Reading Latency Information from a Device

HDMI / DisplayPort EDID

Some devices may report their audio and video latency information via EDID for the audio/video signal and display mode that is used when the device is started.1 In some cases, the EDID reported latency information might be skewed towards a longer latency to account for varying latency of different display modes.2 For this reason it is recommended to not rely on EDID latency information being accurate for any specific display mode.

HDMI CEC Messages

Author’s note: It may be possible to read “dynamic auto lipsync” latency values reported via CEC messages using a tool such as the Pulse-Eight USB – CEC Adapter. Software would be written using the libCEC library to make for a fast and easy way to read this latency information.

If you are interested in writing this software tool to use with a USB CEC adapter, please let me know; I would love to collaborate and include instructions on how to use your tool on this page.

Last updated on September 29th, 2021.

  1. HDMI Specification 2.0, Section 10.6.1 “EDID Latency Info”
  2. HDMI Specification 2.0, Section “Supporting a Range of Latency Values”