All of this is normal.
You are just unfamiliar with how a DLP refreshes.
It does
NOT have such a thing as a traditional scanout.
And yes, camera sensor scan speed can be a factor.
RealNC wrote: ↑13 Jun 2021, 16:08
It's complicated with applications that don't have a true fullscreen mode. Not sure if browsers do that now or not. But you can try and find the application profile of your browser in the nvidia control panel's 3D settings. Find the entry there for Chrome or Firefox (or whatever browser you're using) and see if vsync is forced there for that profile. Force it to off, restart the browser, and see what happens.
RealNC is right, since this distorts testing as TestUFO is designed for VSYNC ON browsers.
Do this, don't use VSYNC OFF with browsers. Fix TestUFO first before reading the below. TestUFO problems are unrelated to DLP. Make sure TestUFO Hz equals Windows Hz. Then once you fixed that, read onwards:
LagIsTooDamnHigh wrote: ↑13 Jun 2021, 08:52
Rotating the camera 90° degrees showed that the screen seems to update in different directions depending on the orientation of the camera, so apparently I am not recording scanout of the projector, but scanout of the camera?
Correct, scanout of camera.
The
www.testufo.com/scanout is useless without a camera capable of 1000fps -- try a Samsung Galaxy S9, S10 or S20 in Super Slo Mo mode.
LagIsTooDamnHigh wrote: ↑13 Jun 2021, 08:52
A) is the projectors scanout so fast that I can't record it at 960fps? Does the DLP switch so much faster? Is my Note10+ @960fps too slow?
DLP is a global refresh technolgy that refreshes a 1-bit refresh cycle in 1/1440sec to 1/2880sec.
DLP does the following:
1. It buffers the refresh cycle from the cable, and then;
2. Temporally separate the frame into about 24 to 48 separate 1-bit refresh cycles that are displayed in a ultrafast 1/1440 to 1/2880sec sweep as a 1-bit monochrome
3. The DLP refresh flashes a different 1-bit refresh cycle every 1/1440sec to 1/2880sec.
Depending on the DLP chip, the DLP is outputting about 960, 1440, 1920 or 2880 different 1-bit pictures per second, as a method of temporally dithering. The mirrors of a DLP chip is always binary (only ON, or only OFF) so you're seeing effectively greyscaleless monochrome refresh cycles in fast 1/1440sec or 1/2880sec camera exposures.
This is also done in sync with the color wheel, so it will be focussing on 1-bit red refresh cycles, or 1-bit green refresh cycles, or 1-bit blue refresh cycles. It may even refresh in sync with the color wheel boundaries, as the color wheel boundaries sweep past the chip, or simply blackframing them out until the colorwheel boundary is past -- different DLPs do different algorithms for this.
LagIsTooDamnHigh wrote: ↑13 Jun 2021, 08:52
B) Why can't I record tearline/multiple frames at once despite VSYNC OFF? Does the projector perform additional buffering? (it seems like at least a whole cycle on the color wheel always belongs to the same frame)
For a commodity consumer camera or smartphone to properly capture a DLP projector and its tearlines, you must, must, must, must, must, must, must, must, must, must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must must, must, must, must, must, must, must, must,
MUST configure camera exposure to EXACTLY the refresh cycle or a multiple thereof (e.g. 1/60sec camera exposure for a 60Hz refresh cycle, or 1/120sec camera exposure for a 120Hz refresh cycle). Don't let the camera set exposure.
Now, that's probably not your goal, though (I just say this as camera science in the age of a display requiring temporal dithering). If you capture DLP too fast, you're capturing fragments of DLP's temporal dithering, resulting in distorted color. But the photos become perfect color (with tearing artifacts visible), once your exposure is a full refresh cycle. Even if the timing of camera exposures is not perfectly aligned with timing of refresh cycles (that creates potential artifacts, but far less than interrupted temporal color, thanks to too-short camera exposure), it should still be able to make tearlines visible.
If you are capturing pursuit camera images of a DLP, that's okay as long as it's a multiple thereof (exactly 4 refresh cycles -- e.g. 1/15sec camera exposure for a 60Hz pursuit camera capture of
www.testufo.com/ghosting via the hand wave smartphone method described in the pursuit camera forum).
If you are capturing VSYNC OFF tearing on a DLP, you will capture it successfully for fast horizontally scrolling motion (try 10,000 pixels/sec panning speed in your game, like pegging a joystick while taking a picture). As long as your camera exposure speed is set correctly --
never faster than a refresh cycle for this specific kind of situation.
LagIsTooDamnHigh wrote: ↑13 Jun 2021, 08:52
C) Is it even possible to reduce latency by turning VSYNC OFF and increasing framerate or does this not apply to DLP projectors?
VSYNC OFF is always lower lag for DLP projectors, but the latency will feel odd because VSYNC OFF is scanout-following, while DLP buffers-and-globally-refreshes (in repeated ultrafast 1/1440sec to 1/2880sec 1-bit scanout, as part of its art of temporal dithering). This means top edge and bottom edge will have different latencies, since VSYNC OFF feels better on synchronous-scanout monitors like LCDs and DLPs. To compensate for this lag-ugliness partially, get a 240Hz DLP such as Optoma. Then this reduces the buffering penalty to 1/240sec.
VSYNC OFF is at the signal level so it's already delivering fresher pixels sooner to the display, no matter what odd things a display is doing. However, whether it's a superior lagfeel (top=bottom) or an odd lagfeel (top unequal bottom) despite being lower lag as before, it is up to you to decide if you prefer that specific latency.
This may be why you are erroneously claiming "Unable to reduce input lag with VSYNC OFF" with DLP, it's simply because you're getting erratic amounts of latency reductions. Most gamers prefer higher-but-consistent latency rather than erratic-but-lower-latency.
Also, Leo Bodnar is a "60fps VSYNC ON" latency tester, and there is no VSYNC OFF latency test mode in a Leo Bodnar, so it cannot be used to benchmark VSYNC OFF latency improvements.
LagIsTooDamnHigh wrote: ↑13 Jun 2021, 08:52
Would love to hear some feedback from the experts. This topics seems to be such a rabbit hole that you need years of experience to grasp all the details involved.
Kind of. But it's not too difficult to understand once you've got a basic understanding of all the articles at
www.blurbusters.com/area51 which is still easier to study than say, first-year University math. Then begin to understand the scan conversion thing at
Quick Frame Transport, especially fixed-scanrate LCDs versus variable-scanrate LCDs (why certain 240Hz LCDs have high 60Hz latency).
Then you understand there's two separate scanouts involved -- the signal scanout -- and the panel scanout -- and they can be different velocities. And scan conversion becomes necessary, which means buffering a different-speed scanout (signal to display memory), then played out to the display pixels at a different scanout velocity (display memory to actual pixels).
Then, you simply picture DLP projectors as ultra-high-Hz 1-bit 1440Hz displays that needs to buffer a slow-scanning signal (60Hz, 120Hz, 240Hz) before the DLP projector electronics can begin refreshing at 1440+ 1-bit refresh cycles per second.
A minimum of 1440 refresh cycles is needed for DLP to generate 24-bit 60Hz, because 60 x 24 = 1440. And as a result, DLP scanout is ultrafast sweeps (1/1440sec) too fast for anything but an expensive Phantom Flex camera to capture.
For a typical consumer camera/smartphone, you can essentially only capture aggregate behaviors (like VSYNC OFF tearing) by having camera exposures equalling a refresh cycle.
One of your band-aid DLP latency solution to scan conversion latencies and the latency gradient (asymmetries in top/center/bottom), is to speed up the signal-side of thing closer to the DLP scanout speed. Such as the 240Hz Optima (inexpensive) or the 480Hz Christie (expensive).