gistfile1.rb

require "rubygems"
require "term/ansicolor"
require "tempfile"

class Array
  def split(length=self.length/2)
    sets = Array.new
    self.each_slice(length){|s| sets << s}
    sets
  end
end

class Sound
  include Term::ANSIColor
  attr_accessor :path, :start_sample, :end_sample, :temp
  TEMP_DIR = "temp/"
  `mkdir #{TEMP_DIR}`

  Tempfile.class_eval do
    # overwrite so tempfiles use the extension of the basename.
    # important for conversion
    def make_tmpname(basename, n)
      ext = nil
      sprintf("%s%d-%d%s", basename.to_s.gsub(/\.\w+$/) { |s| ext = s; '' }, $$, n, ext)
    end
  end
  # start and end samples are really for when the clip
  # is part of another file, but it doesnt really
  # matter since you can just use
  # :start_sample => 0, :end_sample => (start+length)
  # temp defines if this is a temporary file or not...
  # if temp then it can be closed, otherwise close does nothing
  #
  def initialize(file_path = false, extension = ".wav", remove_file = true)
    unless file_path
      s = Tempfile.new("sound" + extension, TEMP_DIR)
      self.path = s.path
      self.temp = s
    else
      self.path = file_path
      self.temp = false
    end

    `rm -f #{s.path}` if (remove_file && !file_path) # if we want to use as a holder
  end

  def to_s
    self.path
  end

  def slice(start_sample, end_sample)
    # return a new Sound class that is just a snipet
    s = Sound.new
    len = end_sample - start_sample
    `sox #{path} #{s.path} trim #{start_sample}s #{len}s`
    # trim the sound file and save to the new one
    s.temp = temp # save, so we can close it later
    s.start_sample, s.end_sample = start_sample, end_sample
    return s
  end

  def split(n)
    # split the sound file into n sounds
  end

  def self.concat(sounds)
    # concatinate an array of sound clips
    sets = sounds[1..-1].split(32)
    # copy the first one to the temp
    final = Sound.new
    temp = Sound.new
    `mv #{sounds[0].path} #{final.path}`

    for set in sets
      `cp #{final.path} #{temp.path}` # make a copy for writing
      `sox #{temp.path} #{set.map{|s| s.path + " "} } #{final.path}`
      puts "Appending set starting with chunk #{set[0].id}, #{set.length} chunks in the set"
    end

    return final
  end

  def length
    # return clip length (IN SAMPLES, not time)
    (start_sample - end_sample)
  end

  def encode(extension, file_path = nil)
    # let mmpeg pick the file type based on the extention given
    # returns new Sound object
    return unless path
    s = Sound.new file_path, extension
    `ffmpeg -i #{path} #{s.path}` # -y to overwrite the temp file
    return s
  end

  def play
    temp = self.encode(".wav")
    `play #{temp}`
    temp.close
  end

  def apply_effect(effect)
    # simple way to apply effect to sound clip in, just append to command line 
    puts "  Applying effect #{effect} to clip...".yellow
    temp = Tempfile.new("transfer_file")
    `cp #{path} #{temp.path}` # make a copy for writing
    `sox #{temp.path} #{path} #{effect}`
    temp.close(true) # get rid of the temp file
  end

  def close
    (self.temp).close(true) if self.temp
  end

end

# Usage:
# require "sound"
# a = Sound.new("song.mp3")
# a.play
# ...