For Adobe Lightroom XMP files, a quickie Ruby script to timeshift the capture time by an arbitrary number of seconds

add-seconds-to-timestamp-xmp.rb

# A quickie script to timeshift all XMP files of a certain camera model
# by an arbitrary number of seconds

require 'nokogiri'
require 'chronic'
require 'fileutils'
files = Dir.glob('./xmps/*.xmp')
orgdir = "./new-xmps"
seconds_to_shift = 98
model_name_to_change = 'NEX-7'

files.each do |file|
  xstr = open(file){|f| f.read }
  # we'll just overwrite the time values in xstr rather than rebuild a XML file
  # via Nokogiri
  xmp = Nokogiri::XML(xstr)
  attrs = xmp.children[0].children[1].children[1].attributes
  model = attrs['Model']

  if model.value == model_name_to_change
    datetime = attrs['DateTimeOriginal']
    prevtime = datetime.value
    t = Chronic.parse(prevtime)
    newtime = (t - seconds_to_shift).strftime("%Y-%m-%dT%H:%M:%S")
    open(File.join(orgdir, File.basename(file) ), 'wb'){|o| o.write xstr.gsub(prevtime, newtime) }
  end
end