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I have a nook color, I was wondering if anyone notices a very slight screen flicker like a low refresh rate? Most people would not notice. It doesn't bother me much but I wanted to see if its normal. I notice it most on a dark grey background at 50 percent or lower brightness.
Sent from my HTC Vision using Tapatalk
Yes! finally someone that notices it! I have been posting this on other forums. I notice it too on dark backgrounds with about 20-40% brightness, Not sure if it can ever be fixed with an update, but it is sometimes annoying, although not highly noticeable.
I have worked with computer enough that I can tell the refresh rate of a crt just by looking at it. If its normal I am not to worried I justed wanted to know if it was defective because ill switch it out before I root it.
Sent from my HTC Vision using Tapatalk
I get the same thing, very noticeable when you are changing the brightness setting. I use the lowest brightness to read an eBook, and I can really notice the flicker when I lower the brightness, but I can notice it when I get back to the reading screen.
I see it on darker images...its so subtle I ignore it.
Sent from my NOOKcolor using Tapatalk
I still have mine stock... but I see it as well.
Anyone that has loaded any other apps notice it in those apps? i.e. does it flicker noticably in Angry Birds? or other apps?
thanks.
J
I wonder if it being an IPS screen has anything to do with it. It doesnt bother me to much but causes more eye strain than reading from my htc g2. You would think they would make sure an ebook reader doesnt flicker. oh well i can deal with it.
sdelcegno said:
I wonder if it being an IPS screen has anything to do with it. It doesnt bother me to much but causes more eye strain than reading from my htc g2. You would think they would make sure an ebook reader doesnt flicker. oh well i can deal with it.
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It's not the screen, per se, but the LED's that are lighting it up. From what I've read, LED's can't vary output with respect to voltage (they're not dimmable), so you have to pulse them very fast to change the output. I assume that the lower the "level" the more the LED is off vs. on, hence the flicker.
Dang I can't post links yet...
Go to Wikipedia, and look for :
/wiki/Backlight#Flicker_due_to_backlight_dimming
I'm pretty sensitive to this, but haven't noticed it on my iPad, but apparently it does it as well. I was wondering why the stock lowest brightness levels were so friggin' bright - probably at the threshold of flicker. You can dim more in a browser or ebook app, which is where I see reports of flicker.
Go to Discussions dot apple dot com
/thread.jspa?threadID=2398784
Another reason why I like my old CCFL IPS 12" ThinkPad X32!
-Dan
While you can dim an LED by limiting the current (either via inline resistors or with constant current drivers), you can only do so to a degree. Below a certain current, they will simply not light even though the current goes through the LED. On high performance LED's this is still at a pretty bright level. So instead you use PWM (Pulse Width Modulation) and vary the duty cycle to brighten and dim the LED. As the PWM is at a fixed frequency, with more or less of the cycle being lit or unlit, once the unlit portion becomes substantially longer than the Lit part, you can detect the "Flicker" if you are sensitive to it. This is usually particularly noticeable in the "corner of the eye" if you pan you vision across the area and the device gets paned across you field of vision.
This is done on all the new LED tail lights on cars as well and I hate seeing them at night, when they are almost making me nauseous from the flicker.
Good info thanks. Makes sense but wonder why I don't notice on my led backlit netbook. Guess every screen is different.
yea I really wish there was an update to fix this, but i guess it's just the screen, funny how I have never noticed this on any LCD screen I have ever had from computer to TV
three nook colors - my experience with flicker
My first nookColor had screen flicker, also a mind of its own with phantom taps. Nook #2. Did not have noticeable screen flicker but did have a handful of stuck pixels. Took it back and picked up #3. No stuck pixels, but I've got screen flicker on dark colors. Find it strange that nook #2 didn't have te problem with the flicker. I don't like the flicker at all but think it may be timento live with it.
flicker
Has any one returned a flikering nook color and gotten a better one in return?
Hello, I am having a similar problem with angry birds. My screen sometimes will flash different colors and today the screen stayed completely red for 2 or 3 seconds while playing the game. But other than that I love the rooted nook color. Maybe the graphics chip is not powerful enough for this game.
Firmware update
What you described with angry birds is not the problem I am having. Mine is screen flicker. My eye can basically detect the refresh rate with low brightness or in darker colors.
Tried to change it out. Would say that Best Buy is much easier to exchange things at than Barnes & Noble. Eventually they switched mine out and the new one had a dead pixel. They then let me open two more in store in the store all had dead pixels, so did their display model. All presented in the lower right hand corner of the screen. Would be covered up by the black menu bar normally, but visible when the black menu bar goes away.
Anyway I kept my flickering nook, and talked to someone at Barnes and Noble tech support on the phone. He told me the dead pixels were new to him, but they knew about screen flicker issues. He said they would be releasing a firmware update to address this and other problems very soon.
Just wanted to note that none of these nook colors were rooted.
Yes, same here, I have that on my Witstech A81 (resistive screen) too, more noticeable when the battery level drops. Never noticed this problem on my iPhones or iPad though...can't be Android related can it?
glacon said:
What you described with angry birds is not the problem I am having. Mine is screen flicker. My eye can basically detect the refresh rate with low brightness or in darker colors.
Tried to change it out. Would say that Best Buy is much easier to exchange things at than Barnes & Noble. Eventually they switched mine out and the new one had a dead pixel. They then let me open two more in store in the store all had dead pixels, so did their display model. All presented in the lower right hand corner of the screen. Would be covered up by the black menu bar normally, but visible when the black menu bar goes away.
Anyway I kept my flickering nook, and talked to someone at Barnes and Noble tech support on the phone. He told me the dead pixels were new to him, but they knew about screen flicker issues. He said they would be releasing a firmware update to address this and other problems very soon.
Just wanted to note that none of these nook colors were rooted.
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Thanks. I can see the flicker too on gray screens. I have no other issues though (minus a tiny, tiny bit of give on the bottom bezel). I'll wait and hope it gets fixed in an update. I don't have a lot of time to keep exchanging a good unit.
If it is a known issue and a firmware fix is planed, then I am content with my rooted nook. Thanks for this thread.
I took mine back to B&N today to see if replacing it would fix it. Both store displays didn't have any flicker.
They opened two different nooks and they did the same flickering thing.
So I called Nook technical support. He put me on hold for about 5 minutes. He said he checked about 5 nooks and they all flickered. But he hadn't noticed it before.
So, he will put a ticket into the development team to have it looked at.
So, another confirmation that Nook tech support is aware and looking into it.
My first Nook did not display this behavior. I returned it due to creaking issues, and the replacement did display screen flicker.
I'm hoping it's a firmware issue and not a hardware one!
Currently not a big deal though...
I played with my NC nearly one week and I like it. But I want to know dose anyone notice the screen of NC is flickering. If you couldn't understand what I mean, please refer to below video,
http://www.youtube.com/watch?v=iDnBSWF44rM
it is not so obvious in real world as in video, but it is noticeable and uncomfortable. I have ipad with IPS LCD but never find this kind of issue. It like some kind of low fresh rate issue in early PC screen, so I want to know whether it is possible to fix it via adjust screen refresh rate in OS level.
Your comments are welcome!
Mine does that but only on the gray background, otherwise I don't see any flickering.
I exchanged my first NC because of this issue. The salespeople thought I was nuts until I demonstrated it for them. My new one still does it but MUCH more faintly and not all the time. I do believe that Barnes & Noble is aware of it (or at least that's something I read in another thread here somewhere..).
It seems to only happen at middling levels of brightness. My first NC exhibited the issue under very specific settings and times, the brightness had to be set between 20%-40% and I had to be displaying a solid area of mid-range colors. I saw it all the time when the screen would dim to display a menu.
From personal experience, you MIGHT be able to get a unit that's better if you exchange. It does seem to be a very common issue, though. Rumor has it that it might be fixable through a firmware update.. we shall see.
I had a pocket pc with this problem many moons ago...The fix was to adjust a trim pot on the display...
No idea if anything like that would apply here, but just wanted to mention it.
I do have similar problem, could any people advise on how to check the refresh rate and increase it?
Many thanks.
Are you planning on rooting or installing another ROM on your Nook? The overclock kernels fix this issue.
from what I see there in the video, if that is what you are seeing...not refresh rate. Rather it looks like a cycling in the backligt control. Almost looks like the PWM duty cycle is out of wack...would explain why it happens at mid range of the brightness.
My first nook color had this problem, I solved it by leaving the brightness up all the time which seemed to prevent it. I got it replaced for other display issues, and my new one doesn't flicker at any brightness, so yeah it sounds like a defect.
Not a defect. It's a problem with stupid coding in the backlight driver.
They set the PWM (pulse width modulation) rate too low, at 40Hz if I remember right. It's easy to fix by setting it up to 60Hz in the driver, which I did in my old Quickie kernel. Totally gets rid of the flicker, and I've seen no side-effects, nor have any been reported to me.
I don't have the time to keep up with the kernel anymore, and for some reason no other kernel dev has pulled my driver fix into theirs. You might talk to Dalingrin or one of the other devs if you really want it, and put them in contact with me at [email protected] and I can help them get it integrated into their kernel.
Can you link to the github commit?
Tx
Sent from my HTC Vision using XDA App
Hmmmm.... my Nook definitely had the flicker issue on most gray colors, especially at dimmer brightness settings. I'm not using your kernel, but I am using Dalingrin's. I haven't seen flicker in months. Could this issue be limited to the stock ROM only?
911jason said:
Hmmmm.... my Nook definitely had the flicker issue on most gray colors, especially at dimmer brightness settings. I'm not using your kernel, but I am using Dalingrin's. I haven't seen flicker in months. Could this issue be limited to the stock ROM only?
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It appears that way from my experience. I was running the dual boot package with stock and CM7 nightly.
The stock rom flickered very noticeably on greyish type backgrounds. Using CM7 and now Phiremod, the flickering has totally gone away.
Actually the fix is already in init.encore.rc:
Code:
write /sys/devices/omapdss/display0/timings 68000,1024/70/200/40,600/10/11/10
That said, it's going into the driver too.
I love the phone but I've noticed that while navigating the phone the brightness flickers or pulsates somewhat. It's also noticeable when watching video. Also I've noticed when I swipe from blinkfeed to my main home screen I can tell the screen gets slightly dimmer.
It doesn't seem as pronounced when I disable auto-brightness but it still seems to happen.
Just wondering if anyone else has noticed this.
I also have but I can't consistently recreate the issue so I havent tried to get a replacement yet
Sent from my HTCONE using xda app-developers app
After messing around with the phone more it seems to me like the brightness adjusts depending on what is on the screen, like if I launch an app the brightness might change but once it does it seems consistent until I do something else. I don't know if it's trying to adjust dynamically based on what's being displayed or what.
Not really sure if it bothers me enough to do anything about it.
I had like a wave go through my screen while using the cam odd anyone notice the lines in the screen when its off ?
Sent from my HTC6435LVW using xda premium
I haven't noticed that.
I actually went to Best Buy over the weekend and exchanged my phone to see if a different one would be better about the brightness adjusting constantly. My new phone seems about the same but I think I'm kind of getting used to it, also I just don't feel bad knowing that it seems to be widespread.
Hey guys I have another strange problem on my n6. It seems that when I am in an app landscape half of the screen (bottom) turns black and sometimes flashes what it's supposed to be and will go back again. Scrolling makes it worse but I can tap through the black portion and highlight text and it will temporarily go away. It almost looks that the keyboard is trying to pop up but I've switched my keyboard and I can reproduce it in multiple apps
Chromium + Franco newest
Bump
A 2 hour bump is not needed. There are threads about your issue and I am sure someone will reply. Just give them time.
Sent from my Nexus 6
You have changed your DPI, possibly to 493. Try changing it to 496 instead and you'll see that the problem disappears...
If you're not using 493 you're using another DPI that the N6 doesn't like. Try changing to something else, preferably a multiple of 8, apparently.
Did this work for you? On Chroma and experienced the same today.
The half screen issue is a known issue with the GPU. Some of the devices that were manufactured up till January have had defective GPU's. Call moto and you may qualify for a RMA.
Hi everyone,
Got my Pixel 4 XL on the 23rd and been playing around with it since then. I am now settling into a rhythm and noticed a very concerning glitch with the display when the phone is in dark mode. Basically, when the phone is in dark mode I noticed that typing in Gboard or tapping anywhere on screen in apps that are not pure black (such as Messages, Phone, etc.) will shift the screen colour from blueish-black to greenish-black. This happens every time, even after rebooting the device. There is no visible colour shifting in apps that use pure-black such as Settings (however, parts of Settings like the search bar that are the "gray" dark colour also shift). Once I noticed this happening now I cannot stop noticing it everywhere. I am looking to find out from you whether you are seeing the same thing or whether this may be a device problem. Note that the same issue shows up in dark apps even if dark mode is not enabled. It also has nothing to do with Ambient EQ, Automatic Brightness, or anything else of similar nature. Occasionally the problem stops, but if I pull up Gboard and start typing (say to search in the Recent section of the phone app) the problem immediately comes back.
I am looking for serious feedback here from those willing to look closely. This does seem like a software glitch to me, rather than hardware, especially since I am not seeing this behaviour with any other colours and so far it definitely has something to do with physical interaction with the screen when tapping on it. As I said, it also seems to be universally triggered by Gboard when in apps running in dark mode.
I appreciate any feedback you can provide.
Edit: Looks like what I'm observing is related to the switching colour profiles when the display is going back and forth between 60Hz and 90Hz. Turning off the smooth display function or forcing the display into permanent 90Hz mode appears to stop the problem from happening. Google really messed this one up. I hope their 90Hz fix they promised clears up this issue. Very annoyed ?
Thanks,
Dejan
Btw, since you are using forced 90hz display make sure to have always on display on. If you don't your greys will be purple and lower brightness as well as lots of black smear/crush. I don't know how turning on always on display solved that issue (someone posted this fix in another thread). So it indeed doesn't seem to be hardware but software related and hopefully they will tune this over time.
zetsumeikuro said:
Btw, since you are using forced 90hz display make sure to have always on display on. If you don't your greys will be purple and lower brightness as well as lots of black smear/crush. I don't know how turning on always on display solved that issue (someone posted this fix in another thread). So it indeed doesn't seem to be hardware but software related and hopefully they will tune this over time.
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Yeah, I saw that thread. Some funky stuff going on with display calibration and 90Hz. Since I know that the HW is not defective and the SW is the source of the issue I am less bothered now (I cannot stand exchanging HW). I haven't specifically observed that effect on my phone and while I did try forcing 90Hz, I actually went back to the stock setting since I noticed that forced 90Hz further sucked down the battery that already is not particularly stellar despite this being the XL version. I presume Google will refine the 90Hz calibration and function over the next few months. I will say though that I am a bit confused why they need to have different calibration at different refresh rates. I calibrate all of my desktop monitors and despite the fact that I have a 100Hz monitor I never have to change calibration with refresh rate. Maybe an OLED thing :shrug:
dhorgas said:
Hi everyone,
Got my Pixel 4 XL on the 23rd and been playing around with it since then. I am now settling into a rhythm and noticed a very concerning glitch with the display when the phone is in dark mode. Basically, when the phone is in dark mode I noticed that typing in Gboard or tapping anywhere on screen in apps that are not pure black (such as Messages, Phone, etc.) will shift the screen colour from blueish-black to greenish-black. This happens every time, even after rebooting the device. There is no visible colour shifting in apps that use pure-black such as Settings (however, parts of Settings like the search bar that are the "gray" dark colour also shift). Once I noticed this happening now I cannot stop noticing it everywhere. I am looking to find out from you whether you are seeing the same thing or whether this may be a device problem. Note that the same issue shows up in dark apps even if dark mode is not enabled. It also has nothing to do with Ambient EQ, Automatic Brightness, or anything else of similar nature. Occasionally the problem stops, but if I pull up Gboard and start typing (say to search in the Recent section of the phone app) the problem immediately comes back.
I am looking for serious feedback here from those willing to look closely. This does seem like a software glitch to me, rather than hardware, especially since I am not seeing this behaviour with any other colours and so far it definitely has something to do with physical interaction with the screen when tapping on it. As I said, it also seems to be universally triggered by Gboard when in apps running in dark mode.
I appreciate any feedback you can provide.
Edit: Looks like what I'm observing is related to the switching colour profiles when the display is going back and forth between 60Hz and 90Hz. Turning off the smooth display function or forcing the display into permanent 90Hz mode appears to stop the problem from happening. Google really messed this one up. I hope their 90Hz fix they promised clears up this issue. Very annoyed ?
Thanks,
Dejan
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I just noticed this on my pixel 4 xl tonight. But It only happens when the proximity sensor is triggered. Ex: like after making a phone call except it made everything on the screen seem over saturated on the screen and well as the same color shift you had stated. It seems to go away once I lock the device and unlock it again. It did it with smooth display on and off as well as force 90hz on and off.
There are a couple threads discussing this. Here's one of them:
https://forum.xda-developers.com/pixel-4-xl/how-to/smooth-display-colour-issues-t4000087
And another:
https://forum.xda-developers.com/showthread.php?t=3998907
Sent from my Pixel 4 XL using Tapatalk