coreelec:video_disp_cap

What is EDID?

EDID (Extended Display Identification Data) is an industry standard for AV Source and Display devices which automatically communicates manufacturer specifications and other data between devices. This allows an AV source to send the best compatible signal data to the display unit, ensuring the best possible picture results.

Isues

Display devices can have various levels of EDID implementation and, in some cases, may lack EDID information altogether. Such inconsistencies may cause operational issues, ranging from overscan and resolution problems to not displaying the source content.

A workaround for these scenarios is to override the resolution for CoreELEC by using a disp_cap file.

Use this method only when absolutely required

Remember to remove the override prior to switching to a different display device

This function is only available with Amlogic-ng!

Overriding EDID

  • connect the SBC or Set Top Box directly to the display device with a Certified HDMI cable.
  • power on the display device
  • boot CoreELEC
  • SHH into CoreELEC
  • execute:
cat /sys/class/amhdmitx/amhdmitx0/disp_cap > /storage/.kodi/userdata/disp_cap

This will create a copy of the file disp_cap in the Configfiles folder.

Fixed resolution

To set a fixed resolution, edit the disc_cap file to include only the desired resolution.

Example: 

nano /storage/.kodi/userdata/disp_cap

1080p50hz

Removing the override

  • SSH into CoreELEC
  • delete the disp_cap file located in /storage/.kodi/userdata/

Example: 

rm /storage/.kodi/userdata/disp_cap

More on EDID

This article by Extron Electronics covers EDID in great detail.