Unstable HDMI - CSI Extension, Official V3 Camera, 2m HDMI Cable

  1. Where did you get the camera module(s)?

  2. Model number of the product(s)?

  3. What hardware/platform were you working on?
    bullseye rbi4b8gb

  4. Instructions you have followed. (link/manual/etc.)
    Wiki + RPi V3 Guide

  5. Problems you were having?
    Unable to find camera, or framerate crashes to near zero, or VL42 error unable to confirgure device or set parameters.
    Basically libcamera apps have a high probability of stalling, or failing initially.
    Vl42 msg seen regularly: ERROR V4L2 v4l2_device.cpp:352 'imx708': Unable to set controls: Input/output error

  6. The dmesg log from your hardware?
    [ 7.313014] imx708 10-001a: camera module ID 0x0301
    [ 7.318672] imx708 10-001a: Consider updating driver imx708 to match on endpoints

  7. Troubleshooting attempts you’ve made?
    rebooting, running with -v2, trying without preview and awb/autoranging, varying timeouts.

  8. What help do you need?
    Is there a way to call the libcamera apps with an error-tolerant flag to skip frames/hardware faults? (It often fails to take a photo due to viewfinder failing part way through when frames get low / errors occur)
    Is there a way to reboot the camera/interface without rebooting the device? (It sometimes seems to reach an unusable state)

Using the vlc tcp streaming for infinite video from the Rpi guide (official instructions) seems to be most reliable, but still breaks sometimes more than others. Touching things seems to make reliability less.


You used imx708 and extended scheme. Now it’s up to you to isolate the problem.

  1. Will there be such a problem when using imx708 alone
  2. If there is no such problem when using imx708 alone, but there is a problem with the network cable extension solution, then the problem may be caused by the extension solution. Try using a shorter hdmi to see if this problem still occurs (you can Use the 1m long wire we bring by default)

I didn’t get a 1m HDMI cable with my purchase, and the Pi is about 1.7m from the device.

-Edit: Just re-read Edwards message, they don’t state they have the setup only troubleshooting steps-

If you get the change could you try a cable at least 2m (mine could be 2.5m) and go and touch the board with your finger (at the extension end), move it about like on a pan tilt, and do you get any error if you were running libcamera-jpeg in a loop? Also are you using the extra pins and have any extra power source/grounding/decoupling-capacitors etc? and are you using the high bandwidth/resolution modes or a lower mode? I’ve got a 10-15cm CSI/Fpc cable on each end.


In fact, we did a lot of testing. (5m and 10m hdmi)

Hardware Information:
Hardware    : BCM2711
Revision    : c03114
Serial    : 100000007c1d89de
Model : Raspberry Pi 4 Model B Rev 1.4
Kernel version:
Linux Dion 5.15.84-v7l + #1613 SMP Thu Jan 5 12:01:26 GMT 2023 armv7l GNU/Linux

Select the maximum resolution (4608*2592) in the test to preview or save the image.

Preview command:

libcamera-still -t 0 --viewfinder-width 4608 --viewfinder-height 2592
libcamera-still -t 0 --hdr 1 --viewfinder-width 4608 --viewfinder-height 2592

Image saving command:

libcamera-still -t 6000 --viewfinder-width 4608 --viewfinder-height 2592 --width 4680 --height 2592 -o test.jpg

We have tested more than a dozen scenarios, and it is very stable in 5m hdmi.

The hdmi we use is UGREEN, you can also use the same brand hdmi cable for testing.

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