Converts Shotdetect's results.xml file to CSV

shotdetect2csv.rb

#!/usr/bin/env ruby

# Extracts shotdetect's results.xml file to csv
# with relative position of shot in movie.
# Writes converted file to results.csv file.
#
# Usage: ./shotdetect2csv.rb results.xml

require "nokogiri"
require "csv"

doc = nil
File.open ARGV[0] do |f|
  doc = Nokogiri::XML f
end

msduration = doc.at_css('duration').text.to_f
nshots = doc.css('body shot').size.to_i

shots = []
doc.css('shots').children.each do |item|

  # Convert Nokogiri::XML::Attr attributes to string and back to attributes hash
  shot = Hash[item.attributes.map{ |k, v| [k.to_sym, v.to_s]} ]

  # Calculate position of shot in the whole stream
  shot[:msratio] = shot[:msbegin].to_f / msduration

  shots << shot
end

CSV.open("shots.csv", "w") do |csv|
  csv << shots.first.keys
  shots.each do |hash|
    csv << hash.values
  end
end