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avidiax06/15/20255 repliesview on HN

One caveat of these dummy plugs is that they don't do HDCP. They handle the typical use case of forcing a specific resolution output for headless machines rather well, but fail for the use case that you need to run something that expects HDCP.

This seems a good place to ask: does anyone know of a good solution like this HDMI dummy plug, but that negotiates HDCP? I need to test video streaming apps that require HDCP to play at full resolution, but it is inconvenient to have a full TV for every test.

The one solution I've found is an HDMI multiviewer, which seems to negotiate HDCP to each port individually.


Replies

ndiddy06/15/2025

I use this HDMI splitter. It lets you either set a preprogrammed EDID, or learns an EDID from whatever you plug into HDMI output 1, and then shows up as a connected monitor for as long as the splitter's plugged in without having to connect anything to the outputs. I believe it negotiaties HDCP between the computer/console/whatever and the splitter, then sends the signal to the output monitor without HDCP. https://www.amazon.com/dp/B07VP37KMB

amelius06/15/2025

I have a different usecase. I have an embedded system that sends out HDMI. However, its boot screen is something I want to replace by another HDMI stream (a static image would suffice). I specifically don't want to change anything on the embedded system for a thousand reasons I won't go into. How do I cheaply and robustly do this?

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hedora06/15/2025

Aliexpress sells things that claim to terminate hdcp and forward hdmi. Caveat emptor.

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mschuster9106/15/2025

Try one of these HDMI splitters that are more or less openly advertised as "HDCP strippers" on Amazon.

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dcan06/15/2025

Terminating HDCP is difficult, you’d have to downgrade it to HDCP 1.4 and then have a 1.4 ‘compliant’ (see: device on the end for it to be a dummy monitor. If you need anything newer than HDCP 1.4, it’s likely not possible.

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