Offline Video with Speed and Splits

Benedikt, February 8 2023

In hotels, there is not always a superfast internet connection available for interactive video analysis via our web app. For these situations we have released a small app which will overlay the speed data locally, without the need of uploading any video to our platform. And our app can even add split times from "traditional" photo-cells.

The app was developed with the precious support of the German men's alpine speed team who use this app daily. Thank you for providing all the data and videos necessary for the development and the countless emails, WhatsApp messages and phone calls exchanged over the last weeks to make sure we make a usable and valid tool.

How does it work?

3 steps during the training

  1. Each athlete wears one Naos sensor, which records 3D acceleration, rotation, speed and position over 200 times per second. This data is either transmitted live to our webapp (online mode) or via USB at the end of the training (offline mode).
  2. Film the athletes as usual. Our video sync unit is plugged into the camera's microphone input and ensures that we can automatically compute the exact time of each video frame.
  3. Use a Microgate timing system with GPS-support to measure the split times.
Photo of a training session in Zermatt

3 steps after the training

  1. Copy all the videos in one folder and export the splits from the Microgate timing system in the Excel format to the same folder.
  2. On the webapp, assign the sensor data to the athletes and use the smart segmentation to automatically detect all runs.
  3. Run the local app. Go eat lunch or have a coffee while waiting for the video processing to be finished.

While you eat, the local app will find the exact start times of each video. It will query the webapp for data recorded at the same time as the video. The webapp will identify the correct athlete and run, and return the corresponding 3D position and speed data. Even though there are over 1000 datapoints per second to transmit, a bad internet connection suffices and all data is received by the local app within a few seconds. It reads this data, identifies for the corresponding splits in the Microgate Excel file and creates the overlay.

Remember: all this is fully automatic and runs in the background. No user interaction is needed.

Video Analysis

The local app creates standard MP4 video files containing the overlay. They can be played and compared side-by-side with any video player such as for example Kinovea. With the videos you can compare how different lines and athlete movements influence the skiing speed and what effect they have on the time. It has never been so easy to find out the fastest line and teach an athlete how his/her movement changes the skiing speed.

The app is immediately available to all existing customers. Not yet a customer? Contact us to get a quote for a complete system.