Look into ffmpeg’s “concat” feature. It can do what you want. https://trac.ffmpeg.org/wiki/Concatenate

Not OP, but I’ve been looking for something like this. I’ve got a couple of refrigerators and a deep freeze I’d like to monitor. I’m not looking for a cooking tool that constantly sends updates. For that I’d like to use a multi-probe Bluetooth device. I’ve got Zigbee for other sensors, and I’d like to add these to the net