Screen sharing with a USB video capture device

One of the things I noticed on most (if not all) of the RISC OS related Zoom meetings is the very slow screen update when sharing a RISC OS 5.x screen.
Most probably due to having to use VNC to control RISC OS from a machine capable of sharing the screen via Zoom.

One way around this is to use a video capture device in combination with OBS Studio. There are now a lot of cheap Video capture devices that take HDMI as input (including audio) and when connected to USB are then available to preview the screen in OBS studio.
The screen can then be shared via Zoom (or your preferred video conferencing software) with little or no noticable lag. Depending on the quality of the video capture device there can be some compression artifacts on the screen output.

The cheapest ones are around 15GBP. No OS drivers are required. It gets picked up as a Video/audio device automatically in OBS studio.

Search for ‘Capture card usb to hdmi’ on Amazon. These seem to be USB 2.0 (ones which say usb 3.0 are most proably USB 2.0) which is enough for 1080p. Lower quality screen output but OK.

Cheap example here.

or ‘capture card usb 3.0 4k’ for the more capable ones. (around 60GBP) The 4k refers to down scaling the input to 1080p. Output tends to be higher quality but resolution for input/output is restricted to 1080p.

More capable example here.

One way around this is to use a video capture device in combination with OBS Studio.

Or without. Basically, a video capture device is seen as a webcam under Zoom.

The cheapest ones are around 15GBP.

1080p30. Should be enough for Zoom.

Thanks for the advices :)

And possibly use an HDMI splitter before the USB capture so that the RISC OS screen can be seen on a local monitor as well.

The VNC on the Pi4 is a tiny bit better than the Mini.m, but it still seems to be limited by the TCP/IP stack. I suspect we will have to wait for the networking bounty to get decent performance out of it.