SirenGPX Speed & heart-rate overlay for your ride videos

The SirenGPX app overlays your speed, heart rate and route — from Apple Health or a GPX file — onto your ride videos, rendered right on your phone.

What it does

Turn ride data into video

⌚

Apple Health

Pull workouts straight from Apple Health — no third-party account needed. Works with Apple Watch, Garmin, Wahoo and anything that saves workouts to Health.

🗂️

GPX import

Not using Apple Health? Import a .gpx file from any GPS device or bike computer — speed and route work the same way.

✨

Magic Sync

No manual alignment needed. The app automatically syncs your video with the workout based on timestamps.

📱

On-device rendering

FFmpeg burns the overlay into your video locally. Your footage never leaves your phone.

⚡

9 speedometer styles

From minimal to bold, or drawn in your frame’s look — then drag it wherever you want it in the frame.

🗺️

13 templates

From a minimal bike computer to full-screen looks — Cyber Rider, VHS Tape, Grand Tour, Aurelia, APEX, Meridian and more. Or build your own Custom frame.

📊

Rich metrics

Heart rate, altitude, distance, ride time, max speed, gradient, cadence, power, temperature and calories — plus a route map, an elevation profile and a title.

🔒

Secure & Private

Read-only access to Apple Health. Your workout data and videos never leave the device — no accounts, no cloud, no uploads.

Real app

See it in action

SirenGPX matching a video from Photos to a workout
Your video is auto-matched to the right workout.
SirenGPX studio: live preview of the frame and the template list
Tune the speedometer, metrics and layout in the studio.
How it works

Four steps to a finished clip

1

Connect a data source

Grant read-only access to Apple Health to pull your workouts automatically, or import a .gpx file manually — no wearable required.

2

Pick a video

Choose a clip from Photos — the matching workout is found for you.

3

Customize the overlay

Pick a template, or build your own frame: drag the speedometer, sensors and map where you want them.

4

Create & save

FFmpeg renders the video on your phone and saves it straight to Photos.

Data

What you can overlay

MetricApple HealthGPX file
Speed & distance✓ GPS workouts✓ from track points
Heart rate✓ watch or strapif your device recorded it
Altitude, gradient, map✓ with GPS route✓ from track points
Cadence & powerwith sensors (iOS 17+)cadence, if recorded
Calories✓—
Temperature—if your device recorded it

Works with any outdoor GPS workout — cycling, running, hiking, skiing. Indoor workouts without GPS can’t provide speed or a route. Not using Apple Health? Import a .gpx file from any GPS device or bike computer instead.

Pricing

Simple & transparent

Free

$0 / forever
  • 6 speedometer styles
  • Basic metrics (HR, Distance, Altitude, Ride time, Max speed, Temperature, Calories, Map, Elevation profile)
  • 12 of 13 templates, incl. Cyber Rider, VHS Tape, Grand Tour, Aurelia, APEX, Meridian
  • Custom frame with 3 looks: Neutral, VHS Tape, Superlight
  • Magic Sync & On-device rendering
  • Includes a small watermark
  • Pro metrics (Power, Gradient, Cadence)
  • Pixel Racer theme

Pro

$4.99 / one-time
  • All 9 speedometer styles
  • All metrics (Power, Gradient, Cadence)
  • Pixel Racer theme · exclusive
  • All 13 looks for your Custom frame
  • No watermark on exports
  • One-time purchase, yours forever
FAQ

Frequently asked questions

Which cameras and video formats are supported?

Any video in your phone’s Photos library — footage from the phone itself, GoPro, DJI or any action camera, once it’s imported to Photos. The overlay is matched by the time the video was filmed, so make sure your camera’s clock is set correctly.

How does syncing work? Do I need to align anything manually?

No. The app reads the video’s creation time and finds the Apple Health workout — or GPX track — that was running at that moment. Speed and metrics are aligned to the second automatically.

Are my videos uploaded anywhere?

Never. Rendering runs entirely on your phone with FFmpeg. No accounts, no cloud, no uploads — see the Privacy Policy.

Why is a metric greyed out?

That workout simply doesn’t contain it: power and cadence need sensors, heart rate needs a watch or strap, the map and altitude need a GPS track, temperature needs a thermo sensor.

Is Pro a subscription?

No. Pro is a one-time purchase — pay once, keep it forever. Refunds are handled by the App Store under its standard policy.

Your data stays yours

No accounts, no servers, no uploads. Apple Health data and your videos never leave the device. Read the full Privacy Policy.