Black image from capture card

  • Hello,


    Recently, my SD card has failed, leading me to reinstall Hyperion on my rpi3 and stumbled upon an issue i couldn't resolve, no matter google searches or AI help: no output from the USB capture card.


    Parts:


    - cheap AliExpress USB capture card (changed it, same issue)

    - powered HDMI splitter from AliExpress ( working, outputs the image from laptop-> TV)


    What I've tried:

    - Change the capture card to the same model and to another model, still black image.

    - ffplay and v4l2-ctl:


    USB Video: USB Video (usb-3f980000.usb-1.4): /dev/video0 /dev/video1 /dev/media2


    libavutil 57. 28.100 / 57. 28.100

    libavcodec 59. 37.100 / 59. 37.100

    libavformat 59. 27.100 / 59. 27.100

    libavdevice 59. 7.100 / 59. 7.100

    libavfilter 8. 44.100 / 8. 44.100

    libswscale 6. 7.100 / 6. 7.100

    libswresample 4. 7.100 / 4. 7.100

    libpostproc 56. 6.100 / 56. 6.100

    /dev/video0: Device or resource busy


    - tried setting up mmpeg or yyuvm, framerate changes from 5 to 20

    -capture card is active, selected, and detected

    - signal detection on and off

    - As input, I was and am using a Google TV 4k, tried with a laptop as input, nothing changed

    - installed Hyperion as a service from RPiOS Lite and downloaded and installed the standalone image - nothing changed

    - tried multiple resolutions



    Also, when selecting the ws281x in the LED output, by default, I'm not able to use it because I'm not root - I have to grant it manually.


    Mainly, I have changed nothing in the config compared to the previous config, before the SD card failed; however, it's not working.


    Am I missing something or doing something wrong?


    Thank you very much!

    • Best Answer
    • Official Post
    Quote

    Black image from capture card

    If the grabber produces a black image, it is likely that the the brightness is set to zero.


    To get this corrected:


    a) Switch to Expert Setting

    b) Check the Control values (see 1.)

    c) Press Button "Default Hardware controls" (2.)


    d) The Control Values should have changed (3.)




    e) Click Save (4.)


    Would be great, if you could report back, if that worked.


    I updated the Release notes to ensure that people can find this easily.

    Quote

    You should now see a non black image in the preview. when selecting the ws281x in the LED output, by default, I'm not able to use it because I'm not root

    see the documentation on PWM Prerequisites (Controller type RPi PWM/ws281x) and the link how to change the service user.

  • pclin

    Selected a post as the best answer.
  • I feel dumb, this fixed my issue have been trying to figure out why this was not working. Changed the brightness settings under the expert setting level and fixed my issue. Thanks alot, life saver. :)

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