rorate.rb

#!/usr/bin/env ruby
# Rotate video files.
require 'shellwords'
require 'colorize'

TMPFILE = "/tmp/ffprobe_out.txt"
IMAGES = ["mjpeg", "jpg", "jpeg", "png", "gif"]

if (`which ffmpeg` == "")
  puts "You need ffmpeg to use this command."
  exit 1
end

def detect(file)
  system("ffprobe -v info #{file.shellescape} > #{TMPFILE} 2>&1")
  output = open(TMPFILE).read
  vregex = /Stream .+? Video: (\w+)/
  vmatch = vregex.match(output)
  vcodec = vmatch[1] unless vmatch.nil?
  aregex = /Stream .+? Audio: (\w+)/
  amatch = aregex.match(output)
  acodec = amatch[1] unless amatch.nil?
  File.unlink TMPFILE
  return [acodec, vcodec]
end

def is_video(file)
  vcodec = detect(file)[1]
  return false if vcodec.nil?             # Skip non-video files
  return false if IMAGES.include?(vcodec) # Skip common image files
  true
end

def usage
  puts "Usage: ".magenta + "my #{File.basename __FILE__} [-arg] [files...]".light_blue
  puts
  puts "args:".magenta
  puts "0".blue + "    Flip horizontally".yellow
  puts "1".blue + "    Rotate 90 degrees clockwise".yellow
  puts "2".blue + "    Rotate 90 degrees counter-clockwise".yellow
  puts "3".blue + "    Flip vertically and rotate 90 degrees clockwise".yellow
end

if ARGV.size == 0
  usage
  exit 0
end

if ARGV.first =~ /-\d/
  arg = ARGV.first[1]
  files = ARGV[1..ARGV.size]
else
  arg = "1"
  files = ARGV
end

files.each do |file|
  if is_video(file)
    ext = file.split(".").last
    basename = File.basename(file, ".#{ext}")
    outfile = "#{basename}_#{arg}_rotated.#{ext}"
    print "Rotating #{file}..."
    system("ffmpeg -v error -i #{file.shellescape} -vf 'transpose=#{arg}' #{outfile.shellescape}")
    puts "Done.".green
  else
    print "#{file}: "
    puts "not a video file.".yellow
  end
end