Overlay karting lap and position info on top of a video using the ffmpeg drawtext pipeline. Use either the CLI or the bundled web UI.

brew install ffmpeg

Node 18+ is recommended.

npm install

npm run web

Then open http://localhost:3000 and walk through the steps:

1. Upload video – select one or more MP4s in order (streamed to disk, 4GB+ ok).
2. Set offsets – scrub the preview and mark the start frame.
3. Lap data – paste laps, pick format/driver (TeamSport), save.
4. Preview – auto-generates a single-frame overlay just after your start; tweak text/box colors.
5. Transform & download – queue the render, poll status, and download the overlaid MP4.

The web UI always uses the ffmpeg renderer.

• Uploads and rendered/previews saved under work/ are pruned automatically (renders/uploads after ~24h, previews after ~6h). Copy anything you want to keep somewhere else.

npm run lap-timer -- \
  --inputVideo "work/video.mp4" \
  --inputLapTimes work/times.txt \
  --lapFormat daytona \
  --startTimestamp 00:12:53.221 \
  --outputFile work/out.mp4

• --startFrame can be used instead of --startTimestamp (frame index).
• --lapFormat teamsport needs --driverName "Your Name" to select the right column from the table export.
• You can concatenate multiple sources in order with repeated --inputVideo flags (e.g. --inputVideo a.mp4 --inputVideo b.mp4).
• Overlay is ffmpeg-only in the web UI and CLI to keep the flow simple.

• Run type checks before handing back work: npm run type-check.

## mac local dev env.
colima start --arch x86_64

## build
docker build --platform=linux/amd64 -t lap-timer .

## debug
docker run -it --rm lap-timer sh

## run locally from the root of the repo on http://localhost:3008
docker run -it --rm \
  -p 3008:3000 \
  -v $(pwd)/work:/work \
  --name lap-timer \
  jonnyreeves83/lap-timer:latest

## tag
docker tag lap-timer jonnyreeves83/lap-timer:latest

## publish
docker push jonnyreeves83/lap-timer:latest