Do I need a GPS logger?

Not necessarily. A GoPro from the HERO5 onwards records GPS and accelerometer data inside the video file, which is enough for speed and G-force. You need a logger and a .vbo only if you want lap times and lap deltas, or if your camera has no GPS.

How long does the export take?

It depends on your machine and the resolution. Encoding happens locally, so a fast desktop renders considerably quicker than a laptop, and 4K takes noticeably longer than 1080p. TrackHero shows a file-size estimate before you commit.

Can I do this on a phone?

Not with TrackHero. It requires Chrome on a desktop computer, because the video encoding relies on browser APIs not available on mobile. Some phone apps, such as dragy·Lap, overlay on-device instead.

Will it work if my camera split the session into multiple files?

Cameras split long recordings for filesystem reasons. Load the segment that covers the laps you care about, or join the segments in a video tool first so the timeline is continuous.

Guides

How to add a telemetry overlay to track day video

To add a telemetry overlay to track-day video you need a GPS data source, your onboard footage, and a tool that renders one onto the other. Export a .vbo from RaceChrono, VBOX or Dragy, or use a GoPro from the HERO5 onwards (which stores telemetry inside the video file), then load both into TrackHero in desktop Chrome, align them on the timeline, and export an MP4. It is free and nothing is uploaded.

What you need

Three things:

A GPS data source. Either a logger that exports a .vbo, such as RaceChrono Pro, VBOX Motorsport or Dragy, or a GoPro from the HERO5 onwards, which records telemetry inside the video file itself.
Onboard video of the same session.
A tool to render one onto the other. This guide uses TrackHero, which is free and runs in a browser. The alternatives are mostly paid desktop applications.

If you shoot on a GoPro with GPS, you can skip the logger entirely, though you will not get lap times, because the camera does not know where the circuit’s start/finish line is.

Step 1: Export your data

The export path depends on your logger:

RaceChrono Pro: open the Lap times list, press Options, choose Export laps, set Type to VBox (.vbo), choose a Scope, press Start. Pick All laps rather than a single lap if you want lap deltas. There is a detailed walkthrough.
VBOX: copy the .vbo from the unit’s storage.
Dragy: export the session from the app in VBO form.
GoPro: nothing to do, provided GPS was enabled and the camera had a satellite lock.

Step 2: Load everything

Open TrackHero in desktop Chrome and drag in the .vbo and the video together. Nothing is uploaded: the files are read locally by the browser and stay on your machine.

Step 3: Sync the data to the footage

This is the step that determines whether the result looks right, and it is worth taking a minute over.

The logger and the camera started at different moments, so the data has to be shifted to line up with the picture. TrackHero shows a dual-track timeline: the video’s audio loudness on one track, the GPS speed trace on the other.

Those two curves have the same shape. Engine noise rises with speed, so the loudness peaks sit on the straights, exactly where the speed peaks do. Drag the data until the peaks land on top of each other, then use the nudge buttons to refine it. Lap bands mark where each lap begins, which makes gross misalignment obvious at a glance.

There is a dedicated guide to syncing if the alignment is being stubborn.

Step 4: Choose what appears

Every overlay element is optional and only shows when there is data behind it:

speed gauge with a needle that turns red near your session top speed;
G-force plot scaled to your own peak G;
live lap delta against your best lap, green when up and red when down;
lap overview of your last four laps, with outlap and inlap badges;
driver and session panel: name, photo, car, track, weather.

Pick an accent colour and it runs through every element.

Step 5: Export

Choose a resolution from 720p up to 4K. TrackHero caps the output at your source resolution so it never upscales, and shows a file-size estimate before you start. Render the whole session, or just a lap range if you only want your quick one.

If you have a .vbo but no footage yet, you can also export the overlay on its own as a transparent-matte pair of files, and composite it over video in an editor later.

Common problems

The gauges are empty. The data file has no samples covering that part of the video, or a GoPro recorded without a GPS lock. Check the .vbo in a text editor, or try a different clip.

Speed looks right but lap delta is missing. A delta needs more than one lap to compare against. If you exported only your best lap, re-export with All laps.

The overlay drifts out of sync over the session. Usually the camera and logger clocks run at slightly different rates. Align on the section you care about most, or render a shorter lap range.

Last updated 2026-08-28.