If you have the rear camera installed in your Thinkware dashcam, the 2 video data are stored together in 1 .avi file, which is a pain to view and share. Some video players can only view 1 video stream. VLC opens additional Direct3D Output windows all over the place. Thinkware's software is useless for this. Score another black mark against Thinkware since other brands' software have easy ways to split/export videos.
I've found a solution!
Using ffmpeg, the magic words are:
ffmpeg -i test.avi -map 0:0 -vcodec copy output1.avi