Vakaros video overlay — your race data on your sailing footage
Drop in a Vakaros Atlas VKX file and your onboard video, and Sail Smarter lines them up and plays the race back with the instrument data drawn over the picture — speed, VMG, heading, heel, and, through the start, time to the gun and distance to the line. It runs in your browser: nothing to install, and the video is never uploaded.
Free to use.
How it works
Four steps, and the longest of them is choosing the files.
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Drop in the race file
The .vkx straight off your Atlas. No CSV export step — the file is read as it comes off the instrument, and Velocitek .vtk files work too.
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Add your footage
.mp4 or .mov from a GoPro, DJI, Insta360 or a phone, or a GoPro .lrv proxy. Multi-part recordings join into one clip.
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It syncs itself
From the timestamp the camera wrote into the file. No usable timestamp, or a camera clock set to local time? Pin it to the start gun in one click instead.
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Pick a moment
The race arrives already broken into the start, each leg, every tack, gybe and mark rounding. Click one and the video jumps there with the overlay running.
What appears over the picture
Read from your own file, interpolated to the exact frame on screen — not averaged over a second, and not a rough alignment.
- SpeedSOG from GPS, and STW where the Atlas has a paddlewheel or transducer feeding it.
- VMGVelocity made good to windward, against the wind direction worked out from your own tacks.
- Heading, COG and heelCompass heading and heel come straight from the Atlas, so they are measured rather than inferred.
- Distance to the start lineSigned metres to the line as a large readout, from the pin and committee-boat positions your Atlas logged.
- Time to the gunThe countdown, plus time to burn — how long you would waste at your current closing speed.
- Favoured endWhich end is favoured and by how many metres, live through the approach.
- TWD, with Live Wind PredictionSwitch it on and the wind is read off your own straight-line sailing as it shifts, instead of one direction for the whole race. The live bearing goes on the picture as a readout and as a trace in the corner, so a header you sailed into is something you can see arrive.
It rates the manoeuvre, not just labels it
This is the part a gauge overlay can't do. Every tack, gybe and mark rounding is scored on the distance it actually cost you — measured by comparing the VMG you were making before and after the turn against what you made through it. That number is in metres, on the screen, next to the footage of the turn that produced it.
Social video export
One button on the comparison screen saves the pair as an upright video — the two clips stacked one above the other, each with its own overlay, trimmed to the part both cover. Ready to post as it comes out. Like every export here, it is composited in your browser: the footage never leaves your machine.
Where it differs from a general telemetry overlay
Tools like Telemetry Overlay put gauges on any action footage and do it well, across a lot of sports. This is narrower on purpose: it only does sailboat racing, and it starts from the race rather than from the video.
| Sail Smarter Video Overlay Analysis | A general telemetry overlay tool | |
|---|---|---|
| Where it runs | In your browser — nothing to install | Desktop application to download |
| Getting the data in | The .vkx file as it comes off the Atlas | Usually a CSV you export first |
| What it shows | Race readouts: VMG, distance to the line, time to burn, favoured end | General gauges: speed, heading, altitude, map |
| Finding a manoeuvre | Listed for you — click a tack and the video goes there | Scrub the clip and find it yourself |
| Rating a manoeuvre | Distance lost in metres, per tack, gybe and rounding | Not what it's for |
| Cost | Free | Typically a paid licence |
Sail Smarter is an independent project and is not affiliated with, endorsed by, or connected to Vakaros, Velocitek, GoPro or any overlay software vendor. If what you want is gauges on footage from any sport, a general tool is the better fit and you should use one.
Vakaros video overlay — FAQ
Can I put Vakaros data over my sailing video?
Yes. Sail Smarter Video Overlay Analysis reads a Vakaros Atlas VKX file directly — no CSV export step — lines it up with your onboard footage, and draws speed over ground, speed through water, VMG, heading, COG, heel and, during the start, time to gun and distance to the line over the picture. It runs in your browser, so there is nothing to install.
Do I have to upload my video?
No. The video is opened straight from your own disk, decoded by your browser and drawn to a canvas with the overlay on top. It is never uploaded, so there is nothing to wait for even with a 4K clip. Only the race file — a few megabytes — is sent for analysis.
What video formats does the Vakaros overlay accept?
MP4 and MOV files encoded as H.264, which is what GoPro, DJI, Insta360 and phones record by default, plus GoPro's .LRV proxy files. Multi-part GoPro recordings such as GH010001.MP4 and GH020001.MP4 can be added together and are treated as one continuous clip. HEVC/H.265 clips play in Safari and in recent Chrome on Mac and Windows but not in every browser — see the devices and file formats page.
How does the video get synced to the Vakaros track?
First from the timestamp the camera writes into the video file itself, which usually lands it within a few seconds. If the clip carries no readable timestamp, or the camera's clock was set to local time rather than UTC, you can pin it to the start gun instead — pick the frame where the gun goes and the whole race lines up from there. A nudge control adjusts it by half a second at a time during playback.
Does it work with a Velocitek instead of a Vakaros?
Yes — Velocitek VTK files work too. A Vakaros Atlas gives more: it records compass heading, heel and the start line's pin and committee-boat positions, so heading, heel and the start-line readouts come from the instrument rather than being derived or unavailable. The devices page sets out what each one records.
Is it just gauges, or does it analyse the race?
It analyses the race first, then shows the footage of it. The race file is broken into the start, each leg, every tack and gybe and every mark rounding, and each manoeuvre is rated for the distance it actually cost — measured against the VMG you were making either side of the turn. You pick a manoeuvre from that list and the video jumps to it, rather than scrubbing a two-hour clip looking for it. The same engine also runs Single Boat Analysis and Tuning Partner Analysis.
Try it with your own race
Sign in, drop in your VKX file and your footage, and pick a tack.