Rospilot (https://github.com/rospilot/rospilot) is an open-source companion computer for the APM that handles higher level functionality, like running an on-board Wifi access point, providing a web interface, and live H264 recording and streaming. It runs on any single-board computer (tested with the Odroid series, shown), and connects to the APM via USB.

It's based on well known libraries as much as possible and uses ROS for the core communication and process management, runs on Linux, and is written in Python and C++. The video transcoding is done with ffmpeg (or the hardware encoder on Exynos4 based boards) and is streamed as H264 to the browser. In my field testing, I've regularly been able to get latency down to 100-200ms with very low bandwidth.

As long as you have a Wifi adapter that can host an access point, it will create a Wifi network via hostapd, which allows the web interface to be accessed from any device - even a smartphone!

Would love feedback on Rospilot, and if you've building something similar let me know!