local monitor.
Anyway, it's an awfully lot of tech being mainstreamed into an all-in-one VR headset.
Now, there are other legitimate reasons to not liking VR obviously. That Facebook login (arrrrgh). The default strap comfort (though it's removable and there are 3rd party foam-padded straps that are better). Headset weight, though Quest 2 is surprisingly light (lighter than an iPad Mini despite outperforming the GPU of an iPad Mini). Incompatibility with your eyeglasses prescription (though there's partial solutions; like the custom spacer). Flicker discomfort (but that probably doesn't apply to a CRT enthusiast). Etc.
Honestly, Metaphorically, Google Cardboard is the Atari 2600 video game crash in crapware experience. Quest 2 is the Nintendo Quality Seal of Approval, in quite the quality upgrade over yesteryear VR.
Now, Quest 2 is not all unicorns and rainbows. That goddamned Facebook login. Ya. And obviously it has annoying limitations (e.g. Netflix stuck at 480p due to lack of the necessary HDCP-style copy protection), but that is apparently solved by side loading the Android Netflix app (via SideQuest) -- sideloaded Android apps show up as floating rectangles approximately virtual 100 inches in diameter placed about 8 virtual feet in front of you. They stay stationary in 3D space, so they are above you if you look down, and below you if you look up. Quest 2 is a custom Android AOSP implementation, but as long as your .apk file is not using too many Google-authenticated services, sideloaded Android apps work fine as floating-windows-in-3D-space when run on them. And whatever motion in those Android apps are also nicely CRT motion clarity -- so you can run your favourite Android-based emulators too if you want a computerless method of running retro games on the Quest 2... (installing emulator ROMs directly on the Quest 2 headset). RetroArch Android works well on Quest 2. One problem is the default 72/90Hz refresh rate, so you have to force 60Hz via the SideQuest settings (SideQuest is an application sideloader for Quest 2 -- found at
www.sidequestvr.com but it has neat features like forcing a refresh rate), to fix the emulator stutters (framerate=Hz), then it looks beautiful.
There are developments to turn VR into simpler Oakley-style sunshades over the next ten years. But at least now you know why Quest 2 is the current gold standard in an "iPad-easy" VR headset that actually has great non-dizzying graphics as well some of the best CRT motion capability I've ever seen in an LCD (running Virtual Desktop inside VR to view an IMAX-sized CRT tube).
Hopefully this gives you a perspective of a specific VR use-case for you (putting a IMAX-sized CRT tube 10 meters in front of you, even if you live in a tiny apartment), which is precisely why I mentioned VR as a potential suggestion.
This gives you context of why I suggested Quest 2 to you as a CRT enthusaist -- it can just simply merely be the medium/glasses that puts a virtual CRT (that isn't actually there) in front of you that you can run an emulator on more realistically than most desktop LCDs, and/or watch 60fps sports material with better motion handling than any plasma/LCD you've ever seen. Etc.