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ISSUE Delay in leds from what is displayed using video grabber

Discussion in 'Hardware Support' started by Zaborejszyn, 5 October 2020.

  1. Zaborejszyn

    Zaborejszyn New Member

    The main reason I installed ambilight using Hyperion was to bypass the HDCP protocol when I watch netflix from my computer in full resolution. Previously, I used software similar to Hyperion cature software, but whenever I turn on the hdcp content, the signal is blocked by such software.
    I put the hyperion on the raspberry pi 3, I stream the leds through the GPIO pin (ws281x) and use a common video grabber like this one.

    Noticeable time interval in leds than what is happening on the screen, around a second, which is quite distracting as scenes change etc.
    I reduced the resolution of the grabber to 360p, size decimation is 8 (increasing the value does not bring the desired results), I was also afraid of the "smoothing" settings, reducing the Time value to 50 which improved the performance a little but the delay is still strongly felt.
    I was starting to think that this could be a problem with such a video grabber.

    I also noticed that using the Hyperion screen capture delay is not noticeable at all, which surprised me a bit (raspberry pi is connected by WLAN) but with this solution I can not enjoy the full resolution of the content and the LEDs on the back.

    Can you recommend any video grabbers without delay that would work on the usb 2.0 interface? Does it make sense to buy a usb 3.0 grabber for raspberry pi 3 which only has usb 2.0? (pls with HDCP support)
  2. lcnobo

    lcnobo New Member

    RPi1/Zero, RPi3, +Arduino, +PhilipsHue, +nodeMCU/ESP8266
    It is possible that delay is from ws281x library? It is recommended to use dedicated arduino or like device led controller but without further testing, it is hard to say where the bottleneck is
  3. jeroen warmerdam

    jeroen warmerdam Raspberry 3B / APA102 / WS2801 / Hyperion.NG

    maybe has to do with PI arm and power settings, thats all i can think off. (cpu cant render the images at full speed) ?
    look at the bold sections that is important for higher clockspeed and usb power on the PI
    in .txt on config SD card;.. (this is mine)

    # For more options and information see
    # http://rpf.io/configtxt
    # Some settings may impact device functionality. See link above for details

    # uncomment if you get no picture on HDMI for a default "safe" mode

    # uncomment this if your display has a black border of unused pixels visible
    # and your display can output without overscan

    # uncomment the following to adjust overscan. Use positive numbers if console
    # goes off screen, and negative if there is too much border

    # uncomment to force a console size. By default it will be display's size minus
    # overscan.

    # uncomment if hdmi display is not detected and composite is being output

    # uncomment to force a specific HDMI mode (this will force VGA)

    # uncomment to force a HDMI mode rather than DVI. This can make audio work in
    # DMT (computer monitor) modes

    # uncomment to increase signal to HDMI, if you have interference, blanking, or
    # no display

    # uncomment for composite PAL

    # uncomment to overclock the arm. 700 MHz is the default.

    # Uncomment some or all of these to enable the optional hardware interfaces

    # Uncomment this to enable infrared communication.

    # Additional overlays and parameters are documented /boot/overlays/README

    # Enable audio (loads snd_bcm2835)

    # Enable DRM VC4 V3D driver on top of the dispmanx display stack


    • Informative Informative x 1
  4. Zaborejszyn

    Zaborejszyn New Member

    I tested without the expected results even with the bitrate set to 500,000
    I also tested it without the expected results, I can still see a ~second delay in what is displayed on the screen and the responses of the leds.

    Looking at these tests, I suspect a video grabber even more.
    Let's also take into account that the video grabber I ordered came in a different shape than on the website (more slim with no scraps on the sides like a USB flash drive). Maybe these "basic and cheap" noname video grabbers are like a lottery, and it could get better or worse.

    Hence my request, could you recommend a good video grabber that you use yourself, for example?

    I am looking for something with good latency and comatible with usb2.0

    It may be worth mentioning that I do not use any video splitters etc. The signal goes directly from the computer's graphics card via HDMI and the signal to the monitor via Display port (duplicate screen on outputs)
  5. jeroen warmerdam

    jeroen warmerdam Raspberry 3B / APA102 / WS2801 / Hyperion.NG

    on Rpi3/ hyperion.NG / Buster

    I am using a HDMI to RCA analog converter > to UTV007 ( really simple grabber, like 8 euro's) on USB2.0, i show you my settings of the ledconfig
    size decimation is between 3 and 4

    • Thank you Thank you x 1
  6. jeroen warmerdam

    jeroen warmerdam Raspberry 3B / APA102 / WS2801 / Hyperion.NG

    you can check latency by looking at your tv channel and at the same time to Led Visualisation/ live video. If there is lag there the tv channel must be faster then the rendered image to Hyperion.