A capture device plugged directly into the box itself recorded on to a app of various choice would work. I use an Elgato HD capture device (yes I know it's meant for gaming) but it's really effective, easy to use and produces very high, full 1080p quality files at the end of it. You can even plug it straight into a computer with the right the cables, as long as you can bypass the signal encryption which may require a signal splitter of some sort.