I've found no easy way to do this yet, but I haven't had a lot of time to put into it. As for getting all the 5-second file segments, a really easy way to do it is with
Streaming Video Recorder (apowersoft), but it can't join the files. I've explained this challenge to their support and they say they're working on it and it will be in the next version.
VLC can play the entire folder of these crystal clear files, but there's a short pause at the end of each segment before the following one plays. Perhaps VLC has a way of exporting the playing of this sequential playlist to a file(?).