Preface

Rather than having a second monitor connected to my laptop, I use 2 laptops simultaneously. The problem with this is if there is audio playing from both computers, it must be "down mixed" to play on, for instance, 1 pair of Bluetooth headphones.

This is a little driver I wrote as a Bash script to do just that. Of course, both computers are connected to the same LAN so initially it simply piped unencrypted audio using BSD's netcat tool, however later I made and tested a proof of concept that uses the SSH protocol encrypted over the internet to send live audio from one computer to another.

The result is I can now work on video editing on the main laptop while watching YouTube on the second laptop, and hear both at the same time in headphones connected to only the main laptop. In reality, there are countless uses for mixing down audio from two devices simultaneously.

Technologies

• PipeWire: a modern userland (ring 2) Linux audio driver replacing PulseAudio in most modern Linux distributions (however any other audio driver can be used in its place)

• netcat: an ancient but still useful simple tool for transferring text over TCP/UDP (used for local low-latency unencrypted transmission over LAN)

• SSH: an OpenBSD protocol primarily for secure remote management (personally my favorite protocol to transfer any kind of data/files/audio/commands/internet proxy/VPN)

Source Code

Let's see it in action