Author Topic: P10 panel flickering outline  (Read 1449 times)

Offline adster

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #15 on: August 22, 2017, 03:23:57 PM »
Ok, so I got a BBB and Octoscroller and the ghosting issues are not a thing anymore! So there must be some code in the Raspberry Pi FPP that is making the panels ghost like that. I tried this on my P4 panels and some new P10 panels I got from DIY LED Express and it produces the same result, so I know it's not a panel issue.


Here's a video showing the difference between the two:
https://youtu.be/AjgYYqFHDSA
and part 2 showing with the updated dklup BBB image.
https://youtu.be/g-15zNuNIOk


However, now I'm getting some refresh issues with the top and bottom portion of the panel. Notice how the top half of the panel moves just slightly faster then the bottom half? This doesn't happen on the pi and is visible in part 2 of the above video.

Offline adster

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #16 on: August 22, 2017, 03:44:28 PM »
I was able to make some progress with this issue. Since FPP is using an older version of the RGB Matrix library, the settings shown in the documentation that I mentioned earlier are not available.

I was able to find a constant in the code that controls the PWM Nanoseconds for LSB. I manually changed it and rebuilt FPP using the following.

Code: [Select]
cd /opt/fpp/external/rpi-rgb-led-matrix/lib
sudo nano framebuffer.cc

modify the following line "static const long kBaseTimeNanos = 130;" and change 130 to 300
Save the file and exit

sudo make
cd /opt/fpp/src
sudo rm fppd
sudo make

I then restarted FPP and ran some tests.

The ghosting is now gone for the most part. It still seems to show a little when the text is first displayed but goes away completely after a second. So, I don't know if there is something else in the code that needs changed.

Would it be possible to update the library to the latest version and add this as a setting on the matrix page? I would be willing to do this myself even it was only on my local copy, but I am not that familiar with Linux or the FPP code. So, I would probably need a lot of help.


After the
cd /opt/fpp/src
and
sudo rm fppd
I get an error: "rm: cannot remove `fppd': No such file or directory"
Should I remove fppd.*? I see fppd.c .h and .sh.

Offline rmp2917

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #17 on: August 22, 2017, 10:32:09 PM »
The FPP folder may be in a different directory depending an what version you are running. Make sure your FPP folder is under opt.

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #18 on: August 23, 2017, 10:43:02 AM »
I am having the same issue with the random ghosting around text .  I am using a Pi3 with Rons  adapter and just received P10s.  I hope we can get this solved because it makes the matrix ugly.

Offline rmp2917

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #19 on: August 23, 2017, 10:18:31 PM »
After the
cd /opt/fpp/src
and
sudo rm fppd
I get an error: "rm: cannot remove `fppd': No such file or directory"
Should I remove fppd.*? I see fppd.c .h and .sh.

You don't want to delete any other files. I don't think the error is an issue just go ahead and run the sudo make at the end and see if it will build.

I am currently travelling and won't be back home until Sept. 1st. I will try to play with it some more and maybe create a new build if I get it working good.

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #20 on: September 04, 2017, 11:30:06 AM »
Anyone figure out what the problem is.  Is there an update to the code? Any help would be greatly appreciated.

Offline dkuntz

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 13
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #21 on: September 05, 2017, 07:27:24 PM »
I noticed this issue with "ghosting" around text on my p10 matrix tonight. I am powering my pi and matrix with the same power supply. I found the ghosting seemed to go away when I adjusted the voltage down to about 4.7 volts. I was surprised the pi seemed to continue to function at this voltage. I will be trying powering the pi with a separate supply when I get a chance. No idea why this made my ghosting go away.

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #22 on: September 06, 2017, 05:54:52 PM »
I changed my pi to USB power instead of Ron's Adapter and the text is still very jagged.

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #23 on: September 06, 2017, 08:39:03 PM »
Just tried a different Pi3 and a different Ron Matrix Adapter and still no luck. :-\. Anyone have any suggestions? I'll try anything. 

Offline rmp2917

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #24 on: September 09, 2017, 11:53:37 AM »
I have finally had some time to experiment with this some more and have made some progress.

The setting that seems to have the most effect is GPIO-slowdown. Changing it from 1 to 2 seems to completely get rid of the flickering pixels, but there is still some very faint ghosting especially on green and white. Changing the pwm_lsb_nanoseconds parameter from 130 to 300 completely gets rid of the ghosting but will decrease the refresh rate.

I recommend changing the GPIO-slowdown setting and experiment with values for the pwm-lsb-nanoseconds parameter to find a value that best works for your display. Lower values give you a higher refresh rate that reduces pulsing/flickering but will cause more ghosting. Higher values reduce ghosting but will lower the refresh rate and could cause pulsing/flickering. You can also experiment with different brightness values. Reducing the brightness may get rid of the faint ghosting without sacrificing refresh rate.

I am not an FPP expert so I don't know if this is the best method to make these changes or not, but here is what I did to make the changes.

Code: [Select]
Start SSH Shell from the Help menu of FPP
Login using username: fpp and password: falcon

Type the following commands:

cd /opt/fpp/external/rpi-rgb-led-matrix/lib
sudo nano frambuffer.cc

modify the line that says static const long kBaseTimeNanos = 130; and change 130 to 300 (try different values between 130 and 300 to see what works best for your display)
Press ctl-o and hit enter. Press ctl-x

sudo nano Makefile

modify the line that says DEFINES+=-DRGB_SLOWDOWN_GPIO=1 and change 1 to 2
Press ctl-o and hit enter. Press ctl-x

cd ..
sudo make

cd /opt/fpp/src
sudo rm fppd   (dont worry if you get an error indicating file does not exit just continue to next step)
sudo make

close the SSH Shell
click restart FPPD in FPP
you may need to close the browser and reopen or reboot the Pi for the changes to take effect.

I still think it would be good if we could update the matrix library to the latest version and add these options to the LED panel settings.

I will be very busy getting other things ready so I don't if I will have any time to do any more with it before Christmas. But, the above changes at least seem to provide a working solution to the problem.

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #25 on: September 09, 2017, 02:04:00 PM »
I have finally had some time to experiment with this some more and have made some progress.

The setting that seems to have the most effect is GPIO-slowdown. Changing it from 1 to 2 seems to completely get rid of the flickering pixels, but there is still some very faint ghosting especially on green and white. Changing the pwm_lsb_nanoseconds parameter from 130 to 300 completely gets rid of the ghosting but will decrease the refresh rate.

I recommend changing the GPIO-slowdown setting and experiment with values for the pwm-lsb-nanoseconds parameter to find a value that best works for your display. Lower values give you a higher refresh rate that reduces pulsing/flickering but will cause more ghosting. Higher values reduce ghosting but will lower the refresh rate and could cause pulsing/flickering. You can also experiment with different brightness values. Reducing the brightness may get rid of the faint ghosting without sacrificing refresh rate.

I am not an FPP expert so I don't know if this is the best method to make these changes or not, but here is what I did to make the changes.

Code: [Select]
Start SSH Shell from the Help menu of FPP
Login using username: fpp and password: falcon

Type the following commands:

cd /opt/fpp/external/rpi-rgb-led-matrix/lib
sudo nano frambuffer.cc

modify the line that says static const long kBaseTimeNanos = 130; and change 130 to 300 (try different values between 130 and 300 to see what works best for your display)
Press ctl-o and hit enter. Press ctl-x

sudo nano Makefile

modify the line that says DEFINES+=-DRGB_SLOWDOWN_GPIO=1 and change 1 to 2
Press ctl-o and hit enter. Press ctl-x

cd ..
sudo make

cd /opt/fpp/src
sudo rm fppd   (dont worry if you get an error indicating file does not exit just continue to next step)
sudo make

close the SSH Shell
click restart FPPD in FPP
you may need to close the browser and reopen or reboot the Pi for the changes to take effect.

I still think it would be good if we could update the matrix library to the latest version and add these options to the LED panel settings.

I will be very busy getting other things ready so I don't if I will have any time to do any more with it before Christmas. But, the above changes at least seem to provide a working solution to the problem.
Thank you, I will try this. I really appreciate the help. 

Sent from my SM-N920P using Tapatalk


Offline dkuntz

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 13
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #26 on: September 12, 2017, 07:27:30 PM »
Just wanted to let you know this solution worked for me. I ended up with panels from two different suppliers. The first panels I got had a slight ghosting around text. These were the ones I posted before that lowering the voltage remedied. The panels from the other source had much worse issues with not only ghosting but major flickering of parts of the text. These were not fixable with voltage changes. Using both your changes has solved any issues with both sets of panels. Thanks!

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #27 on: September 12, 2017, 07:52:42 PM »
That is very encouraging news. I haven't had a chance to try it yet. ( Work and family, don't they know what time of the year it is?).

Offline Wichita

  • Newbie
  • *
  • Join Date: Dec 2015
  • Location: Andover Kansas
  • Posts: 16
  • Kudos: 0
Re: P10 panel flickering outline
« Reply #28 on: September 13, 2017, 06:59:14 PM »
This worked for me too.  Thank you, thank you, thank you.

Offline rmp2917

  • Newbie
  • *
  • Join Date: Aug 2014
  • Location:
  • Posts: 30
  • Kudos: 1
Re: P10 panel flickering outline
« Reply #29 on: September 30, 2017, 11:13:09 PM »
I have made the necessary changes on my local setup to upgrade to the latest Pi RGBMatrix library and added the new settings to FPP. It seems to be working without any issues.

I would like to share this update with anyone that is interested. However, I am not sure what I need to do to push these updates to the server or how to create a new branch. If someone could let me know how to do this, I would be glad to share it.

 

Back to top