Program to adjust dates on EXIF tags for a bunch of JPEG files using python-exif and exiftool

redate-photos.py

#! /usr/bin/python
"""Program to fix my screwed up camera date/time settings.

At some point, some children adjusted the date on my camera as well as
the locale settings. Photos were henceforth marked as being one day
earlier than they should have been (i.e. the 28th instead of the 29th).

Later, I noticed that the camera date was wrong, but because the
equivalent of LC_DATE was different, I thought it was one MONTH early
instead of one DAY. I "fixed" it by putting the date on the camera
one month forward.

Eventually I noticed that the date was even more wrong, put the camera
back in en-US, and quietly panicked because all of the EXIF date tags
were screwed up on my images.

This script is meant to adjust the dates on all images to accord with
what I think is the correct date.

Starting at (possibly earlier?) DSCN8367.JPG, photos are one day
behind when they should be: May 28th instead of May 29th. This
continues through DSCN8580.JPG, which is June 6th but should be June
7th. I "fixed" it by adding one month but not one day: DSCN8581.JPG
says July 9th, but should be June 10th (a difference of 29 days).
This continues through DSCN8981.JPG. DSCN8982.JPG jumps back 27 days
(presumably two days after the last photo)."""

import sys
import os
import re
import subprocess
import datetime
import EXIF

FILENAME_RE = re.compile("dscn(\\d+)\\.jpg", re.I)
EXIF_TS_FORMAT = "%Y:%m:%d %H:%M:%S"

def photo_number(fname):
    match = FILENAME_RE.match(fname)
    if not match: return None
    return int(match.group(1))

def to_exif(ts):
    return ts.strftime(EXIF_TS_FORMAT)

def from_exif(tag):
    return datetime.datetime.strptime(str(tag), EXIF_TS_FORMAT)

def adjust_date(fname, delta):
    f = open(fname, 'rb')
    tags = EXIF.process_file(f)
    #dump_tags(fname, tags)
    date = from_exif(tags['EXIF DateTimeOriginal'])
    assert date == from_exif(tags['Image DateTime'])
    assert date == from_exif(tags['EXIF DateTimeDigitized'])

    args = ['exiftool', fname]

    for tag in ['DateTimeOriginal', 'CreateDate', 'ModifyDate']:
        args.append('-{0}={1}'.format(tag, to_exif(date+delta)))

    args.append('-FileModifyDate={0}-04:00'.format(to_exif(date+delta)))

    print "{0}: {1} {2}".format(fname, date, date+delta)
    print args
    retcode = subprocess.check_call(args, executable="/usr/bin/exiftool", stdout=sys.stdout, stderr=sys.stderr)
    #print "{0}: {1}".format(fname, tags['Image Orientation'])

def dump_tags(fname, tags):
    print fname
    for tag in tags.keys():
        if tag not in ('JPEGThumbnail', 'TIFFThumbnail', 'Filename',
                       'EXIF MakerNote'):
            try:
                str(tags[tag])
            except TypeError:
                print "Couldn't stringify {0}: {1}".format(tag, tags[tag].__class__)
                continue
            print "Key: {0}, value {1}, type {2}".format(tag, tags[tag], tags[tag].__class__)

if __name__ == '__main__':
    dir = os.listdir(".")
    dir.sort()
    #dir = dir[:1]

    # Used to bump up pictures that were a day behind.
    forward_delta = datetime.timedelta(days=1)

    # Used to bump back pictures that were almost a month ahead.
    backwards_delta = datetime.timedelta(days=-29)

    for fname in dir:
        num = photo_number(fname)
        if num == None: continue # skip *-resize.jpg

        if 8367 <= num <= 8580:
            adjust_date(fname, forward_delta)
        elif 8581 <= num <= 8981:
            adjust_date(fname, backwards_delta)
        else:
            print "{0} is not in the affected range; leaving unchanged".format(fname)