Hello,
Thanks to some persons on the Windsurfing33 french forum (Manuel Pasquiers, tnerual & Krank), We've just performed to embed speed and angle GPS data in a windsurfing video.
you can watch the video here :
This is done with GpsarPro 2.7 which generates a .srt file from one or several tracks. A .srt file is a sub-title standard format which can be used by video readers. At the moment, the information is speed and angle to wind. In case of several tracks, tracks names are added.