finalcut.rb

require 'tmpdir'
require 'pathname'
require 'fileutils'
require 'time'
require 'aviglitch'

class FinalCut

  def initialize *paths
    @ffmpeg = exec('which ffmpeg').chomp
    raise 'ffmpeg doesn\'t exist.' if @ffmpeg.empty?
    @mencoder = exec('which mencoder').chomp
    raise 'mencoder doesn\'t exist.' if @mencoder.empty?
    @original_files = paths
    @tmpdir = Dir.mktmpdir
    @base_file = @tmpdir + '/base.avi'
    tmpfiles = paths.map do |f|
      p = Pathname f
#      retrun p.to_s if p.extname == 'avi'
      tmp = @tmpdir + '/' + p.basename.to_s + '.avi'
      exec [@ffmpeg, '-i', p.to_s, '-sameq', tmp].join(' ')
      tmp
    end
    if tmpfiles.size > 1
      exec [@mencoder, '-ovc copy -oac copy', tmpfiles, '-o', @base_file].flatten.join(' ')
    else
      FileUtils.cp tmpfiles.first, @base_file
    end
    @duration = get_duration @base_file
    @cut_files = []
    if block_given?
      yield self
      close
    end
  end

  def cut opts
    id = opts.object_id
    from = opts[:from] || 0
    from = from % @duration
    duration = opts[:duration] || @duration
    duration = @duration if duration == :whole
    duration = duration % @duration unless duration == @duration
    size = opts[:size]
    framerate = opts[:framerate]
    bitrate = opts[:bitrate]
    repeat = opts[:repeat]
    speed = opts[:speed]
    datamosh = opts[:datamosh]
    file1 = out = @tmpdir + "/#{id}a.avi"
    c = [@ffmpeg, '-i', @base_file, '-sameq']
    c += ['-ss', from,
          '-t', duration] unless from == 0 && duration == @duration
    c += ['-r', framerate] unless framerate.nil?
    c += ['-b', bitrate] unless bitrate.nil?
    c += ['-s', size] unless size.nil?
    c << file1
    exec c.join(' ')
    unless repeat.nil?
      file2 = @tmpdir + "/#{id}b.avi"
      c = [@mencoder, 
        '-ovc copy -oac copy',
        '-o', file2
      ]
      c << "#{out} " * repeat
      exec c.join(' ')
      out = file2
    end
    if datamosh
      file3 = @tmpdir + "/#{id}c.avi"
      ag = AviGlitch.open out
      ag.glitch(:keyframe) do |d|
        "\000" * d.size
      end
      ag.output file3
      out = file3
    end
    unless speed.nil?
      file4 = @tmpdir + "/#{id}d.avi"
      c = [@mencoder, 
        '-ovc copy -oac copy',
        '-o', file4,
        '-speed', speed,
        out
      ]
      exec c.join(' ')
      out = file4
    end
    @cut_files << out
    self
  end

  def output outfile, opt = nil
    path = Pathname outfile
    out = @tmpdir + '/' + path.basename.to_s + '.o.avi'
    if @cut_files.size > 1
      c = [@mencoder, 
        '-ovc lavc -oac mp3lame',
        @cut_files.join(' '),
        '-o', out
      ]
      exec c.join(' ')
    else
      out = @cut_files.first
    end
    unless opt == :raw
      file = @tmpdir + '/' + path.basename.to_s
      c = [@ffmpeg, '-i', out, '-sameq -y', file]
      exec c.join(' ')
      out = file
    end
    FileUtils.cp out, path.to_s
    self
  end

  def close
    FileUtils.remove_entry_secure @tmpdir
  end

  def get_duration file = nil
    file ||= @base_file
    res = exec [@ffmpeg, '-i', file].join(' ')
    if res =~ /Duration: ([\d:.]+),/
      Time.parse($1) - Time.parse('00:00')
    else
      raise "Wrong file : #{file}"
    end
  end

  private
    def exec command
      IO.popen(command + ' 2>&1') {|io| io.read }
    end

  class << self
    alias open new
  end
end