add speed to .gpx

[Lobotron]

Hi,

can I ask You please?
I bought gopro 6 cam and I'm looking for software for adding telemetry to video under linux
I can get .gpx from the video (with David Stillman gopro utils), I can add altitude, coordinates, course (with gpsbabel), map (with zdila gpx animator or gps-overlay-on-video-master)

- but with no speed data - I can not find anything for calculating and adding speed to .gpx :-/


can someone to help me please?

sorry for my english

Marek