GoPro Speedometer Visualizer

Generates a chroma-key-ready (green background) speedometer video from GoPro GPS telemetry data exported by gopro2gpx.

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WHY USE THIS ?

I didn't find a tool that just gives me plain old greenscreen video feed that i can key into my original video. I've built this tool on top of gopro2gpx. Gopro 2 Gpx has an overlay feature. but I found that the time taken for it to process was ~20 mins for an 8 minute video & I ran out of ram (8GB on my macbook air M3). Feel free to criticize it or add to it. I hope 1 person finds this helpful. If you are that 1 person, A Star in this repo is appreciated.

Requirements

pip install opencv-python-headless Pillow numpy

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Step 1 – Export GPS data from your GoPro footage

Use gopro2gpx to extract telemetry from your .MP4 file:

pip install git+https://github.com/juanmcasillas/gopro2gpx 
# Or Download the repository at https://github.com/juanmcasillas/gopro2gpx unpack it and install with 
python -m pip install .

# Export all three formats at once
gopro2gpx -s GH010001.MP4 output
# Produces: output.csv  output.gpx  output.kml

Tip: The .csv and .gpx outputs contain speed data. The .kml file does NOT include speed — use CSV or GPX.

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Step 2 – Generate the speedometer video

python speedometer.py output.csv -o speedometer.mp4

All options

usage: speedometer.py [-h] [-o OUTPUT] [--fps FPS] [--unit {km/h,mph}]
                      [--size SIZE] [--max-speed MAX_SPEED]
                      [--smoothing SMOOTHING]
                      input

positional arguments:
  input                 Path to gopro2gpx output (.csv, .gpx, or .kml)

options:
  -o OUTPUT             Output video path (default: <input>_speedometer.mp4)
  --fps FPS             Frames per second (default: 18 — matches GoPro GPS rate)
  --unit {km/h,mph}     Speed unit on the dial (default: km/h)
  --size SIZE           Canvas size in pixels, square (default: 400)
  --max-speed MAX_SPEED Max speed shown on dial (auto-calculated if omitted)
  --smoothing N         Rolling-average window to smooth needle (default: 3, 1=off)

Examples

# Basic usage (km/h, auto dial range)
python speedometer.py output.csv

# Miles per hour, larger overlay, custom dial max
python speedometer.py output.gpx --unit mph --size 500 --max-speed 60

# Silky smooth needle, 30fps sync
python speedometer.py output.csv --fps 30 --smoothing 5

# Full control
python speedometer.py output.csv \
  -o my_ride_speedometer.mp4 \
  --fps 60 \
  --unit km/h \
  --size 600 \
  --max-speed 120 \
  --smoothing 5

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Step 3 – Chroma key into your video editor

The output video has a pure green (#00FF00) background — compatible with:

Editor	How to apply chroma key
DaVinci Resolve	Color → Qualifier → pick green, or Fusion → ChromaMatte
Adobe Premiere	Effects → Keying → Ultra Key
Final Cut Pro	Effects → Keying → Keyer
CapCut / mobile	Overlay → Chroma Key
OBS Studio	Filters → Chroma Key

Drag the speedometer clip as an overlay track above your GoPro footage and apply the chroma key effect. Resize and reposition as needed.

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Dial appearance

Speed range	Arc colour
0 – 60 % of max	🟢 Green
60 – 85 % of max	🟡 Yellow
85 – 100 % of max	🔴 Red

The needle turns orange-red (GoPro style) and the digital readout updates every frame.

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Supported input formats

Format	Speed data	Notes
.csv	✅ speed column (m/s)	Best option
.gpx	✅ <gpxtpx:speed> extension	Works perfectly
.kml	❌ No speed embedded	Warning shown; use CSV/GPX