No Signal when recording from Linux to Windows using Elgato

Please note, this article doesn’t address recording or streaming using an Elgato card on Linux. Rather, this article discusses capturing output from Linux to Windows. With that setup, I ran into an issue where I received a ‘No Signal’ when attempting to record from Linux to Windows using an Elgato card. This article discusses why I ran into that issue and how to potentially fix it.

Setup

My setup is as follows. I have a Linux Desktop running Ubuntu 18.04 LTS, Gnome Display Manager and a Nvidia graphics card. My Windows machine has the Elgato capture card, which has two HDMI ports, an input and an output port.
The Linux machine is connected to the input and the monitor is to the output.

After all the hardware was connected, I installed the OBS project software, but regardless of the changes I made, I received a ‘No Signal’ when attempting to record from Linux. Additionally, the monitor that was supposed to show the content of my Linux screen was complaining that it wasn’t receiving a signal.

Testing different devices

After having done some debugging and determined that my setup should work, I decided I would try to connect something else. Perhaps the issue was with the Linux machine and not the Windows setup or capture card? I hooked up a Raspberry PI and instantly got output both on the OBS software and the monitor. To make sure that it wasn’t just the PI working, I also tried a Jetson Nano. Once this worked as well, I determined that the hardware setup was working and that it had to be a software issue somewhere.

After some research on capture cards, capture software, capturing gameplay from consoles such as PS4 and XBox, I had an idea of what I thought might be the issue.

Some background on HDCP

So, HDCP stands for ‘High-bandwidth Digital Content Protection’ and “is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio & video content as it travels across connections.” What it does is make sure that, before sending copyright protected data, such as content from streaming services, the receiver is authorized to receive the data. You can read more about this from the Wikipedia site, but briefly, the Elgato capture card stops you from receiving any content that is marked as copyrighted.

On consoles such as PS4 and XBox, the HDCP protocol is only initialized when copyrighted content is viewed. So for example, HDCP would be on if you are streaming Netflix from your console. Then, when the console is used to play games, HDCP is turned off, allowing the user to capture gameplay. This is because gamplay is not copyright protected. As far as I know, Windows works much the same way. Deactivating HDCP when there is no copyrighted material accessed and then activates HDCP when copyrighted material is accessed.

Linux and HDCP

As far as I know, HDCP support was only recently added to Linux. And I believed that the inclusion of HDCP in Linux was the problem. Apparently, both the Raspberry PI and Jetson Nano doesn’t support HDCP. However, I believe the display manager did support HDCP and the way it was implemented may have been the issue.

I’m guessing the display manager was set to have HDCP turned on all the time. That way, it did not need to determine if the user was looking at copyrighted content or not. In other words, regardless of what was displayed, the default was to treat it as copyright protected material.

Once I’ve determined display manager might be the issue, I did some further investigating. I came across an article on Wayland which I thought might address the issue I believed I had encountered. Furthermore, it turned out that Wayland was included in the 19.10 release of Ubuntu.

Based on that, I determined to give the Ubuntu 19.10 Desktop a shot. After it had installed with default settings and rebooted, the OBS software received a signal and my monitor displayed the log in screen. So, changing the Ubuntu version resolved the ‘No Signal’ when recording from Linux to Windows using Elgato.

Summary

The next step is to update to 20.04 because 19.10 support officially ends in July of 2020. In the meantime, I’ll start recording content and posting it here. If you want to keep up to date on any video releases and the Bacula video course, be sure to sign up to the mailing list.

I hope you’ve found this article useful. Any questions, comments, suggestions, errors or changes, leave a comment in the comment section below. You can also send me an email using the link on the left.