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Low persistence in gearvr apps

Open dattanand opened this issue 8 years ago • 23 comments

I guess GVRF apps also run in low persistence mode of oculus. is there any way to disable it in GVRF or using any Oculus API. Is it possible in latest SDK? I could see one old thread here. https://forums.oculus.com/developer/discussion/14874/any-way-to-disable-low-persistence.

thanks dattanand

dattanand avatar Jul 13 '16 13:07 dattanand

I think this happens automatically for any vr app. Not seeing any apis in the mobile sdk for dealing with it.

liaxim avatar Jul 13 '16 14:07 liaxim

@dattanand Do you think there is something that we could do?

liaxim avatar Jul 14 '16 16:07 liaxim

If its possible to disable it, it will reduce flicker in certain cases I believe and the motion blur is not noticeable unless the scene is bright. actually we are also exploring if such change in android framework if not provided by mobile SDK can solve the same issue.

dattanand avatar Jul 15 '16 05:07 dattanand

I want to vote for this. For some people (including me), this kind of flickering makes it impossible to look at the screen, I get eye strain almost immediately, and it's very obvious (I guess it's 60hz?) I tried searching and didn't find any way to disable this "feature", unfortunately. Samsung should make it possible to disable this flickering (even if hidden in options somewhere)

sp-1234 avatar Jul 25 '16 11:07 sp-1234

This is quite terrible on GearVR with my S7. If I use the GearVR with cardboard apps the image is much clearer, cleaner and sharper, and there is no flicker at all. I cannot understand, why Samsung won't allow this to he deactivated!

ghost avatar Feb 14 '17 12:02 ghost

maybe something like public letter to Samsung would be a reasonable first step?

sp-1234 avatar Feb 14 '17 12:02 sp-1234

It is an Oculus requirement and it is something that you do want inside the headset to reduce/eliminate motion blur. Here are a few links that explain low-persistence mode:

https://vrwiki.wikispaces.com/Low+persistence https://forums.oculus.com/vip/discussion/7181/persistence-101-how-low-persistence-reduces-motion-blur

That being said, it really shouldn't be bothersome inside the GearVR headset. It is most noticeable when in developer mode and just holding the phone.

thomasflynn avatar Feb 14 '17 18:02 thomasflynn

When I put the phone in the GearVR and look at anything bright the flickering is so extreme I can't use the device for more than a minute. My wife tried it and had the same problem. So this is something that is a complete showstopper for us. In Cardboard mode (without low persistence) everything works fine.

ghost avatar Feb 14 '17 21:02 ghost

The first thing I did after trying the GearVR for the first time was google the flickering becausebI was sure my device was somehow broken.

ghost avatar Feb 14 '17 21:02 ghost

It may be that you have significantly higher than average sensitivity to the low persistence mode effects. Similarly impacted individuals have suggested that turning down the brightness reduces the effect to manageable levels. If you are developing in Gear VR, it is also suggested that you use darker imagery to help reduce the effect.

robcuts avatar Feb 15 '17 20:02 robcuts

turning down the brightness reduces the effect to manageable levels

Nope, it doesn't reduce flickering, this is not even close to a solution.

sp-1234 avatar Feb 16 '17 09:02 sp-1234

That being said, it really shouldn't be bothersome inside the GearVR headset

Really? In real life, I'm yet to meet at least one human being who doesn't notice this madness. All who looked at it said that this is completely unusable.

sp-1234 avatar Feb 16 '17 09:02 sp-1234

Are you running Android M (6) or N (7) and which model of phone?

thomasflynn avatar Feb 17 '17 02:02 thomasflynn

Samsung Galaxy S7 Android N (7.0)

ghost avatar Feb 17 '17 07:02 ghost

I'm guessing SM-G930F? The letter at the end is important. There is literally a different Android tree for each model :(. One of our engineers has seen something on Android N on a 930F where the screen is dimmed far more than it should. Though, it may just be the version of the engineering (not user) build he has on his device. If it's not just an issue with his device, we'll contact HQ and see if it is a known issue.

If you still see flickering on other devices running Android M, then I don't think there's much I can do to help.

thomasflynn avatar Feb 18 '17 01:02 thomasflynn

It's the 930F

ghost avatar Feb 18 '17 08:02 ghost

@rolandrohde Just out of curiosity, are you adjusting the brightness via the Oculus menu? Long-press back key, settings option. Reducing the brightness from there has no effect whatsoever for you?

liaxim avatar Feb 21 '17 17:02 liaxim

I'll try it next time I dig out the GearVR. I'm pretty confident it won't make a huge difference though. It will probably reduce the issue slightly, since it will be dimmer, but that won't change the frequency of the flicker so the real issue remains. I know from experience that goes back to the era of CRT monitors, that anything below 75Hz is unpleasant to my eyes. Somewhere around 85Hz is stops being a problem altogether. I remember, that 75Hz was the lowest refresh rate I could tolerate for more than a few minutes.

ghost avatar Feb 21 '17 17:02 ghost

@rolandrohde CRTs have lower minimum scan frequency threshold, because the flickering is also softened a bit by the fact that luminophore doesn't instantly go dark. conversely, LED can be switched instantly so the flickering can be made more harsh. LED display backlights can inflict major suffering even at 240Hz (which is common for crappy PWM-driven backlights. Good ones either use much higher frequency for PWM, or avoid PWM altogether) And here, the frequency is about 60Hz and the switching is instant, so this is completely insane.

sp-1234 avatar Feb 22 '17 09:02 sp-1234

Well, the Galaxy S7 uses OLED, so there is at least no chance of backlight flicker...

ghost avatar Feb 22 '17 09:02 ghost

OLED can switch instantly, too. And in practice OLED displays are almost always flickering just as bad (don't know why do they do this, though)

sp-1234 avatar Feb 22 '17 10:02 sp-1234

The flickering kills my eyes too.

Back in time I choosed a flat screen with LCD over Plasma because of that.

karim789 avatar Aug 27 '17 17:08 karim789

I know there hasn't been much discussion for over a year on this thread now, but I would also like to ask for a way to disable low persistence mode for my specific research application. Thanks!

constructor-s avatar Jan 17 '19 18:01 constructor-s