Magewell USB Capture HDMI - Can't read device with 2 apps at the same time

[calande]

Hello,

I have a Magewell USB Capture HDMI Gen. 2 and I'd like to read its A/V signal in VLC, and record the stream in an ffmpeg terminal process. I can read the signal successfully in VLC; I can also record the stream with ffmpeg properly. However I can't do both at the same time: I get an error message that says the Magewell USB Capture HDMI is already being used. How to do it? With my other capture board, an Elgato HD60 Pro, I can read the signal with two applications simultaneously.
Thank you

[Cornucopia]

The Magewell is just like any other USB device that utilizes UVC - it is only available to ONE application, which takes full control of the resources.

Your Elgato is a PCI-type card, and so it necessarily isn't hindered by UVC/USB. It is a bit unusual for that to be available, though. Perhaps it is using VFW vs. Dshow vs. MediaFoundation vs 3rd party channels.

Regardless, you SHOULD be able to utilize the output of that USB card in 2 applications if you insert an intermediary "shim" in the form of a Virtual (web)cam. So, in essence, the USB device is being used solely by the Virtual cam driver, and the virtual cam is designed to allow for multiple output nodes. (some can, some cannot)

I do exactly this kind of thing using Zoom, Panopto, OBS, etc. (I too make use of Magewell USB Capture HDMI gen2 boxes).

Most Virtual cam drivers also have the capability of adding overlays (text, etc) onto the stream as well. Note: there is a penalty of additional latency when you go down this route.


Hope that helps,

Scott

[calande]

Thank you Scott, yes, that helped. I'll install a virtual cam in-between