How It All Began

I remember that around April or May of the previous year, the daily number of confirmed cases suddenly surged. Taiwan soon entered Level 3 restrictions, and before long, cram schools were officially required to move their classes online.

I had actually been looking forward to online teaching for quite some time. After more than ten years of teaching with a traditional whiteboard, online courses felt like an obvious new direction in a world full of digital resources—but I had never had the chance to try. (Partly because I am lazy... without some external pressure, it is very hard to make myself do something like this XD.) At last, my chance had arrived. How could I not sharpen my tools and give it a shot? Of course, all this experimentation also completely derailed the national exam study plan I had made for May through September—but that is another story XD.

Before deciding on a method, I observed how school teachers and other cram-school teachers were running their classes. Some continued teaching on a blackboard while livestreaming with a phone or tablet—the traditional way cram schools record lessons, and by far the most common approach. A smaller group opened a blank canvas, such as Microsoft Paint, and wrote the lesson content by hand with a drawing tablet.

I considered my own circumstances. I had not yet received a single vaccine dose, so I had absolutely no intention of going out, and my home was too small for another whiteboard. That ruled out board teaching. I did own a drawing tablet because I wanted to learn digital illustration, but my handwriting with it looked almost exactly like my handwriting with a mouse. It was so disastrous that even a friend from the cram-school world could only say, “Uh... how did it end up looking like that...?”

My handwriting with an AREY PF1061 pen tablet. It was so terrible that students would definitely have demanded refunds if I had taught an entire class this way =口=
My handwriting with an AREY PF1061 pen tablet. It was so terrible that students would definitely have demanded refunds if I had taught an entire class this way =口=

After a great deal of testing, I decided to teach with PowerPoint instead. I placed most of the handout content directly on the slides, greatly reducing the amount of ugly handwriting I had to do. I would write only when necessary and treat the occasional ugly note as part of the entertainment (sob). That is how the first version of my online-course slides was born.

All formulas were made with MathType rather than the built-in equation editor. The overall result looked quite good, if I may say so myself.
All formulas were made with MathType rather than the built-in equation editor. The overall result looked quite good, if I may say so myself.

My First Attempt with oCam—and Its Limitations

Because almost everything was prepared on the slides in advance, I could greatly reduce the time spent writing during class. Students still needed time to take notes, of course; there was no way around that. During a livestream, however, this could leave long stretches of dead time while everyone copied things down, which was terribly inefficient. So I thought: why not prerecord the lessons and upload them to YouTube? Students could decide when to watch, when to pause, and how long to spend. I was a genius RRR.

The immediate challenge was choosing a way to record the computer screen while also capturing an external microphone and drawing-tablet input. My first choice was oCam, an entry-level program with simple controls and uncomplicated settings. Its files were not too large, and setting the resolution to 1920×1080 worked perfectly well. That gave birth to the first generation (?) of my online courses.

The first round of online courses. I had three classes at the time, plus another class following a different schedule, so I had to record four lessons every week. I was seriously losing my mind during that period XD.
The first round of online courses. I had three classes at the time, plus another class following a different schedule, so I had to record four lessons every week. I was seriously losing my mind during that period XD.

Every teacher I knew was pulling out their best tricks to find the most suitable way to teach online, so naturally we exchanged ideas. After experimenting for a week or two, I sent one of my videos to a senior teacher in the cram-school world. Their response was:

“No face, too little handwriting, no warmth.”

Warmth?? After thinking about it, I had to admit they were right. A roughly three-hour lesson showing nothing but slides felt like a lullaby. I could not even demonstrate something like Ampère’s right-hand rule, and it did not feel like one of my normal classes. So I began looking for a way to put my own video on screen as well.

Naturally, I first checked whether oCam could do this. It could, but the recorded image could not be positioned freely. Paying for it just for that did not feel worthwhile, so in pursuit of this elusive sense of warmth, I abandoned oCam. You might say, “It is only a temporary online course—why be so particular?”

“If we are going to do something, we should do it as well as we can. That is how we improve.” This has always been one of my principles.

There was another issue: students were not very satisfied with the audio quality. oCam did not provide the audio filters I needed, so changing software seemed unavoidable if I wanted to maintain the quality of the lessons.

My First Encounter with OBS

I was completely stuck on the problem of showing both PowerPoint and a camera image at the same time. Then, while casually opening Twitch to watch a stream, I suddenly realized...

“Wait—doesn’t a streamer show the game, their camera, and the chat all at the same time???”

Searching for “streaming” and “software” led me to Open Broadcaster Software, or OBS. It is used mainly for livestreaming, but why could it not serve as an online-course tool too? Ta-da—an entirely new world opened up. After the online courses settled down, I even used the skills I had learned to start streaming on Twitch, but that is another story... XD

Downloading and Installing OBS

OBS itself is free. Search Google for OBS and it should be the first result. On the official OBS website, choose the download for Windows or macOS. The download starts automatically; once it finishes, open the installer and follow the steps.

I searched for it just to prove that it really is that easy to find XD.
I searched for it just to prove that it really is that easy to find XD.
The official website and the automatic download after clicking.
The official website and the automatic download after clicking.
I installed it on my D drive to save space. Choose whichever location works best for you.
I installed it on my D drive to save space. Choose whichever location works best for you.

Setting Up the OBS Interface and Scenes

The image below shows the basic screen you see when you first open OBS. For the target result, I will use the relatively simple setup from my own online courses. That also keeps this article aligned with its title. If I get the chance, I may write additional articles about other uses for OBS.

Because I use OBS both for teaching and streaming—and tested it again before writing this article—my Scenes panel contains three extra scenes that will not appear in a fresh installation.
Because I use OBS both for teaching and streaming—and tested it again before writing this article—my Scenes panel contains three extra scenes that will not appear in a fresh installation.

If the interface is not in your preferred language, open File → Settings from the upper-left menu and choose a language under General → Language. Mine was already set to Traditional Chinese, so the screenshots use that interface.

The final appearance of one of my online courses. Although the brand I currently run is called Wakame, the physics brand I had used for many years was Feng-Feng, so I temporarily kept using it here. They are both my brands anyway XD.
The final appearance of one of my online courses. Although the brand I currently run is called Wakame, the physics brand I had used for many years was Feng-Feng, so I temporarily kept using it here. They are both my brands anyway XD.

We call the complete screen a scene. In the final online-course layout above, the upper-right area is the Video Capture Device, while the main area on the left is the Display Capture. The rest includes the logo, a small message, the lesson title, and a background board featuring a cat beneath a lotus leaf. The purpose of the setup is to tell OBS where each piece of content comes from and where it should appear. Those inputs are managed under Sources.

The image is labeled according to the description above. The different photos are all the same person—just with or without makeup XD.
The image is labeled according to the description above. The different photos are all the same person—just with or without makeup XD.
The Sources panel in OBS.
The Sources panel in OBS.

First, we capture the computer display for the main teaching area in the upper left. Open the PowerPoint file you want to show, click the “+” button in the lower-left corner of the Sources panel, and choose Display Capture.

A quick note about my hardware: I use two monitors. With only one monitor, it is harder to watch the OBS recording preview and the PowerPoint used for teaching at the same time. If you seriously want to create online courses, a dual-monitor setup is a wonderful working environment. Later, I even answered students’ questions while playing games on the side. Delightful!

Clicking “+” in the Sources panel opens the list of available source types.
Clicking “+” in the Sources panel opens the list of available source types.
You can enter a recognizable name for the source here, which makes it easier to identify later.
You can enter a recognizable name for the source here, which makes it easier to identify later.
Because Display Capture is recording the primary monitor while OBS is open on that same monitor, the preview creates an endless hall-of-mirrors effect. This is normal—do not worry XD.
Because Display Capture is recording the primary monitor while OBS is open on that same monitor, the preview creates an endless hall-of-mirrors effect. This is normal—do not worry XD.

My habit is to use the main monitor to watch the recording preview and quality, while the second monitor displays the lesson content. The full-screen PowerPoint therefore appears on Display 2. The camera used for Video Capture is also mounted above the second monitor, so I look as though I am watching the lesson screen while teaching. I borrowed this camera angle from the streamer Section. If you prefer to look directly at students, place the camera in front of you—or simply choose the angle you like.

Why use Display Capture rather than Window Capture? My target result was a clean PowerPoint image without the application frame, toolbar, or other window elements. In my setup, Window Capture could not reproduce the full-screen PowerPoint result shown earlier, even when the slide show itself was running full screen.

Here, the PowerPoint on the right is already full screen, but the OBS recording preview on the left still captures the complete application window. (Please ignore my chaotic desktop...)
Here, the PowerPoint on the right is already full screen, but the OBS recording preview on the left still captures the complete application window. (Please ignore my chaotic desktop...)
Using Display Capture produces the result I wanted. The image above shows the finished capture.
Using Display Capture produces the result I wanted. The image above shows the finished capture.

Next, we capture the camera. Once again, go to Sources, choose Video Capture Device, give the new source a recognizable name, and confirm. If the camera is working correctly, you should be able to select it under Device and see yourself in the preview. If no image appears, check whether there is a hardware or software problem :D.

I used a Logitech C922, so that is the device selected here. If everything works, your camera image will appear in OBS.
I used a Logitech C922, so that is the device selected here. If everything works, your camera image will appear in OBS.

After confirming, the OBS scene contains two sources: the computer display and the camera. You can freely move and resize either one with the mouse. For many streamers, this is almost enough; they may capture a game console through a capture card, another computer window, and perhaps a chat panel. I may write a separate article about streaming setups later.

The result after both sources were configured successfully.
The result after both sources were configured successfully.

But this still was not enough. I also wanted a cute logo, a cat-themed background board, the progress of each lesson, and a little message (I was very committed to the little message!). I therefore designed a background board in Illustrator. Because the planned video output was 1920×1080, I created the artwork at that size, reserved areas for the PowerPoint and camera windows, and exported it as a PNG.

The background board I regularly used for online courses, saved and exported as a PNG.
The background board I regularly used for online courses, saved and exported as a PNG.

To insert the background board, click “+” under Sources and choose Image. Select the path to the background-board file and confirm.

Selecting the background-board file path in the image-source settings.
Selecting the background-board file path in the image-source settings.
The result after inserting the image. If the size does not fit, resize it until it matches the scene canvas.
The result after inserting the image. If the size does not fit, resize it until it matches the scene canvas.

After inserting the image, you may find that the original display and camera captures have disappeared. This is a layer-order problem. Because the image was the newest source, it sits at the top and covers everything below it. Move Display Capture and Video Capture above the image, then resize them to fit the spaces reserved on the board.

The result after adjusting the layers. It now matches the intended final layout.
The result after adjusting the layers. It now matches the intended final layout.

The little message and course progress are also inserted as sources. Click “+” in Sources, choose Text, and enter the desired content in the text properties window. You can also adjust the font, alignment, and other settings. Insert the text, resize it, and move it into position—and you are done! The course-progress text works the same way.

The properties window used to insert a text source.
The properties window used to insert a text source.
The final result after the text settings were completed. It looks wonderfully polished.
The final result after the text settings were completed. It looks wonderfully polished.

You may wonder why I did not simply place the little message and course progress directly on the background board. Even a relatively lazy teacher like me, who teaches only high-school physics XD, still has three grade levels following different schedules each week. The little messages also change with the students in each class. If all of that were baked into the board, I would have to reopen Illustrator, edit the artwork, and export it again for every class. Editing the text directly in OBS is much faster and more convenient.

Audio Sources and Audio Filters in OBS

Next comes one of the most important issues: audio quality. My MSI laptop already had a built-in microphone, and the external camera could record sound as well. However, because students cared about the quality of the lesson audio, I bought a HyperX QuadCast condenser microphone. It had attractive RGB lighting (the important part!), but more importantly, it included a pop filter. I sometimes get overexcited while teaching =口= and become too loud, so that feature was essential.

OBS therefore needed to record from that specific microphone rather than the laptop or camera microphone. Open File → Settings from the top menu and configure it in the Audio panel.

The Audio settings panel.
The Audio settings panel.

Under Global Audio Devices, select the desired microphone for Mic/Auxiliary Audio. I did not need to record computer audio during my lessons, so I disabled Desktop Audio; this prevented accidental system sounds—such as input-method beeps—from entering the recording =口=. If you need desktop audio, enable it and select the appropriate computer speakers or output device.

After the setup is complete, check the Mic meter in the Audio Mixer next to the Sources panel. If you have several microphones, make sure OBS is receiving the intended device rather than another one. Speak the way you normally teach while testing. I recommend keeping the meter mostly in the green or yellow range. Reaching the red area can indicate clipping, which is unpleasant for viewers and may force them to keep adjusting the volume.

Movement in the level meter confirms that the microphone is receiving audio.
Movement in the level meter confirms that the microphone is receiving audio.

To configure microphone filters, click the small gear beside the volume meter and choose Filters. In the Filters window, click “+” at the lower left and add whatever processing you need. I usually use Noise Suppression and a Limiter: the former reduces mild background noise, while the latter limits audio peaks and lowers the risk of clipping or distortion. Adjust these according to your own needs.

Where to configure audio filters.
Where to configure audio filters.

Video Settings for Recording Online Courses with OBS

Video settings depend heavily on computer performance. Your machine must handle OBS, PowerPoint, the audio device, drawing tablet, camera, and perhaps webpages or video playback at the same time. I recommend recording several short tests before the real lesson, then checking image quality and stuttering before deciding how to adjust the settings. These choices also affect file size and YouTube upload time, so weigh them according to your needs.

Video-related settings are adjusted under File → Settings, mainly in the Video and Output sections. The values shown here worked acceptably in my tests, and my students did not complain too much XDDD. They may not be appropriate for a different task, such as recording fast-moving game footage.

My students requested uploads at 1920×1080, so I did not have much choice there XD. FPS is the frame rate—the number of frames shown per unit of time—and affects whether motion looks choppy or blurred. Our online courses mainly showed PowerPoint or camera footage, with much less motion than a game. In my tests, 30 FPS was acceptable and manageable for the computer while recording.

The video settings used for my online courses.
The video settings used for my online courses.

Under Output, switch to the advanced output mode. Because we are recording rather than broadcasting live, configure the Recording tab instead of Streaming. The recording path determines where files are saved. Choose a drive with plenty of free space so the recording does not stop halfway and force you to start over... (Yes, this happened to me.) Recording to MKV and remuxing afterward can reduce this risk. I had many lessons to upload immediately, so I recorded directly to MP4—and created that earlier tragedy for myself (sob).

For the encoder, a newer graphics card may provide hardware encoding and noticeably reduce stuttering. My graphics card was too old to support OBS hardware encoding, so I cannot personally tell you exactly how dramatic the improvement would have been...

The most important requirement for a lesson recording is avoiding lag while writing or playing PowerPoint animations, while still leaving enough CPU capacity to prevent the computer from crashing. I used the veryfast CPU preset, which uses relatively less CPU. Adjust this according to your own computer. I did not research this setting especially deeply; I tested until I found a combination that looked acceptable, produced a reasonable file size, and roughly matched recommendations I found online.

My online-course output settings, included here for reference.
My online-course output settings, included here for reference.

Starting the Online Course Recording

Once all the settings are ready, click Start Recording on the far right to begin recording the lesson!

The screen elements that deserve special attention while recording.
The screen elements that deserve special attention while recording.

The REC indicator below shows how long the recording has been running and reminds you when it might be time for a break XDDDD. Pay particular attention to CPU usage. If it gets too high, the computer may stutter badly or even crash. If that happens, adjust the recording parameters and lower CPU usage while preserving as much image quality as possible.

Conclusion

After moving from oCam to OBS, I spent nearly half a year creating online courses, and OBS remained my favorite tool. Scene setup is intuitive and convenient, and the software also works with Twitch and YouTube streaming, which explains why it is so popular among streamers. The blank interface can feel bewildering the first time you open it, but I hope this guide helps you gradually become comfortable with this excellent streaming and course-recording tool.

Online courses do not demand an elaborate OBS setup. Even without a custom background board, simply combining a camera source with a computer display can produce a polished lesson video. PowerPoint also removes the initial cost of needing a classroom and whiteboard. In my experience, the truly time-consuming work is creating slides and developing teaching materials, while the expensive part is buying the camera and microphone XD. By comparison, learning OBS is easier and free. The value for money is excellent!