A Hack I Used to Skip Class

Like most people, the pandemic was a formative time for me.

It made me reconsider what I actually wanted to do with my time—and I realized that sitting through Zoom lectures wasn’t always at the top of that list.

But there was one problem: my professors required cameras to be on.

So I got to work building a fake webcam.

Step 1: Creating a Fake Webcam

Zoom doesn’t verify whether your camera is “real.” It just trusts that your operating system gives it a legitimate video feed. So if you can create a virtual video device and send a video to it, Zoom will treat it as a real webcam.

Thankfully, someone already wrote a Linux kernel module for this:

👉 v4l2loopback

This module creates virtual video devices, which is exactly what I needed.

Setting It Up

First, clone the repo and install the kernel module:

make && sudo make install
sudo depmod -a

Then, load the module:

sudo modprobe v4l2loopback

Once this is done, you should see a new video device on your machine—for me, it was /dev/video2.

Step 2: Feed It a Fake Video

Now that I had a virtual webcam, I needed to feed it a video file. Enter FFmpeg, the Swiss Army knife of video tools.

I wrote a simple shell script to stream a video file to my virtual webcam:

#!/bin/sh

echo "Spoofing camera with $1"
ffmpeg -re -stream_loop -1 -i "$1" \
  -vf "scale=1280:720,fps=30,format=yuv420p" \
  -pix_fmt yuv420p \
  -f v4l2 /dev/video2

This sends a looping, real-time video stream to the fake webcam. After testing it on Zoom with some stock footage, it worked like a charm.

Step 3: Using It

To make it believable, I recorded a 10-minute clip of myself watching a YouTube video—expressionless, occasionally blinking, just like in real class.

Before each session, I’d throw on the same generic gray shirt I wore in the video. I'd join class with my real camera, wait until roll call or instructions were done, then switch my Zoom input to the virtual camera.

And just like that I automated zoom class.

After my first success, I figured that there might be classes where I may need to appear like I am working instead of blankly staring. So I made another recording of pretending to be diligently writing things down.

Conclusion

This hack was a fun to pull off, I certainly used it bit while I was in college. Luckily, no one ever asked why I wore the same shirt in every class.

But more than anything, it reminded me that hacking—whether it’s software, systems, or daily life—is a great way to stay curious and keep learning.

And that’s priceless.