This purpose of this article is to give an overview of possible issues with EDID manipulation operations on our new AVA-EX HDMI extenders. Source resolution is based on EDID presented by a downstream device. However, sources may behave differently when presented with the same EDID. If a source output is 3840x2160 p60 YUV444/RGB 8bpc the result will be no video signal downstream. Extensive work has been done to manipulate the EDID so this does not happen (default mode), but Atlona QA has discovered that in certain situations a source will output a signal that goes beyond the limits of HDBaseT. This issue most commonly happens when HDMI 2.0 source is extended over HDBaseT to an HDMI 2.0 display and the display presents an EDID with a preferred timing in excess of 340 MHz (pixel clock). We observed this when certain displays have enhanced mode enabled by default and do not allow for it to be turned off. There are other articles that elaborate on the issue with enhanced mode. The following EDID example would result in no video signal downstream with certain sources.
Future firmware will address this issue! Until that time a workaround has been built into 1.0.0 firmware for all AVA-EX extenders. This replaces the EDID that is presented to the source with an EDID that contains a preferred timing of 3840x2160 p30 YUV444/RGB 8bpc (pixel clock: 297 MHz).
To switch between default dynamic EDID and this static mode:
Hold TEST Button for more than 20 seconds but no more than 30 seconds, then let go and look for:
- TEST LED blinks 5 times = Static EDID (ATL 2160P 2CH) is being used (stored on HDBaseT RX)
- TEST LED blinks 3 times = Dynamic EDID manipulation is being used (default mode) This means that downstream EDID is being modified on the fly to remove all HDMI 2.0 bits that may cause a source to output a video signal with timing above 340 MHz (pixel clock).