3-cam streaming with laptop?

[toke lahti]

Hi,
I should gear up for simple cheap streaming set and was wondering when usb3-bus on a laptop becomes a bottleneck?
Anybody tested how 3 hdmi-usb-dongles work with together?
Anybody seen any reviews on this?

If the dongle receives 1920x1080p@30fps 4:2:2 that's 995 Mbit/s, per dongle, right?

 

[My Living Room: Live!]

We use 3 cameras in our stream, all from a laptop.

Logitech C920 via USB at 1920x1080 plugged directly into laptop
Logitech C930e via USB at 1920x1080 plugged into USB-C hub
Built-in laptop webcam at 1280x720

 

[toke lahti]

Thanks for the answer!

I guess the internal webcam is also in the same usb bus.
Is there any kind of internal compression in these webcams?
If they are sending 4:2:0, that would mean 746 Mbit/s per camera if otherwise uncompressed...

Your example shows that usb bus can handle your cams, so at least, that's good to know.

 

[qhobbes]

Is there any kind of internal compression in these webcams?

See the "Decode Mode Support" section on

CAPTURE CARD DOCUMENTATION - Latency, Decode Modes, Formats, & MORE!

TABLE OF CONTENTS Intro/Overview Decode Mode Support Notes on RGB Color Space Format Support Notes on Scaler Support Input Latency Testing Notes on “Bitrate” support Testing Methodology Limitations & Future Improvement How to submit capture...

obsproject.com

and https://obsproject.com/forum/threads/i420-mjpeg-xrgb.62400/