<Advanced RTSS Scanline Sync Question>
To other readers: This reply is not relevant if you don't use RTSS Scanline Sync + Quick Frame Transport You can instead use the easy factory PureXP+ modes instead.
No, it doesn't mathematically work that way.ELK wrote: ↑07 Apr 2020, 02:13Wow I've always pushed my tear line DOWN into the vblank (for example 1090 on a 1080p screen, instead of -10 or -50) Would this add an extra frame of input lag >.< You could edit the photo that says put RTSS tear line hear to mention ABOVE the frame with a negative number.
It's a total wraparound, look at the filmreels, refresh cycles are metaphorically an infinite loop. The latency is related to the ratio between VBI size and visible vertical resolution.
-- Which means when you have a small VBI, the latency is almost the same regardless whether you push the tearline above top / below bottom.
-- But if you have a large vertical total, you have noticeably lower lag if the tearline is just above top edge rather than bottom edge.
-- Moral of the story: Frame slices are independent gradients. The latency is always lowest in the pixel row immediately above a tearline, and the latency is always highest in the pixel row immediately below a tearline. In between two tearlines is a linear latency gradient. This even applies to tearing in the VBI (tearing doesn't exist in VBI, but you can still pretend they exist -- the math formulas for latency gradients are identical when you pretend there's a tearline on any VBI scanline beyond edge of the screen).
Mathematical Example: If your VBI is 420 pixels tall and your Active is 1080 tall (Vertical Total 1500 as an example, creating 1080 + 420), then 420/1500ths of a refresh cycle of latency adjustability occurs with a large VBI. Your worst-case lag offset is the tearline pushed just below bottom edge. Your best-case lag offset is the tearline pushed just above top edge. Your exact lag will depend on the "virtual tearline" within the VBI. You just have to pretend VBI is like extra "hidden computer resolution" that reconnects the bottom edge of the screen back to the top edge of the screen, in a continual looparound manner. VT1500 means your video cable is transmitting 1500 pixel rows for 1080p, of which 1080 rows of pixels are visible and 420 are blanking interval (VSYNC, VBI).
VBI = Vertical Back Porch + Vertical Sync + Vertical Front Porch.
Usually VBI is a tiny sliver (like photo of analog VSYNC like the black bar on 1970s analog TVs rolling with VHOLD). But the VBI can be huge (large vertical totals).
Once you understand this diagram better, please look at the PureXP+ Quick Frame Transport Trick filmreel scanout diagrams again -- in order to understand better -- and ask latency questions based on tearline position within the filmreel diagrams.
You can't modify numbers willy-nilly.ELK wrote: ↑07 Apr 2020, 02:13Increased the vBlank in strobed mode will push the strobe cycle earlier resulting in decreased input lag but while the backlight is on it will be showing more of the transition that strobe mode is designed to hide. I've tried it and it looks HORRIBLE. I wouldn't suggest this. Maybe a small tweak would be good though.
One have to understand exactly what each number does in Custom Resolution Utility. Most people do not know what a "Horizontal Front Porch" purpose is for, nor what is a "Pixel Clock". The strobe backlight has specific timing keys and the use of random vertical totals can improve or worsen strobe crosstalk. A CRU tweaking technique that works on say, vendor X (i.e. BenQ) may fail on vendor Y (i.e. ViewSonic) and vice-versa.
But fortunately, if you already have the new firmware, and you use only exactly only the numbers that I posted here, the crosstalk looks approximately the same (when using the new firmware), while you gain the ability to massively reduce the input lag of a "VSYNC ON lookalike" (RTSS Scanline Sync).
To other readers: This reply is not relevant if you don't use RTSS Scanline Sync + Quick Frame Transport You can instead use the easy factory PureXP+ modes instead.
</Advanced RTSS Scanline Sync Question>