Hi! Thanks a lot for this nice library! I am very happy with the setup. I was able to get my P2.5 96x48px LED matrices working, and it looks very good.
My Goal is to get a long Row. 480 x 48 px. But its too much for one Chain. 4 LED Displays are working fine but with 5 Displays, I have some flickering with playing a video. Already tried some tweaks. (-O/tmp/vid.stream, dtparam=audio=off, --led-slowdown-gpio=4, isolcpus=3) So I divided them into 2 parallel connections. 3 Displays one the first, 2 Displays on the second. Is it somehow possible to get this 2 parallel chains displayed in one long row and not one above the other? (See picture)
Playing my video in right format but some flickering:
sudo ./video-viewer --led-rows=48 --led-cols=480 --led-chain=1 --led-slowdown-gpio=4 --led-brightness=90 --led-show-refresh --led-pwm-dither-bits=1 /home/pi/Quadrat2.webm
Playing the Video in wrong format but no flickering:
sudo ./video-viewer --led-rows=48 --led-cols=96 --led-chain=3 --led-parallel=2 --led-slowdown-gpio=4 --led-brightness=90 --led-show-refresh --led-pwm-dither-bits=1 /home/pi/Quadrat2.webm
I have a Active-3 Bord from electrodragon and a Raspberry Pi 4.
In the meantime, I found a way to get it almost working. Not elegant but almost working. I used your V-mapping option to get the 3 parallel connections in a row.
sudo ./video-viewer --led-rows=48 --led-cols=192 --led-chain=1 --led-parallel=3 --led-slowdown-gpio=4 --led-brightness=100 --led-show-refresh --led-pwm-dither-bits=1 --led-pixel-mapper=V-mapper -f /home/pi/Quadrat2.webm
Because I only want to use 5 and not 6 Led-Displays the video is offset now. Is there a way to get it offset by 48px?
If anyone has an idea for a more elegant way, i would be also happy for advice!
For rPi4 --led-slowdown-gpio=2 is enough, and 1 should work on other ones.
led-pwm-lsb-nanoseconds=50 will be bit faster too
led-pwm-bits=7 will be a lot faster than the default of 11
Otherwise, using active-3 and 3 chains is indeed the best way to get 3x the refresh rate at the expense of longer ribbon cables.
V mapper is a good way to do what you wanted, but indeed parallel chains expect that you have the same length on each chain, which you do not.
Honestly, two things I would consider if you are stuck with 5 panels instead of 6, are
- re-encode your video to add the offset you need
- hack the video player to add an offset at display time (although you might still have an issue with scaling being wrong, in which case you’ll need to go back to #1)
@marcmerlin Thanks for your tips! i tried --led-slowdown-gpio=2 and led-pwm-lsb-nanoseconds=50 but my Led-Displays had problems with this settings.
I tried severel things to add a offset in the video-viewer.cc but was not able to get it done. Do you have a hint what to add?
I’d have to read the code and spend hours on it since I’ve never looked at it.
A quicker way if you only have one video to play or a few, is to re-encode those videos to re-center them so that they magically display where you needed them to
I tought there is the chance, that you are familiar with this specific code and you could give me a fast tip. But I completly understand, I already spent some time trying… Yes the encoding of the video works fine, but i wanted to find a nicer solution. Maybe I have to stuck with this… Thanks for your help anyway!
