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Linux strobe utility

Posted: 09 Apr 2014, 08:57
by fhunleth
For the Linux users out there who'd like to tweak the BENQ Blur Reduction settings without switching back to Windows, I wrote a simple command line utility to help do this. You can find it at https://github.com/fhunleth/blstrobe. It is nowhere near as user friendly or polished as Mark's Strobe Utility, but I hope that some of you will still find it useful.

Since I only have a XL2420Z, the monitor detection code may incorrectly fail your display. For now, you can use the "-f" parameter (force) to send the commands to your monitor anyway. But please file an issue on the project's page on GitHub and include your monitor's parameters so that I can fix it.

Re: Linux strobe utility

Posted: 09 Apr 2014, 09:52
by Chief Blur Buster
Nice work! Our fellow Linux users will find this very useful.

Could this be made to work in MacOS Terminal too?

The minimum strobe duration is 0.5ms, all settings below 0.5ms automatically rounds up to 0.5ms. You'll notice no brightness change when you try to go below 0.5ms.

Re: Linux strobe utility

Posted: 09 Apr 2014, 10:24
by RealNC
Chief Blur Buster wrote:Could this be made to work in MacOS Terminal too?
It uses the Linux i2c kernel API. I doubt that Apple supports any Linux APIs ;-)

Re: Linux strobe utility

Posted: 09 Apr 2014, 10:38
by fhunleth
Right. I'm using the Linux i2c-dev kernel driver. This page suggests that there's hope for Mac users: http://www.paintyourdragon.com/?p=43. I'm don't have a Mac to try it out, though.

Also, regarding minimum strobe duration, I actually can see a difference between 0.167 ms, 0.334 ms, and 0.5 ms on my monitor at 60 Hz. I haven't tried other video modes, so maybe there's something inconsistent in the support.

Frank

Re: Linux strobe utility

Posted: 09 Apr 2014, 12:16
by Chief Blur Buster
fhunleth wrote:Also, regarding minimum strobe duration, I actually can see a difference between 0.167 ms, 0.334 ms, and 0.5 ms on my monitor at 60 Hz. I haven't tried other video modes, so maybe there's something inconsistent in the support.
Hmmm, I'm going to have to investigate this further. There might be a subtle difference between my V2 monitor and the official V2 firmware upgrade that got released. Thanks for informing me!

Re: Linux strobe utility

Posted: 09 Apr 2014, 12:53
by masterotaku
Chief Blur Buster wrote:
fhunleth wrote:Also, regarding minimum strobe duration, I actually can see a difference between 0.167 ms, 0.334 ms, and 0.5 ms on my monitor at 60 Hz. I haven't tried other video modes, so maybe there's something inconsistent in the support.
Hmmm, I'm going to have to investigate this further. There might be a subtle difference between my V2 monitor and the official V2 firmware upgrade that got released. Thanks for informing me!
Yeah. I'm using the service menu, and with the lowest strobe duty, I think the alien invasion is completely blur free at 3000px/s. The next step, 3840px/s, is too fast for my eyes, I can't follow the aliens properly.
As the setting is called strobe duty, and it ranges from 001 to 030, I didn't know how many miliseconds corresponded to each number. At high frequencies, I use 003 (0.5ms), and 1920px/s is perfectly crisp, but there's a bit of blur at 2400px/s. This monitor is amazing at this.

Edit: seeing that it ranges from 0.167ms to 5ms, that corresponds to the 30 steps of strobe duty :D .

Re: Linux strobe utility

Posted: 09 Apr 2014, 13:10
by Chief Blur Buster
Now we need manufacturers to build brighter backlights, for brighter strobe flashes, so we can have 0.5ms persistence with the brightness of 3ms-5ms persistence. :)

I am surprised you are still picky about sub-pixel amounts of blur at 0.5ms persistence. But I'm not surprised that some people can still see a slight bit of motion blur at this level since at 2000 pixels/second, you will get 0.5/1000ths of that in motion blur = 1 pixel of motion blur.

Also, the strobe length seems to vary depending on the current timings. I calibrated/measured the 5ms strobe length (via photodiode oscillscope) during the maximum setting, while using the Vertical Total 1350 tweak (to hide LCD GtG transitions inside a large vertical blanking interval). If you do not do the VT1350 tweak, the 5ms setting in Strobe Utility seems to be closer to 2.5ms. I'm unfortunately unable to detect if the system is running the VT1350 or VT1500 tweak, and recompute the strobe lengths, as the monitor is not reporting information (If anyone knows Windows API's that can read advanced Custom Resolution timings information on any graphics card, I'd love to know -- send me a PM). The strobe lengths are measured differently depending on the size of the blanking interval (normal versus VT1350 tweak).

Go to 120Hz, with the Vertical Total 1350 tweak.
Now, adjust strobe length while viewing http://www.testufo.com/blurtrail#separation=150
You will clearly see Blur Busters' "Law of Persistence" in action:
1ms of persistence (strobe length) equals 1 pixel of extra motion blur during 1000 pixels/second motion.
(Assumes consistent motion; framerate == refreshrate == stroberate)

P.S. If anyone here knows how to read custom resolution data for the current video mode (e.g. to detect whether the VT1350 tweak is currently being used or not), I'd love to know. So I can modify Strobe Utility to display more exact, accurate values for situations where the VT1350 tweak is not being done.

Re: Linux strobe utility

Posted: 14 Aug 2015, 00:08
by forivall
I can confirm that this tool works with the 2411z, and I submitted a PR for built-in support: https://github.com/fhunleth/blstrobe/pull/1