pikvm/docs/pass.md

HDMI Video Passthrough

This is a new exclusive feature available only on PiKVM V4 Plus. It allows you to connect PiKVM to the gap between the target host and the display. Thus, PiKVM does not interfere with the normal operation of the display and passes the video signal through itself until you need remote access via PiKVM In this case, PiKVM directs the video stream to the Web UI or VNC.

!!! info

* The passthrough feature supports a screen resolution **up to 1920x1200** pixels.
* Other PiKVM devices besides V4 Plus do not support the passthrough due to hardware limitations.

This is shown more clearly below:

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Setting up the passthrough

1. Connect the display to OUT2 port on the back side of PiKVM V4 Plus.

2. Update OS and reboot:

   {!_update_os.md!}

3. Switch filesystem to RW-mode:

   # rw
   

4. Add these lines to /boot/config.txt:

   dtoverlay=vc4-kms-v3d
   disable_overscan=1
   

5. Enable the passthrough service:

   # systemctl enable kvmd-pass
   

6. Perform the soft reboot:

   # reboot
   

After rebooting, you will see an image on the display. If you open the stream in the Web UI or VNC, the image on display will be temporarily stopped and redirected to the remote access session.

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Current limitations

Please note the feature is still new and will be improved.

• The video cannot be shown simultaneously on the display or in a remote access session. During a remote session, you will see the STREAM IS ACTIVE text on the display instad of image.

• Audio is not supported at the moment.