Golang: Read creation time from mov/mp4

movmeta

package main

import (
	"bytes"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"os"
	"time"
)

// mov spec: https://developer.apple.com/standards/qtff-2001.pdf
// Page 31-33 contain information used in this file

const appleEpochAdjustment = 2082844800

const (
	movieResourceAtomType   = "moov"
	movieHeaderAtomType     = "mvhd"
	referenceMovieAtomType  = "rmra"
	compressedMovieAtomType = "cmov"
)

func getVideoCreationTimeMetadata(videoBuffer io.ReadSeeker) (time.Time, error) {
	buf := make([]byte, 8)

	// Traverse videoBuffer to find movieResourceAtom
	for {
		// bytes 1-4 is atom size, 5-8 is type
		// Read atom
		if _, err := videoBuffer.Read(buf); err != nil {
			return time.Time{}, err
		}

		if bytes.Equal(buf[4:8], []byte(movieResourceAtomType)) {
			break // found it!
		}
		
		atomSize := binary.BigEndian.Uint32(buf) // check size of atom
		videoBuffer.Seek(int64(atomSize)-8, 1)   // jump over data and set seeker at beginning of next atom
	}

	// read next atom
	if _, err := videoBuffer.Read(buf); err != nil {
		return time.Time{}, err
	}

	atomType := string(buf[4:8]) // skip size and read type
	switch atomType {
	case movieHeaderAtomType:
		// read next atom
		if _, err := videoBuffer.Read(buf); err != nil {
			return time.Time{}, err
		}

		// byte 1 is version, byte 2-4 is flags, 5-8 Creation time
		appleEpoch := int64(binary.BigEndian.Uint32(buf[4:])) // Read creation time

		return time.Unix(appleEpoch-appleEpochAdjustment, 0).Local(), nil
	case compressedMovieAtomType:
		return time.Time{}, errors.New("Compressed video")
	case referenceMovieAtomType:
		return time.Time{}, errors.New("Reference video")
	default:
		return time.Time{}, errors.New("Did not find movie header atom (mvhd)")
	}
}

func main() {
	fd, err := os.Open(os.Args[1])
	defer fd.Close()

	created, err := getVideoCreationTimeMetadata(fd)
	if err != nil {
		fmt.Println(err.Error())
		return
	}

	fmt.Printf("Movie created at (%s)\n", created)
}

@phelian nice research, kinda crazy how MP4 and MOV both share the same algorithm to extract date created.

I just uploaded a repo where I copied your code:

https://github.com/davidrenne/mediaRenamerToTimestamp

I am a huge dropbox fan of how they sync multiple phone files and digital camera cards and rename to this format. But I wanted my own way to rename files so I wrote this out of necessity to clean up some of my media collection of family photos.