Published: Sat 23 January 2021
By C.D. Clark III
In Computer .
OBS stands for Open Broadcaster Software, and it is a cross-platform, open source tool that allows you to control a "broadcast" (a video feed) with many different inputs.
I'm not going to cover how to use OBS, there are all kinds of tutorials on YouTube . This post is just about how to use OBS with Zoom.
I am currently teaching all of my physics classes online, and I have been using Zoom for this. I like Zoom, it has been stable, it runs on Linux, and it supports recording meetings so that I can make
them available to the students that cannot join live. However, screen sharing content and switching between say, lecture slides in a browser and lecture notes in OneNote, is a bit clunky.
I had known about OBS, and even used it to record short demo videos (like the one below) because it does a nice job of screen recording in Linux. But it wasn't until I saw Dr. Jee Hwang's presentation on using OBS for Online Teaching
that I decided to figure out how to use it.
Again, I don't want to explain how OBS works here. Basically, it allows you to take multiple AV sources (web cams, screen captures, window capture, images, text, etc) and combine them into a single video feed. You can then record that video or stream it.
OBS supports dozens of streaming services, including YouTube and Twitch (which is apparently popular with gamers?), but I didn't want to require students to use a new tool/platform. I wanted to keep using Zoom.
It turns out that it is pretty straight forward to do. OBS has an option to output to a "Projector Window". Basically, it just creates a window and outputs the video feed there. Once you have the projector window, all you have to do is select it for you Zoom screen share.
Of course, the window needs to be big so that it will not be pixely on the student's end, so it requires that you have a lot of screen space. I am using a 4K monitor, and I actually have a second, HD monitor as well. The video below shows my setup and
how to stream the OBS output with Zoom
I have also started using OBS to run my "camera" in Zoom for regular meetings. I show this in the video above, but OBS now has a "virtual camera" that you can turn on.
When you turn it on, OBS outputs to a device that looks like any other video source, and you can select it as your camera in Zoom. You do need to install the v4l2loopbackv4l2loopback-dkms.
A few notes on what I have found to work in my current setup:
If you want to show content from a second computer, a laptop for example, you can use OBS.Ninja . It runs directly in the browser and allows you
to stream a screen-share to a URL that you can use as an OBS Browser source. It's pretty slick.
Another option for getting content from another computer into OBS is a USB capture card. I am currently using this for displaying OneNote notes on my Windows 10 laptop
in my OBS instance running on Linux. There is an issue you have to be aware of. Apparently OBS (at least on Linux, I don't know about Windows or Mac) cannot use multiple
video devices on the same USB Bus. Maybe this is a Linux driver issue, I'm not sure, but I had to find a second USB bus on my motherboard in order to use the capture
card and web camera at the same time.
Once you start to understand how OBS works, it opens up a number of possibilities that you never even thought about before. If you have the screen space, I highly recommend it.