Basic lecture recording with OBS Studio

The Opencast player on Moodle allows for two synchronous side-by-side videos, intended to show a speaker beside their slides. To capture such video, we need to record these separately: Here are the steps to do this with Open Broadcaster Software (OBS) Studio.

EdTech ProLehre
14 steps
41 seconds

Obsproject

We can consider three main types of video filming: 1. single image source (a speaker OR their slides) 2. one combined source (the speaker on top of, or next to, their slides) 3. multiple sources (a speaker separate from their slides; plus maybe audience feedback, a leaderboard, an external reference, a view of the public, ... ) Case 1 is just a simpler case of Case 2, requiring less setup, so those will be treated together. For Case 3 however, there are two approaches differing in complexity, so we will deal with it at the end. Where OBS Studio shines is streaming/ hybrid lecturing/ remote teaching: \ To have **multiple prepared setups, but only broadcasting a single one at any given moment, and switching between them**. Typical setups are: a 'waiting screen', with maybe title and times and a countdown timer to the start; a view of the slides; a view of the speaker(s); a view of the slides but with a smaller view of the speaker on top of them, positioned so no important parts of the slides are covered; a view of the public; ... However, **there is no editing** in OBS Studio: For lecture material videos, you will probably need to trim off the beginning and ending, and maybe cut out some 'dead air' between scenes; so an app like [[\[\[\[Camtasia\]\]\]]] must be used.

First to install: Go to <https://obsproject.com/> and download the appropriate version (Windows, MacOS or Linux). Running the installer, a wizard will ask whether you are mostly interested in video recording (so, best quality your hardware can manage) or streaming (so, best quality your data bandwidth can manage). If you find yourself in the first situation described above (wanting to film a single source), you probably can look at the Quickstart Guide (4 steps) and be done: You may not need any what follows below! Otherwise, read on...

**Install the Source Record plugin:** On the same OBS website, search for <Source Record>, or go to **Resources** > **Plugins** and browse until you find the Source Record plugin. Then choose the correct version (Windows installer, or MacOS or Linux), exit OBS, double-click to install the plugin, and restart OBS.

Starting up OBS, we see *five basic blocks* at the bottom: We can normally ignore **Audiomixer** and similarly leave **Scene transitions**/**Szenenübergänge** on its default. We will spend most of our time on **Scenes**/**Szenen** and **Sources**/**Quellen**, but first we have to go to the **Controls/Steuerung** block, where we open the **Settings/Einstellungen** to define what type and shape of output we want.

Most of the values here in **Settings/Einstellungen** have been set silently by the wizard at the start. Two main exceptions: Firstly, you can change the **Language/Sprache**, under **General/Allgemein**. Secondly, under the **Video** tab you need to *decide the size (in pixels) of your recording*. This consists of two parts: The resolution it internally works with, and the output. First you set the **Base (Canvas) / Basis (Leinwand)**: The drop-down menu offers the reasonable values for your setup. Ideally you choose the highest available resolution, depending on your sources. In my case: In this case, I'm working from a small laptop with built-in webcam, connected to a widescreen monitor with a USB webcam balanced on top. So the three values detected in the example below are (from bottom to top): - 1280x720px: The resolution of my laptop screen and my built-in webcam. Both are unused, as I've closed the lid of my laptop and connected an external monitor plus webcam. - 1920x1080px: From my USB webcam. Note it has a higher resolution, but the same width-to-height proportion of 16:9 as the laptop screen. - 2560x1080px: From my widescreen monitor. Note this is much wider than the previous 16:9 options, at close to 21:9. *It's 64:27, to be precise.* Your choice from the above will normally be 1920x1080px, since this is the default proportions of a laptop screen and of slideshows. *You can choose your own value (in the screenshot: 4480x1080pixels) instead if wanted.* Once the base canvas size is chosen, check and if needed edit the next item, the **(Scaled) output resolution/(Skalierte)Ausgabeauflösung**. This will by default be the same. However, if you need to save or stream the movie in a lower resolution (for example, in 1280x720px) then you set that limitation here. *If they differ, make sure **base** and **output** have the same proportion!*

Now we can finally set the two remaining blocks on the main screen: **Scenes** and **Sources**. *In our situation, the next step will look needlessly complex and redundant; but this stems from the fact that OBS Studio is designed for much more complex filming. The following may help to understand the intent:* *An example of a 'Scene' would be a current affairs report on TV. The studio view has a presenter and interviewee, with below a title showing the current topic and the interviewee's name and affiliation; plus a screen showing a reporter on location; and maybe below a 'ticker tape' with running news headlines. All the pieces making up this 'Scene' come from multiple distinct 'Sources': Studio camera, close-up cameras for both speakers, plus outside location camera, news ticker, and topic/title/ID overlay.* In the much simpler situation we are dealing with, we must therefore define two Scenes, each with one Source.

We can start by right-clicking on the existing default **scene** and choose **Renaming/Umbenennen** to give it a more practical name like 'Speaker' or 'Webcam'.

With the Scene still selected, click the '+' to add a **Source/Quelle** to it: This brings a long list of possible types of sources, in our case a **Video recording device/Videoaufnahmegerat**.

We have not yet defined a webcam (including its properties), so we choose **Create new/Neu erstellen** and can again choose a more intuitive name (for example, the brand or model name) to avoid mistakes later.

We are offered three 'Camera' sources: - My laptop's built-in 1280x720px: "HD User Facing". *The name is given by hardware itself (not by OBS); as mentioned with the Canvas size choice, the laptop is closed so it films nothing; plus it's poor quality.* - A virtual camera: "mmhmm Camera". *This is for the simple mmhmm plugin, doing a similar overlaying-webcam-over-desktop, useful for e.g. Zoom/Teams/... .* - My intended 1920x1080px webcam: "Logitech BRIO". So we choose the last option. *The available settings default to sensible values so can be ignored.*

We must tell this Source to save its recording separately: Right-click on it and select **Filters**, which opens a dialog.

The filters are divided into two groups: Audio/Video Filters (noise suppression, audio compression, equalizers), and below that **Effects Filters**. Click on the '+' to add and configure a new one, and choose **Source Record** (which is the plugin we installed earlier). We can normally leave its default settings.

We repeat the previous steps to define a second **Scene**, one showing the slideshow: - We add a Scene with the '+' *(instead of renaming the existing default scene)*, and choose a name like 'Presentation', 'Slideshow' or (here) 'Slides', - We add a new Source as before, but now of type **Screen recording/Monitoraufnahme**, give it a helpful name (e.g., 'Desktop' or 'Desktop centre') and from the dropdown choose the only available detected monitor *(our external widescreen one, as closed laptop's screen is inactive).* - With the red control points, we finally drag the image around so it is centered on our canvas. *The striped/hatched area will not be filmed; but a default slideshow has the same 16:9 proportions as the canvas, so the striped areas are empty during slideshows. We also don't have to scale the monitor using the red corners, because we chose our canvas to have the same vertical resolution as the monitor.* - We add the **Source Record** filter also to this source.

This concludes the setup, and lets you start/stop recording in the **Controls/Steuerung** block. Once the 'live' cast is over, you can edit the resulting video in any video editing software you are familiar with. Obvious choices are Capcut, Davinci Resolve, or Camtasia (which has a TUM license); and on MacOS: iMovie.

Basic lecture recording with OBS Studio

EdTech ProLehre
14 steps
41 seconds

Obsproject

We can start by right-clicking on the existing default **scene** and choose **Renaming/Umbenennen** to give it a more practical name like 'Speaker' or 'Webcam'.

With the Scene still selected, click the '+' to add a **Source/Quelle** to it: This brings a long list of possible types of sources, in our case a **Video recording device/Videoaufnahmegerat**.

We must tell this Source to save its recording separately: Right-click on it and select **Filters**, which opens a dialog.