GPMF extract

Finds the metadata track in GoPro (Hero5 and later) video files (or any other camera that implements GPMF) and extracts it for later analysis and processing.

Accepts a File and returns a Promise that resolves to an object with a Buffer (rawData) and timing data (timing), useful for interpreting the data.

Once extracted, you can process the data with gopro-telemetry.

Install:

$ npm i gpmf-extract

Use:

const gpmfExtract = require('gpmf-extract');
gpmfExtract(file).then(res => {
  console.log('Length of data received:', res.rawData.length);
  console.log('Framerate of data received:', 1 / res.timing.frameDuration);
  // Do what you want with the data
});

If using it in the browser, you must specify it in the second argument. Optionally, you can also pass a second argument with a function to run when the processed percentage updates.

const gpmfExtract = require('gpmf-extract');
const progress = percent => console.log(`${percent}% processed`);
gpmfExtract(file, true, progress).then(res => {
  // Do what you want with the data
});

This code was created for the GoPro Telemetry Extractor.

Here's a playlist with cool uses of the GoPro metadata .

This project is possible thanks to the gpmf-parser documentation, open sourced by GoPro.

More creative coding

If you liked this you might like some of my app prototyping.

Contribution

Please make your changes to the dev branch, so that automated tests can be run before merging to master. Also, if possible, provide tests for new functionality.

To-DO

• Unduplicate code from readBlock and readBlockWorker
• Increase browser compatibility
• Ideas for handling large files in Node?
  • (maybe trimming the video in chunks multiple of 1.001Hz) gopro/gpmf-parser#37
  • Using streams didn't work so far: gpac/mp4box.js#181
• Extract from .mov?