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Ask HN: Offline video call via HDMI cables

3 points by pnnp ↗ HN
Our conditions force us to make video call between 2 rooms almost every day for learning and teaching.

We don't have a good Internet connection here.

However, we do have 2 long HDMI cables, 2 HDMI TV, 2 laptops.

So we are trying a very simple approach that is just connecting them like the following illustration.

Room A Computer ]-- HDMI Cable --> Room B TV

Room A TV <-- HDMI Cable --[ Room B computer

Then on the 2 laptops, we just use a simple WebRTC like this one:

https://webrtc.github.io/samples/src/content/devices/input-output/

to stream the video & voice call to each other.

The WebRTC does have echo problems with computer built in microphone.

So my question is:

Does any free/open source offline software that can handle this streaming task better then WebRTC, or do you have any suggestions?

(PS: We have Ubuntu OS computers. Just in case, we can also borrow Mac computers).

Thanks HN.

10 comments

[ 3.6 ms ] story [ 33.5 ms ] thread
derane
by the way

and with which program you wanted to make the calls skype zoom and so on will not work offline

pnnp
@Thanks Derane, but the device you suggested is only voice call. Not video call. And we wish to make use of our current devices.
formerly_proven
Since you already have an HDMI connection, just extend the display of Room A computer, use OBS or whichever software to fill the screen with the webcam's image, and then monitor your microphone on the HDMI audio output (in Windows this is the "listen to" option), causing the microphone to be output by the TV.
zzo38computer
I fail to see why you need a computer for this; you can just connect a camera and microphone directly to the TV set (or VCR, if you want to record it, I suppose) in the other room, and then just do that both ways.
pnnp
Dear ZZo38computer, Yes, this is a very good solution. We thought about this too. However, we could not do here because we do not have all such things. Thanks ZZo38computer
pnnp
Thanks all,

So for this time being, I may just use a simple WebRTC with an external microphone.