Develop Bugs

[Q] Why is the refresh rate on the Note 2 58hz?

Hello folks,
I have had my Note 2 for a couple of days now and almost immediately noticed something strange. There is a VERY subtle flickering of the white and light grey areas of the screen. A very high frequency flicker, almost like I can see the refresh rate of the screen. My initial suspicion was that the refresh rate was lower than 60hz. So, I downloaded the app called Android System Info, and sure enough, under display, it was being reported that the refresh rate of the screen is 58hz. I got another friend with a Note 2 to confirm the same thing. My GS3 reports 60hz, and so does my friends HTC One S. So my question is, why is the refresh rate on the Note 2 not 60hz? Is this an intrinsic hardware limitation? Or can this be changed with software? My eyes can definitely notice the 2 less frames per second, I was using a GS3 since June, and switching to the Note, I immediately noticed the refresh rate was lower. Why? This is very strange to me. There are many videos on YouTube with the Note 2 and GS3 on the screen at the same time, and sometimes there is banding interference on one phone and not the other, meaning obviously the phones are running different refresh rates. Now I know the Note 2 refresh rate is lower, why? And is there anyway to change it with software?
Thanks much!

first, i think u should get yr note2 to warranty,
second, u sure yr eyes can differentiate 58hz and 60hz......?

emprize said:
first, i think u should get yr note2 to warranty,
second, u sure yr eyes can differentiate 58hz and 60hz......?
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Click to collapse
It is EXTREMELY subtle, almost a non issue, so I doubt warranty will even say anything is wrong. I can notice it on all the demo models i've seen, so I doubt it has anything to do with my phone.
I have confirmed on 3 different Note 2s, the reported refresh rate in the app 'Android System Info' is 58hz. While all other phones I have used report 60hz.
I just find this so strange that maybe someone has a great explanation as to why this is the case. And maybe someone can dig deeper than I can and figure out if this is in the OS or an intrinsically hardware thing. I wish I had the email of a Samsung engineer who worked on the design of this phone, would love their take on why this is the case. 58hz is just such a strange refresh rate.

Goontron said:
It is EXTREMELY subtle, almost a non issue, so I doubt warranty will even say anything is wrong. I can notice it on all the demo models i've seen, so I doubt it has anything to do with my phone.
I have confirmed on 3 different Note 2s, the reported refresh rate in the app 'Android System Info' is 58hz. While all other phones I have used report 60hz.
I just find this so strange that maybe someone has a great explanation as to why this is the case. And maybe someone can dig deeper than I can and figure out if this is in the OS or an intrinsically hardware thing. I wish I had the email of a Samsung engineer who worked on the design of this phone, would love their take on why this is the case. 58hz is just such a strange refresh rate.
Click to expand...
Click to collapse
you are the man, mate, my eyes cant even differentiate 50 and 60 Hz, for all my note2 experience, i cant see any unusual on the screen.
But for the 58hz issue, i think its not quite a strange thing for me, it reminds me when i was using CRT monitor(or early lcd?), it always can set the refresh rate to 58hz or 60hz, but it might like u say a hardware or driver problem, hope u can contact with samsung engineer and tell us the answer

I suppose the app might be reading the values of somewhere not actually measuring it or something ! Correct me if am wrong .

this is interesting. i also notice a subtle flicker of the screen. it's annoying in some lighting. i don't notice it on other phones.. it's definitely seems like the refresh rate is a bit slower than it should be.

The refresh rate is correlated with the resolution and the main base clock which feeds the display controller, in this case 1280 * 720 * 58Hz = ~54Mhz plus some margins for which are too long to describe, which gives them a target frequency of about 54MHz for a 16 divider of the 880MHz base clock. That's the main reason of the 58 vs 60 Hz difference.
But the reason you're seeing flickering might be completely unrelated to that and caused by some odd much lower timings in the display settings. Maybe a developer with the device could test it out by changing them.

AndreiLux said:
The refresh rate is correlated with the resolution and the main base clock which feeds the display controller, in this case 1280 * 720 * 58Hz = ~54Mhz plus some margins for which are too long to describe, which gives them a target frequency of about 54MHz for a 16 divider of the 880MHz base clock. That's the main reason of the 58 vs 60 Hz difference.
But the reason you're seeing flickering might be completely unrelated to that and caused by some odd much lower timings in the display settings. Maybe a developer with the device could test it out by changing them.
Click to expand...
Click to collapse
Thanks for that information, it's great technical info I've been looking for. So it's basically a ratio/multiplier of some clock speed in the hardware. But now my question is, why would the Note 2 be any different than a GS3? I would think they have relatively the same hardware, and resolution on both screens is the same, so why would the refresh rates differ? Just seems to me that 58hz is not an ideal refresh rate. I mean, the main reason there is a trend towards 120hz TVs these days is because both movies (24 fps) and TV (30 fps) are evenly divisible into 120. Whereas with a 60hz TV, there is a remainder on 24, so movies do not interpolate as smoothly. With 58hz, no recorded content I can think of divides evenly into it, always making interpolation less smooth. Again, in my mind, 58hz is just silly, why not just give me the extra 2hz!! Doesn't make sense to me.
Final question. Would there be any way with software to change the refresh rate? Or is this set in stone at the hardware level?

I have an issue with this as well - I'm getting either fairly heavy frame skipping in any 8 or 16 bit emulator with frame skipping set to auto, or sound skipping with frame skipping turned off. I suspect this is because of the odd refresh rate with the app expecting 60hz and only running at 58 in reality, causing either the video or audio to run out of sync and needing to skip the two frames here and there to catch up. If the emulators could slow down the audio speed to match the slower video speed, it wouldn't be an issue.... but this shouldn't be the problem of the emu authors.
This happens with no other applications installed on a brand new phone. I've also installed clean rom and perseus kernel, no change. Power settings are all off, nothing is hitting my CPU to cause the frameskipping and it's very consistent, which leans towards the refresh rate causing the issues. Anyone know anything more about this? What a pain...

I am a traffic cop and I can definitely tell the difference between a car going 58mph and one going 60mph.
Sent from my GT-N7100

@rbiter said:
I am a traffic cop and I can definitely tell the difference between a car going 58mph and one going 60mph.
Sent from my GT-N7100
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Click to collapse
I'm a noob and I don't know what "stuttering" is
But seriously, it's not like a mobile device should be able to emulate another system anyway, am i rite? Just use it for phone calls and internet browsing...

i think the reason why the refresh rate between gs3 and note2 is different due to both are using different lcd even though some of the hardware is the same.
even though the diff is small but it still incur some major hiccup where the frame skip especially with project butter where they keep the ui at 60fps.
maybe we can email to samsung engineer and they can take a look at it.

Note 2 flickering display

What about this?
I make this video in the shop.
http://youtu.be/UoLb-9Sli_U
Why display flicker like a 60 Hz old monitor?
Samsung EPIC FAIL.

Exand said:
What about this?
I make this video in the shop.
http://youtu.be/UoLb-9Sli_U
Why display flicker like a 60 Hz old monitor?
Samsung EPIC FAIL.
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Click to collapse
Lmfao sorry what flicker. This ain't cm10.!

Exand said:
What about this?
I make this video in the shop.
http://youtu.be/UoLb-9Sli_U
Why display flicker like a 60 Hz old monitor?
Samsung EPIC FAIL.
Click to expand...
Click to collapse
Omg. Before posting such ridiculous nonsense why dont you go and look at a note 2 and avoid ending up looking like fool?
OP EPIC FAIL!
ADMIN please close this.
Sent from the Mighty Galaxy Note 2!

Neeeerrdddddd

Kcid
Sent from my SAMSUNG-SGH-I317 using xda premium

http://electronics.howstuffworks.com/question336.htm
The flicker is caused by two things:
A difference in the scanning frequency between the TV and the camera
A difference in the way the phosphor dots are perceived between the human eye and the camera's image sensor
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Click to collapse
It says TV and camera, but it's the same thing for your case.

These screens do flicker... like it or not.
Flicker while recording a screen, possible reasons:
The flicker is caused by two things:
A difference in the scanning frequency between the TV and the camera
A difference in the way the phosphor dots are perceived between the human eye and the camera's image sensor
Click to expand...
Click to collapse
I agree with that.
Still, these displays DO flicker.
To be specific: Galaxy S3 and Note 2.
There is a considerable amount of flickering on these displays, comparable with old CRT monitors switched to 60 Hz.
They glimmer like neon tubes. When you swing them fast, they don't leave continuous traces, but discrete, sliced traces.
Try it yourself. Denying it won't change it.
If you don't see it with your own eyes, then your eyes might be just a bit "lazier", or you might want to check them.
Whatever you do or don't do, try not to humiliate people who do see this flickering.
And yes, to the author of this thread: if you can, shoot Note 1 and Note 2 side by side, so you can eliminate these differences in frequencies from the quote above.
Wait, what frequencies? My Note 1 does not have a frequency... the pixels emit light continuously (only their value is changed every 60th of a second - if it's changed at all, not on still images - but they do not turn of and back on 60 times per second... unlike Note 2's).

I needed to run my old crts at 75 at least to not go crazy with flicker so you cant call my eyes lazy
Sent from the Mighty Note 2!

same problem
I too face the same flickering problem...do I get it replaced ?

[Q] Does the Galaxy Note 8.0 have PWM?

It would be great if somebody can test it, thanks in advance.
How to test:
put a camera in front of the screen and play around with the shutter speed and the brightiness of the screen. When lines appears on the screen, its not good => pwm, without lines => good :good:
edit: i had links for pwm explanation, but not enough posts, sorry..

The question is about pulse width modulation, which I'm reading occurs when both of the following are true:
- you are using an LED light source with variable brightness
- you are using a camera with a rolling shutter
http://provideocoalition.com/aadams/story/pulse_width_modulation_is_not_your_friend/
The camera on the note 8 does not have an LED flash, so I think the poster either now knows that it won't be an issue, or is curious as to whether display brightness on the screen is controlled by pulse width modulation or a different technique.
In the latter case, I don't know, and since this is stuff that can't be seen by the eye nor in the viewfinder, but mostly in photo editing suites per the article I link to, I'm not sure why it's an issue here.

Hi roustabout
I think we dont speak about the same topic.
What I mean is the flickering of the display. A good example is found on youtube: Nexus 7: no PWM on LCD
A lot of LCD use this technology to dim, but its not proper dimming, just switch on / switch off the the lcd very quickly.
Some people have problem with this flickering but dont know that theres a problem, so for example dry eyes, getting tired very fast when working on the computer..
I think more the 95% of the usual monitors use this technique.
I hope this helps.

no, we're talking about the same thing:
'curious as to whether display brightness on the screen is controlled by pulse width modulation or a different technique.'
The article I found thinks it's not visible; what you've read or experienced suggests it's problematic.
What I can say is the first-gen ipad was very hard on my eyes; the note 8 is not like that, but not as good as e-ink. Much more fun than e-ink, though!

MTCB Joying Display flickering and "burned in" picture

Hey there,
I have some issues with the MTCB. Someone had these before?
First problem which is already quite annoying is that pictures are kind of burned in and still show shadows on the other screen
Second problem which is even more bad is that the display flickers. This is more or less obvious in different scenes.
When looking closely it seems like there is a grid (coming and going in the same frequence like the music is playing?). The attached video shows it.
Especially with white background the flickering gets very bad.
Don't know if this could be related to the Malaysk Firmware I use. Or is is it a hardware issue?
Also contacted the support. Let's see what they say...

messiah said:
Hey there,
I have some issues with the MTCB. Someone had these before?
First problem which is already quite annoying is that pictures are kind of burned in and still show shadows on the other screen
Second problem which is even more bad is that the display flickers. This is more or less obvious in different scenes.
When looking closely it seems like there is a grid (coming and going in the same frequence like the music is playing?). The attached video shows it.
Especially with white background the flickering gets very bad.
Don't know if this could be related to the Malaysk Firmware I use. Or is is it a hardware issue?
Also contacted the support. Let's see what they say...
Click to expand...
Click to collapse
Sounds like a screen issue to me, have you checked the ribbon connector hasnt come slightly undone ?

Hi, thanks for answering.
Attached is the video I spoke about. I missed to upload it.
You mean to open the device and check the ribbon connector inside, right?
Regards
edit: the video

messiah said:
Hey there,
I have some issues with the MTCB. Someone had these before?
First problem which is already quite annoying is that pictures are kind of burned in and still show shadows on the other screen
Second problem which is even more bad is that the display flickers. This is more or less obvious in different scenes.
When looking closely it seems like there is a grid (coming and going in the same frequence like the music is playing?). The attached video shows it.
Especially with white background the flickering gets very bad.
Don't know if this could be related to the Malaysk Firmware I use. Or is is it a hardware issue?
Also contacted the support. Let's see what they say...
Click to expand...
Click to collapse
This is commom in these units.
It's worst when it's hot.
I kinda fixed mine opening it and adjusting some kind of screw near the screen. You turn it and screen gets darker, you need to find a point between too dark and flickering. But when I park my car at the sun, and it gets hot inside, screen get bright again, so flickering and persistent images.

And here is a video about it.

pczao said:
This is commom in these units.
It's worst when it's hot.
I kinda fixed mine opening it and adjusting some kind of screw near the screen. You turn it and screen gets darker, you need to find a point between too dark and flickering. But when I park my car at the sun, and it gets hot inside, screen get bright again, so flickering and persistent images.
Click to expand...
Click to collapse
Personally I wouldnt say "common" - I ve only hear about 3 people mention it in the last 3 years.

typos1 said:
Personally I wouldnt say "common" - I ve only hear about 3 people mention it in the last 3 years.
Click to expand...
Click to collapse
It's commom. That's why Joying even put a video online to show how to fix it.
I believe that when they produce the unit, it's now well tuned up, or it's cold in the factory and they don't realize, so when someone who lives in a hot weather area install it, the problem appears.
It's a bad hardware design, they use analog potentiometer, they should use some digital and automatic one to regulate screen frequency.

pczao said:
It's commom. That's why Joying even put a video online to show how to fix it.
I believe that when they produce the unit, it's now well tuned up, or it's cold in the factory and they don't realize, so when someone who lives in a hot weather area install it, the problem appears.
It's a bad hardware design, they use analog potentiometer, they should use some digital and automatic one to regulate screen frequency.
Click to expand...
Click to collapse
Well, Like I said, I ve not heard much about it in the 3 years I ve been following the threads on here, but I do remember Joyous having problems with their screens and 5.1.1 - they couldnt get 5.1.1 to work on their 4.4.4 RK3188 units unless the screen was changed !! Sounds like its more a problem with Joyous units.

I agree there's not many complaints about this problem here, that's why I believe that may be some "quality check" sloppiness. It's very simple to solve anyway.
But all units seems to use analog potentiometer, so, bad design. There's nothing to do with Joying only and the fact they changed screen to update to 5.1.1.
And most users in this forum don't live in hot weather areas. In my case, Brazil, is hot must time of the year, above 34 C degrees (93 F), in the shade.

pczao said:
I agree there's not many complaints about this problem here, that's why I believe that may be some "quality check" sloppiness. It's very simple to solve anyway.
But all units seems to use analog potentiometer, so, bad design. There's nothing to do with Joying only and the fact they changed screen to update to 5.1.1.
And most users in this forum don't live in hot weather areas. In my case, Brazil, is hot must time of the year, above 34 C degrees (93 F), in the shade.
Click to expand...
Click to collapse
Thanks for reminding me that its only 4 C degrees here in the UK

typos1 said:
Thanks for reminding me that its only 4 C degrees here in the UK
Click to expand...
Click to collapse
Don't make me jealous!!
UK weather is great. I've been there once, liked very much.
Some friends are going to travel there later this month. I'm unable to go because my daughter is too young.

pczao said:
Don't make me jealous!!
UK weather is great. I've been there once, liked very much.
Some friends are going to travel there later this month. I'm unable to go because my daughter is too young.
Click to expand...
Click to collapse
Youre envious of 4 deg C ?! I get 34 deg C is a bit hot, but 4 is a bit cold !
Half way between 4 and 34 @ 19 deg C would be perfect

typos1 said:
Youre envious of 4 deg C ?! I get 34 deg C is a bit hot, but 4 is a bit cold !
Half way between 4 and 34 @ 19 deg C would be perfect
Click to expand...
Click to collapse
Agreed!

pczao said:
Agreed!
Click to expand...
Click to collapse
Lol, meet you in St.Helena, thats about half way init?

typos1 said:
Lol, meet you in St.Helena, thats about half way init?
Click to expand...
Click to collapse
I looked at the map and St. Helena is a little to the south, a direct flight seems a better option.
But feel welcome if you want to come to Brazil someday.
It's a bit messy but it's a good country. I'm not going to take you to meet any favela, by the way. Don't know why tourists are so eager to go in one, it's very dangerous, and I don't think they represent Brazil that much, so many different beatiful places to go.

pczao said:
I looked at the map and St. Helena is a little to the south, a direct flight seems a better option.
But feel welcome if you want to come to Brazil someday.
It's a bit messy but it's a good country. I'm not going to take you to meet any favela, by the way. Don't know why tourists are so eager to go in one, it's very dangerous, and I don't think they represent Brazil that much, so many different beatiful places to go.
Click to expand...
Click to collapse
dont worry, slums were not the first thing on my mind when thinking about Brazil

pczao said:
And here is a video about it.
Click to expand...
Click to collapse
Hey there, thanks but the video is not working.
I did not open the unit yet to check if the screw will improve. But I will test soon when I find some time.
By the way it's around 0°C here. So not very warm
Attached is another video. The flickering of the right white picture is actually visible. It's not a flickering of the camera.

messiah said:
Hey there, thanks but the video is not working.
I did not open the unit yet to check if the screw will improve. But I will test soon when I find some time.
By the way it's around 0°C here. So not very warm
Attached is another video. The flickering of the right white picture is actually visible. It's not a flickering of the camera.
Click to expand...
Click to collapse
Here's the link of the video: https://m.youtube.com/watch?v=GsRriCgZzd4
Just open the unit and fix it, very easy.

Took some time until I tried the fix. But the screw fixed it.
Carjoy recommended a power filter, but since the screw fixed it i prefer this...
The screen is now slightly darker. But I like the crisp image and better saturation of the colors (and of course no flicker).
Thanks!

messiah said:
Took some time until I tried the fix. But the screw fixed it.
Carjoy recommended a power filter, but since the screw fixed it i prefer this...
The screen is now slightly darker. But I like the crisp image and better saturation of the colors (and of course no flicker).
Thanks!
Click to expand...
Click to collapse
Does the unit have to be powered on when tighten the screw?
Sent from my Pixel 2 using Tapatalk

General F3: My observations so far

Hello everyone,
I got my device some time ago and wanted to highlight the things that rarely ever get mentioned by your average youtuber.
-) Yes, vibration motor noise is there.
But it feels really intentional, not like it is broken.
For me personally I don't mind it really, just wanted to share it since this is dicussed in this forum.
I don't have the "crackling" that has been mentioned, it feels more like when you set the alarm on an iPhone and rotate the hours/minutes wheel - satisfying.
-) Screen PWM'ing
The display is great, gets decently bright especially when viewing HDR content on YT.
Also the 120Hz is definitely a game changer, you can trust me on that.
What I however noticed coming from my F1 is the PWM.
Feels like they do 240-280Hz PWMing the brightness.
I feel like it is causing me headaches and sore eyes, but might just be the exhaustion after coming home from office work on Thursday's
Will see how it develops - my F1 has also PWM, but at around 4000Hz (!) which is definitely not noticeable.
Anyone of you have noticed the PWM? I might be an isolated case, even all high-end Samsungs's have 240Hz and no one complains ...
If you know a hack to enable DC dimming just shoot me a PM please
Hope I don't have to send it back because of this, would be really a shame.
-) Green tilt
Yes, I have noticed some green tilt at the upper half of the screen.
Only happens at really low brightnesses and with certain silver/grey'ish colors in dark mode with reading mode on.
But it is really minor, you really have to focus to make out a slight green shift.
That is no issue for me really, but wanted to highlight it because of the ongoing discussin.
Actually that was all.
The rest is great so far.
Extremely fast, premium build, nice AOD, battery is good so far, camera is more than enough for me and the sound quality is excellent.
If you want to me to test/check out something just let me know, as long as it doesn't involve ADB

Motor noise?

djuroue1 said:
Motor noise?
Click to expand...
Click to collapse
The vibration motor for the haptic feedback.

GeForce66 said:
The vibration motor for the haptic feedback.
Click to expand...
Click to collapse
Ah ok.I didnt hear that.

About Dc dimming:
I have read that they had problems with it, so it might not come to the stable version but it can be enabled in the developer version.

darkb7 said:
About Dc dimming:
I have read that they had problems with it, so it might not come to the stable version but it can be enabled in the developer version.
Click to expand...
Click to collapse
Any link you can share with me? Maybe there is a chance I can give it a try.

GeForce66 said:
Any link you can share with me? Maybe there is a chance I can give it a try.
Click to expand...
Click to collapse
It was stated about the K40 on Weibo by a Xiaomi official, but since it is the same phone as Poco F3 I guess the situation is no different.
Here is a link: https://en.xiaomitoday.it/redmi-k40-poco-f3-dc-dimming.html

Yeah so I have packed it up again and will send it back to Amazon.
Unfortunately the PWM does not go along with my eyes/brain.
But other than that, great device - can definitely recommend, just make sure you are not sensitive to PWM.

When does PWM kick in according to the brightness settings?

From what I have seen as soon as you are below 100%

PWM?

_j3roen said:
PWM?
Click to expand...
Click to collapse
This should explain very well: https://www.oled-info.com/pulse-width-modulation-pwm-oled-displays

Can you please help me.. I don't know if my eyes are sensitive to pwm or not as I've always used an ips and I don't have the option of returning the phone, I used to get a headache behind my eyes while using my old pc for a long time, so does it relate to it or did you have the same problem?

Well yes, it could be - or you just were in front of the screen too long in general.
For me only my eyes start to burn when i have work in front of the pc all day, but no pain behind the eyes. This only happens with PWM'd OLEDs it seems.
What monitor have you been using with your pc?

GeForce66 said:
Well yes, it could be - or you just were in front of the screen too long in general.
For me only my eyes start to burn when i have work in front of the pc all day, but no pain behind the eyes. This only happens with PWM'd OLEDs it seems.
What monitor have you been using with your pc?
Click to expand...
Click to collapse
samsung monitor b1930n, I used to get the pain after playing for long time. I then switched to a laptop (lenovo z50-70) and the frequency of the pain decreased a lot

I couldn't really find much information. If you have the chance just point a camera at the screen when set to medium/low brightness, if you see the flicker then your screen uses PWM.

To anyone wondering about PWM in the future, notebookcheck measured it at 490Hz. This should be fine for almost anyone.
My current phone Mi 9T has 240 and I did not even know it, so I'm good. Had me scared for a bit with the headaches and whatnot

This is a great phone and I am actually impressed by its display. It's so clear to the point that I enjoyed watching cricket matches on this phone. Great sounds as well, especially for the fact that it's not expensive.

Need assistance !
I'm planning to buy this phone since I'm done with my mi 10T .
Mi 10T having 1 issue which is the only reason i will let it go . The earpiece
has the ultrasonic technology which is annoying and unstable causing a lot of calling issues since there's no a proximity sensor . Even the WhatsApp voice notes having the same issues .
I have looked around for newer phone which i think poco F3 might be the one!
I have tried to look around if xiaomi still using that stupid technology init ! But no luck.
If ur facing proximity sensor issues please confirm since my birthday is coming on sept 18th and I will gify my self a new
Thanks

If you want to change because of the proximity sensor, give the F3 a wide berth. Whether the problem can ever be solved via software is written in the stars - and it is cloudy, very cloudy... I don't think Xiaomi will ever fix this issue.