This page explains the setup and how-to guide for the OBS broadcaster. This person manages the technical setup of OBS and thus the streaming. This person often is, but does not have to be, the OBS director [todo: link] who switches the scenes and manages the broadcast after it has started.

Role of the broadcaster

As the broadcaster, you manage the OBS application that captures Zoom and sends it to the world. This is different from:

  • The Director manages the scenes and the overall flow of the workshop (switches scenes, cues instructors when to start talking, shares HackMD during the breaks). This person is often the broadcaster, but for clarity we use more precise terms.

  • The Host is the interface between the instructors and the audience: e.g. announcing instructors, keeping to the schedule, etc.). They are very often the same as the Director.

  • The Instructors connect to Zoom and teach. If there is no designated director, at least one instructor needs to know a bit about that.

The broadcaster has a lot of preparation work to do the first time they get set up (future courses aren’t so bad). They should expect some panicked fixing of stuff right before each course starts. During the courses themselves, the broadcaster is mainly sitting back making sure nothing breaks.

Initial setup


  • A somewhat powerful computer dedicated for broadcasting (not used for teaching as an instructor, the broadcaster can use an instructor computer, but that is much more complicated).

  • Stable internet connection (speed is not too important these days).

    • 20/5 download/upload Mbps is probably plenty good. 100/10 Mbps is far more than is needed.

    • Wired connections, rather than wireless, are better (WiFi, non-cellular uplink). However, you probably know your overall stability the best: you want a continuous, smooth connection without much jitter. However, OBS settings can be tuned to have a larger buffer to handle this.

Software installation:

  • Install OBS (Linux, Mac, Windows - this is a mass market product so there is good support)

  • Install obs-websocket. This is also fairly widespread, but slightly less so than OBS.

  • Zoom (but you likely already have that)

Zoom setup:

  • Install Zoom. There’s not much you need to do differently.

  • Some Zoom settings:

    • General → Use dual monitors → yes. Despite the name, this gives Zoom two windows: one for the gallery view, one for the screenshare (or active speaker if there is no screenshare).

    • General → Enter full screen automatically when starting or joining a meeting → false

    • Screen Share → Enter full screen when a participant shares screen → false (important)

    • Screen Share → Scale to fit shared content to Zoom window → true.

OBS setup:

  • Clone the obs-scenes repository. This contains some pre-made scenes which will set your OBS up for teaching nicely.

  • Import the TeachingStreaming profile (Profile → Import → obs-scenes/profiles/Teaching_Streaming). This contains things like audio and encoder settings

    • TODO: this may need adjustment for your particular situation. At least things like file paths will need to be adjusted. Look at the obs-scenes readme for more information.

    • Most importantly, this sets it to 840 horizontal × 1080 vertical (portrait mode).

  • Import the Teaching_Streaming_ZoomCapture scene collection (Scene Collection → Import → obs-scenes/scenes/Teaching_Streaming_ZoomCapture).

  • You now need to configure some window captures, for example, you need to tell OBS which window has the gallery of all instructors in it. From the “Scenes”

    • Scene _GalleryCapture[hidden] → source ZoomMeeting-Gallery right click → Properties → Window → select the Zoom gallery view (for me it is titled “Zoom meeting”). TODO: adjust the size of this window until it fits the pre-made scene [it looks nice and large]

    • Scene _Screenshare-Zoom-Capture[hidden] → source Zoom-SecondWindow right click → Properties → Window → select the Zoom screenshare/active speaker window (for me it is titled only “Zoom”). Adjust the size of this window until it nicely fills the preview pane (the ideal size is 840×1080).

    • (optional) Scene _Hackmd-Capture[hidden]: similar, select the shared HackMD

    • (optional) Scene _Broadcaster-Screen[hidden]: configure your local desktop capture.

  • Configure the audio

    • Settings → Audio → Desktop Audio → “Default” (or if you want, select an explicit device). This is what will capture Zoom by monitoring your speakers/headphones.

      Note: prevent audio feedback! Be careful if you set this to speakers, and you have a separate computer which you use for teaching with a microphone that would hear those speakers: you would get feedback.

    • Settings → Audio → Mic/Aux Audio → “Default” (or whatever device you want). This would capture that computer’s local microphone, if you use it. (More likely, you would join the meeting as an instructor, and thus use a separate computer to speak to people)

    • From the main OBS scene, rename the audio devices:

      • Bottom panel → Audio mixer → one of the devices → gear icon → Rename →

        • Desktop capture to “Instructors”

        • Mic to “BroadcasterMic”

  • Configure obs-websocket (set the listening socket + authentication).

    • Tools → Websocket server settings → {Enable websockets server=true, Server port=(something), Enable authentication=true, Password=something}. Share your IP address, server port, and password with your other instructors.

  • Allow outside connections. On of these two:

    • Use ngrok to forward the connection (including SSL). Read more from the obs-websocket documentation: . Note that the free plan limits to 4 simultaneous connections and the connection information will change every time you restart, which is not great.

    • Configure your router/firewall to allow incoming connections to you IP address, on the port configured above. (it is this external IP address that you need to share with other instructors.

  • Verify the obs-tablet-remote connection (see TODO director-setup).

Before each day

  • Set Twitch stream data: stream title, stream description, channel about page.

  • Configure and check streams

  • Test everything

  • Basic information private message:

    * zoom info:
    * zoom link:
    * attendee hackmd:
    * notes hackmd:
    * live preview:
    * control panel:!auto&host=HOST&port=PORT&password=PASSWORD&config=

Before each broadcast

  • Ensure anything from the above is done (obs-tablet-remote connection, scene layout, etc).

  • Ensure Zoom scenes are correctly captured, flip through them to verify.

  • Wait for first instructors to join.

  • Zoom: Disable sound on participants joining

  • In zoom, right click on a participant without video and “Hide non-video participants”. You may need three participants in order to do this: if you have fewer, join through a browser or something.

  • Make other instructors co-hosts in the Zoom so that they can share screen without the other person stopping.

  • Start recording / start streaming ~20-30 minutes in advance, with audio muted and on the title card scene. Start recording at the same time as streaming so you don’t forget it!

  • Hand it off to the director (possible yourself) to flip the audio and scene once icebreakers start.

During the broadcast

  • You can not share screen with Zoom (it messes up the windows: screenshare becomes gallery, the old gallery window disappears).

    • Instead, there is a separate OBS scene for local screenshare.

    • But we recommend using a separate computer for broadcasting and instructing, to avoid this problem.

  • For the most part, the director does the scene switching (and you might be the director)

  • You don’t need to always be in front of the broadcasting computer, but be available in case there are emergencies.

Common problems

  • Internet connection goes down

  • OBS crashes While this happens somewhat often during testing, during live productions, when the settings are not being changed, it has never been observed. Set all settings in advance, and maybe quit and restart right before starting the broadcast.

  • Audio is capturing the wrong inputs, or audio quality is bad

    So once when broadcasting, the audio quality was horrible. It turned out that the sound system got confused and the desktop audio capture (zoom capture) was actually capturing the microphone. This was not reflected in the OBS settings.

    To solve this, go to the OBS settings (you can adjust most, but not all, settings while a stream/recording is ongoing). Flip the audio devices to “disabled”, then back to what it should be (possibly you need to save in between?).

    It’s possible there are other times you need to adjust the audio.

  • I have HackMD open in view mode (to share) and HackMD open in edit mode (to edit), but OBS keeps switching to share the editable one. OBS seems to go by window title. Try this: Use a different browser, or run one of them in private mode (so that the title is different).

See also

  • There is plenty about OBS and streaming online, since it is a big business now. You can find answers to most questions once you know the basic theory.