Getting metadata for MOV video

问题:

I' ve a .MOV video sent by a phone messanger app. Can I retrieve the real creation data of the file and the author? I tried with ffprobe, mediainfo and similar tool but give me only the date when I download it.

回答1:

I wrote a quick Python script that can obtain the creation and modification timestamps, since those are easy to find. Finding the author is a bit harder because it can be stored in several different ways. Example usage:

$ ./mov-timestamps.py file.mov
creation date: 2013-03-29 16:14:01
modification date: 2013-03-29 16:14:13

Sometimes you might see a date of 1/1/1904. That means the timestamp is 0. If you see a date of 1/1/1970, the file was probably generated by FFmpeg, which doesn't store this metadata for security reasons.

#!/usr/bin/python

import datetime
import struct
import sys

ATOM_HEADER_SIZE = 8
# difference between Unix epoch and QuickTime epoch, in seconds
EPOCH_ADJUSTER = 2082844800

if len(sys.argv) < 2:
    print "USAGE: mov-length.py <file.mov>"
    sys.exit(1)

# open file and search for moov item
f = open(sys.argv[1], "rb")
while 1:
    atom_header = f.read(ATOM_HEADER_SIZE)
    if atom_header[4:8] == 'moov':
        break
    else:
        atom_size = struct.unpack(">I", atom_header[0:4])[0]
        f.seek(atom_size - 8, 1)

# found 'moov', look for 'mvhd' and timestamps
atom_header = f.read(ATOM_HEADER_SIZE)
if atom_header[4:8] == 'cmov':
    print "moov atom is compressed"
elif atom_header[4:8] != 'mvhd':
    print "expected to find 'mvhd' header"
else:
    f.seek(4, 1)
    creation_date = struct.unpack(">I", f.read(4))[0]
    modification_date = struct.unpack(">I", f.read(4))[0]
    print "creation date:",
    print datetime.datetime.utcfromtimestamp(creation_date - EPOCH_ADJUSTER)
    print "modification date:",
    print datetime.datetime.utcfromtimestamp(modification_date - EPOCH_ADJUSTER)

回答2:

So, I updated MMM's code to Python3 and improved a few things.

def get_mov_timestamps(filename):
    ''' Get the creation and modification date-time from .mov metadata.

        Returns None if a value is not available.
    '''
    from datetime import datetime as DateTime
    import struct

    ATOM_HEADER_SIZE = 8
    # difference between Unix epoch and QuickTime epoch, in seconds
    EPOCH_ADJUSTER = 2082844800

    creation_time = modification_time = None

    # search for moov item
    with open(filename, "rb") as f:
        while True:
            atom_header = f.read(ATOM_HEADER_SIZE)
            #~ print('atom header:', atom_header)  # debug purposes
            if atom_header[4:8] == b'moov':
                break  # found
            else:
                atom_size = struct.unpack('>I', atom_header[0:4])[0]
                f.seek(atom_size - 8, 1)

        # found 'moov', look for 'mvhd' and timestamps
        atom_header = f.read(ATOM_HEADER_SIZE)
        if atom_header[4:8] == b'cmov':
            raise RuntimeError('moov atom is compressed')
        elif atom_header[4:8] != b'mvhd':
            raise RuntimeError('expected to find "mvhd" header.')
        else:
            f.seek(4, 1)
            creation_time = struct.unpack('>I', f.read(4))[0] - EPOCH_ADJUSTER
            creation_time = DateTime.fromtimestamp(creation_time)
            if creation_time.year < 1990:  # invalid or censored data
                creation_time = None

            modification_time = struct.unpack('>I', f.read(4))[0] - EPOCH_ADJUSTER
            modification_time = DateTime.fromtimestamp(modification_time)
            if modification_time.year < 1990:  # invalid or censored data
                modification_time = None

    return creation_time, modification_time

and...

Wouldn't you know it, just as I finished I found how to do it with exiftool, which I use for similar tasks with .jpg files. :-/

⏵ exiftool -time:all img_3904.mov