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Node-script to extract GPS coordinates from QuickTime video
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| // Quite crude, but worked for the one example file I had | |
| // QuickTime docs https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFPreface/qtffPreface.html | |
| const fs = require('fs'); | |
| if (!process.argv[2]) { | |
| console.error('Please specify a file name'); | |
| process.exit(1); | |
| } | |
| const fileName = process.argv[2]; | |
| if (!fileName.match(/\.mov$/i)) { | |
| console.error('Only works with .mov files'); | |
| process.exit(1); | |
| } | |
| const file = fs.readFileSync(fileName); | |
| function getAtom(file, start) { | |
| if (start + 8 >= file.length || start < 0) { | |
| return null; | |
| } | |
| const size = file.readInt32BE(start); | |
| return { | |
| size, | |
| type: file.toString('ascii', start + 4, start + 8), | |
| start, | |
| }; | |
| } | |
| function readKeys(file, atom) { | |
| const keys = []; | |
| let offset = atom.start + 8 + 4; // skip version and flags | |
| const count = file.readInt32BE(offset); | |
| offset += 4; | |
| for (let i = 0; i < count; ++i) { | |
| const keySize = file.readInt32BE(offset); | |
| const namespace = file.toString('ascii', offset + 4, offset + 8); | |
| const value = file.toString('ascii', offset + 8, offset + keySize); | |
| offset += keySize; | |
| keys.push(value); | |
| } | |
| return keys; | |
| } | |
| function parseCoords(file, atom) { | |
| if (atom) { | |
| const value = file | |
| .toString('ascii', atom.start + 8, atom.start + atom.size) | |
| .replace(/\/$/, ''); | |
| const coord = value.split('+').slice(1); | |
| return { lat: coord[0], long: coord[1], alt: coord[2] }; | |
| } | |
| return null; | |
| } | |
| function getCoordsFromILST(file, atom, index) { | |
| let offset = atom.start + 8 + 4; | |
| const count = file.readInt32BE(offset); | |
| const items = getAtoms(file, offset + 4); | |
| return parseCoords(file, items[index]); | |
| } | |
| const coord = []; | |
| function getAtoms(file, start) { | |
| let atom; | |
| let offset = start; | |
| const atoms = []; | |
| let keys; | |
| do { | |
| atom = getAtom(file, offset); | |
| if (atom) { | |
| if (atom.type.match(/(moov|meta|trak)/)) { | |
| atom.children = getAtoms(file, offset + 8); | |
| } | |
| if (atom.type === 'keys') { | |
| keys = readKeys(file, atom); | |
| } | |
| if (atom.type === 'ilst' && keys) { | |
| coord.push( | |
| getCoordsFromILST( | |
| file, | |
| atom, | |
| keys.indexOf('com.apple.quicktime.location.ISO6709') | |
| ) | |
| ); | |
| } | |
| offset = offset + atom.size; | |
| atoms.push(atom); | |
| } | |
| } while (atom && atom.size); | |
| return atoms; | |
| } | |
| getAtoms(file, 0); | |
| console.log(coord); |
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