module MultimediaParadise

# File lib/multimedia_paradise/audio/playlist/playlist.rb, line 1601
def self.add_this_song_to_the_playlist(i)
  ::MultimediaParadise::Playlist.add(i)
end

# File lib/multimedia_paradise/toplevel_methods/analyze_audio_stream.rb, line 21
def self.analyze_audio_stream(
    of_this_file
  )
  ffmpeg_analyze_audio_stream(of_this_file)
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 801
def self.analyze_this_directory_for_id3_tags(i = Dir.pwd)
  require 'id3lib'
  all_files = Dir["#{i}/*.mp3"]
  all_files.each {|this_mp3_file|
    verbose_analyse_this_mp3_file_for_id3_tags(this_mp3_file)
  }
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 293
def self.any_to_mp3(this_file, to = '.mp3')
  ::MultimediaParadise.general_format_conversion(this_file, to)
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 382
def self.append_silence_to_this_song(
    add_this_delay      = 5,
    work_on_these_songs = ['foobar.mp3']
  )
  [work_on_these_songs].flatten.compact.each {|this_song|
    if File.exist? this_song
      cmd = "sox #{this_song} padded_#{this_song} pad 0 #{add_this_delay.to_f}"
      esystem cmd
    else
      e 'No file exists at '+this_song.to_s+'.'
    end
  }
end

# File lib/multimedia_paradise/commandline/menu.rb, line 31
def self.array_commandline_arguments?
  @array_commandline_arguments
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 529
def self.au_to_wav(
    this_file, to = 'wav'
  )
  ::MultimediaParadise.general_format_conversion(this_file, to: ot)
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 594
def self.audio_info(i)
  if i.is_a? Array
    i.each {|entry| audio_info(entry) }
  else
    # cmd = 'sox '+i+' -e stat'
    cmd = 'ffprobe '+i
    run_sys_command cmd
  end
end

# File lib/multimedia_paradise/audio/audio_player/audio_player.rb, line 63
def self.audio_player(options = nil)
  MultimediaParadise::AudioPlayer.new(options)
end

# File lib/multimedia_paradise/toplevel_methods/return_all_video_files.rb, line 20
def self.available_video_files
  Dir["#{realvids_directory?}**"].select {|entry| is_a_video_file?(entry) }.sort
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 520
def self.avi_to_flash(file)
  run_sys_command 'ffmpeg -i '+file+' '+file+'.flv'
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 429
def self.avi_to_m4v(
    output_file = 'output.m4v', *input_files
  )
  output_file = 'output.m4v' if output_file.nil?
  output_file = 'output.'+output_file unless output_file.include? '.'
  _  = 'ffmpeg '.dup
  _ << '-i '+input_files.join(' ')+' '
  _ << '-r 12.5 '
  _ << '-b 80 '
  _ << '-vcodec libxvid '
  _ << '-maxrate 80 '
  _ << '-bufsize 5 '
  _ << output_file
  run_sys_command _
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 41
def self.bin_dir?
  RbConfig::CONFIG['bindir'].to_s+'/' # Ensure trailing '/'.
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 292
def self.bitrate_of_this_song(this_song)
  use_this_regex = /(\d{1,3} ?kb)\/s/ # See: https://rubular.com/r/CfmHoK5w0goYpU
  if this_song.is_a? Array
    this_song = this_song.first
  end
  result = `ffprobe #{this_song} 2>&1 | grep Stream`.strip
  result = result.scan(use_this_regex).flatten.first.to_s
  return result
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 756
def self.capture_screen(size_angabe = '1024x800')
  begin
    require 'capture_screen'
  rescue LoadError; end
  img_file = '$MY_TEMP/GRABBED_X11_screencast.mov'
  _ = CaptureScreen.new :dont_run_yet
  _.store_here = img_file
  _.size = size_angabe
  return _.main_string?
end

# File lib/multimedia_paradise/constants/directory_constants.rb, line 62
def self.cartoons_directory?
  CARTOONS_DIRECTORY
end

# File lib/multimedia_paradise/toplevel_methods/files_and_directories.rb, line 86
def self.chdir(i)
  Dir.chdir(i) if File.directory? i
end

# File lib/multimedia_paradise/toplevel_methods/chop_into_segments_of_n_seconds_size.rb, line 25
def self.chop_into_segments_of_n_seconds_size(
    this_file, # <- Your target file that will be chopped up.
    n_seconds = 60
  )
  ffmpeg_chop_into_segments_of_n_seconds_size(this_file, n_seconds)
end

# File lib/multimedia_paradise/toplevel_methods/chop_off_first_five_minutes.rb, line 12
def self.chop_off_first_five_minutes(of_this_file)
  MultimediaParadise.chop_off_first_n_seconds(
    '5 minutes', of_this_file, :do_create_complementary_file
  )
end

# File lib/multimedia_paradise/toplevel_methods/chop_off_first_n_seconds.rb, line 44
def self.chop_off_first_n_seconds(
    n_seconds                         = TEN_MINUTES, # 10 minutes.
    of_this_multimedia_file           = ARGV,
    also_do_create_complementary_file = false
  )
  if of_this_multimedia_file.is_a? Array
    of_this_multimedia_file.each {|entry|
      chop_off_first_n_seconds(n_seconds, entry, also_do_create_complementary_file)
    }
  else
    case n_seconds
    when '10 minutes'
      n_seconds = TEN_MINUTES
    when '5 minutes'
      n_seconds = FIVE_MINUTES
    when :default
      n_seconds = TEN_MINUTES
    end
    case also_do_create_complementary_file
    when :do_create_complementary_file
      also_do_create_complementary_file = true
    end
    ffmpeg_command = 'ffmpeg -ss 0 -t '+n_seconds.to_s+' -i '+of_this_multimedia_file
    extname        = File.extname(of_this_multimedia_file)
    output_file    = of_this_multimedia_file.sub(/(#{extname})/, '_CHOPPED_AT_THE_START\\1')
    ffmpeg_command << ' '+output_file
    esystem ffmpeg_command
    # ===================================================================== #
    # Also create the "missing" part of the multimedia file, so that
    # we will end up with two files as a result.
    # ===================================================================== #
    if also_do_create_complementary_file
      e 'Now also creating the complementary file.'
      duration       = ::MultimediaParadise.return_duration_of_this_multimedia_file(of_this_multimedia_file) - n_seconds.to_f
      ffmpeg_command = 'ffmpeg -ss '+n_seconds.to_s+' -t '+duration.to_s+' -i '+of_this_multimedia_file
      extname        = File.extname(of_this_multimedia_file)
      output_file    = of_this_multimedia_file.sub(/(#{extname})/, '_CHOPPED_AT_THE_END\\1')
      ffmpeg_command << ' '+output_file
      e orange(ffmpeg_command)
      system ffmpeg_command
    end
  end
end

# File lib/multimedia_paradise/toplevel_methods/chop_off_first_ten_minutes.rb, line 12
def self.chop_off_first_ten_minutes(of_this_file)
  MultimediaParadise.chop_off_first_n_seconds(
    '10 minutes', of_this_file, :do_create_complementary_file
  )
end

# File lib/multimedia_paradise/toplevel_methods/chop_off_first_two_minutes.rb, line 14
def self.chop_off_first_two_minutes(of_this_file)
  MultimediaParadise.chop_off_first_n_seconds(
    '2 minutes', of_this_file, :do_create_complementary_file
  )
end

# File lib/multimedia_paradise/toplevel_methods/codecs.rb, line 28
def self.codec_conversion(
    of_this_input_file,
    use_this_codec = :libvorbis
  )
  if of_this_input_file.is_a? Array
    of_this_input_file = of_this_input_file.join(' ').strip
  end
  output_file = of_this_input_file.
                sub(/#{File.extname(of_this_input_file)}/,'')+
                '.ogg'
  _ = 'ffmpeg -i '+of_this_input_file+' -c:a '+
       use_this_codec.to_s+
       output_file
  e
  esystem _
  e
end

# File lib/multimedia_paradise/audio/compress.rb, line 89
def self.compress_this_audio_file(this_audio_file)
  MultimediaParadise::Compress.new(this_audio_file)
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 817
def self.compress_this_ogg_file(i = 'foobar.ogg')
  _ = 'ffmpeg -i '+entry+' '\
      '-c:a libvorbis -ab 32k '\
      '-ar 22050'\
      ' OUTPUT_'+i
  e
  esystem _
  e
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 560
def self.convert_these_images_into_a_video(*images)
  _ = 'ffmpeg -f image2 -i '+images.join(' ').strip+' video.mpg'
  esystem _
end

# File lib/multimedia_paradise/toplevel_methods/copy_and_merge_this_video_n_times.rb, line 19
def self.copy_and_merge_this_video_n_times(
    this_video, n_times = 3
  )
  if this_video.is_a? Array
    this_video = this_video.join(' ').strip
  end
  n_times = 3 if n_times.nil? # <- Set the default here.
  array = []
  extname = File.extname(this_video)
  # ========================================================================= #
  # Create intermediate files next.
  # ========================================================================= #
  n_times.to_i.times {|number|
    this_new_video_file = 'foobar_'+this_video.sub(/#{extname}$/,'').to_s+
                          '_'+number.to_s+extname
    array << this_new_video_file
    copy_file(this_video, this_new_video_file)
  }
  # ========================================================================= #
  # Past this point we assume that the files were copied successfully.
  # We will next proceed to merge these files.
  # ========================================================================= #
  result = ::MultimediaParadise.merge_these_videos(
    array
  )
  return result
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 56
def self.copy_bin_directory
  file_installed_binaries = "#{MultimediaParadise.project_base_directory?}"\
                            "yaml/internal/installed_binaries.yml"
  mkdir('bin/')
  cd('bin/')
  if File.exist? file_installed_binaries
    e 'Making use of the file '+sfile(file_installed_binaries)+'.'
    install_these_binaries = YAML.load_file(file_installed_binaries)
    installation_directory = `gem env`.split("\n").select {|line| # Check for INSTALLATION DIRECTORY: /root/.gem
      line.include? 'INSTALLATION DIRECTORY:'
    }.first.
    scan(/INSTALLATION DIRECTORY: (.+)$/).flatten.first
    install_these_binaries.each {|entry|
      target = installation_directory+'/bin/'+entry
      if File.exist? target
        e "Copying the file #{target} into the current working "\
          "directory next."
        copy_file(target, Dir.pwd)
      else
        # ================================================================= #
        # Since as of January 2023 first try the bin_dir, before giving up.
        # ================================================================= #
        target = MultimediaParadise.bin_dir?+File.basename(entry)
        if File.exist? target
          e "Copying the file #{target} into the current working "\
            "directory next."
          copy_file(target, Dir.pwd)
        else
          no_file_exists_at(target)
        end
      end
    }
  end
end

# File lib/multimedia_paradise/toplevel_methods/copy_file.rb, line 14
def self.copy_file(from, to)
  FileUtils.cp(from, to)
end

# File lib/multimedia_paradise/video/copy_missing_video_files.rb, line 285
def self.copy_missing_video_files(i = ARGV.first)
  MultimediaParadise::Video::CopyMissingVideoFiles.new(i)
end

# File lib/multimedia_paradise/video/copy_random_video.rb, line 90
def self.copy_random_video(i)
  MultimediaParadise::CopyRandomVideo.new(i)
end

# File lib/multimedia_paradise/video/correct_video_numbers.rb, line 270
def self.correct_video_numbers(i)
  MultimediaParadise::Video::CorrectVideoNumbers.new(i)
end

# File lib/multimedia_paradise/video/create_dvd.rb, line 26
def self.create_dvd(
    input_file = 'video.avi'
  )
  output_mpg_file = 'dvd.mpg'
  e 'We will create a .mpg file called '+sfile(output_mpg_file)+'.'
  _ = 'ffmpeg -i '+input_file+' -aspect 16:9 -target pal-dvd '+output_mpg_file
  esystem(_)
  e 'Next adding this .mpg file ('+output_mpg_file+') to the project '\
    'via '+orange('dvdauthor')+':'
  _ = 'dvdauthor -o dvd/ -t '+output_mpg_file
  esystem(_)
  # ======================================================================= #
  # Use PAL next:
  # ======================================================================= #
  ENV['VIDEO_FORMAT'] = 'PAL'
  _ = 'dvdauthor -o dvd/ -T'
  esystem(_)
  e 'Next creating an .iso file using mkisofs:'
  iso_file = 'dvd.iso'
  _ = "mkisofs -dvd-video -o #{iso_file} dvd/"
  esystem(_)
  e 'All should be finished now! You can burn the file `'+iso_file+'`.'
end

# File lib/multimedia_paradise/audio/create_m3u_playlist.rb, line 237
def self.create_m3u_playlist(i = :default_playlist)
  ::MultimediaParadise::CreateM3uPlaylist.new(i)
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 147
def self.create_noise_profile(
    of_this_mp3_file
  )
  array_results = []
  [of_this_mp3_file].flatten.compact.each {|work_on_this_mp3_file|
    work_on_this_mp3_file = File.absolute_path(work_on_this_mp3_file)
    filename_without_extension = work_on_this_mp3_file.delete_suffix('.mp3')
    this_profile_file_is_to_be_created = "noise_profile_based_on_#{File.basename(filename_without_extension)}"
    if File.exist?(this_profile_file_is_to_be_created) # Always remove old profiles.
      File.delete(this_profile_file_is_to_be_created)
    end
    cmd_to_run = "sox #{work_on_this_mp3_file} -n noiseprof #{this_profile_file_is_to_be_created}.profile"
    e cmd_to_run
    `#{cmd_to_run}`
    array_results << this_profile_file_is_to_be_created
  }
  return array_results
end

# File lib/multimedia_paradise/toplevel_methods/create_video_from_this_audio.rb, line 25
def self.create_video_from_this_audio(
    this_audio_file = ARGV,
    use_this_image  = 'CAT.png'
  )
  if this_audio_file.is_a? Array
    this_audio_file.each {|entry|
      MultimediaParadise.create_video_from_this_audio(entry)
    }
  else
    unless File.exist? use_this_image
      e "No file called `#{use_this_image}` exists."
      e 'Trying to find any other image in this directory next.'
      all_image_files = Dir['*'].select {|entry| is_an_image_file?(entry) }
      # =================================================================== #
      # Must check whether it is empty or not.
      # =================================================================== #
      if all_image_files.empty?
        e 'No image could be found, thus no image was supplied. This is'
        e 'not allowed, so we exit here.'
        return
      else
        # ================================================================= #
        # Ok, use that image in this case - the first one.
        # ================================================================= #
        use_this_image = all_image_files.first.to_s
      end
    end
    output_file = this_audio_file.sub(/#{File.extname(this_audio_file)}/,'')+'.mp4'
    _ = 'ffmpeg -loop 1 '\
        '-i '+use_this_image.to_s+' '\
        '-i '+this_audio_file+' -c:a copy -c:v libx264 '\
        '-shortest '+output_file
    esystem(_)
  end
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 867
def self.crop_this_video(
    i           = 'input.mp4',
    output_file = 'output.mp4'
  )
  [i].flatten.compact.each {|this_video_file|
    esystem 'ffmpeg -i '+
            this_video_file.to_s+
            ' -filter:v "crop=w:h:x:y" '+
            output_file.to_s
  }
end

# File lib/multimedia_paradise/toplevel_methods/cut_from_to.rb, line 57
def self.cut_from_to(
    from_to_position = '',
    hash             = {}
  )
  use_this_file = nil
  start_position = '00:00:00.0' # This is the starting position.
  duration       = nil
  if hash.is_a? String
    hash = { this_file: hash }
  end
  if from_to_position.is_a?(Hash) and hash.is_a?(Hash)
    hash.update(from_to_position)
    from_to_position = '' # And re-set to the old default again.
  end
  if hash.is_a?(Hash) and hash.has_key?(:this_file)
    # ===================================================================== #
    # Designate the file that is to be used next:
    # ===================================================================== #
    use_this_file = hash.delete(:this_file)
  end
  case use_this_file
  # ======================================================================= #
  # === :default
  # ======================================================================= #
  when :default
    use_this_file =
      'TALES_FROM_THE_CRYPT/Tales_from_the_crypt_S06E11_Surprise_Party.mkv'
  end
  if use_this_file.start_with? 'TALES_FROM_THE_CRYPT/'
    use_this_file = use_this_file.dup if use_this_file.frozen?
    use_this_file.sub!(
      Regexp.quote('TALES_FROM_THE_CRYPT/'),
      "#{HOME_DIRECTORY_OF_USER_X}VIDEO/Tales_from_the_crypt/"
    )
  end
  if hash.is_a? Hash
    if hash.has_key?(:to)
      duration = hash[:to]
    end
  end
  if from_to_position.is_a?(String) and from_to_position.frozen?
    from_to_position = from_to_position.dup
  end
  if use_this_file
    # ===================================================================== #
    # The input contains a valid file.
    # ===================================================================== #
    if File.exist? use_this_file
      _ = "ffmpeg -i #{use_this_file} -c copy".dup
      if from_to_position.is_a?(String)
        from_to_position.delete!(' ')
      end
      seek_this_token = '-' # <- This can be '-' or '/'.
      if from_to_position.is_a? String
        if from_to_position.include? '/'
          seek_this_token = '/'
        end
        if from_to_position.include?(seek_this_token)
          splitted = from_to_position.split(seek_this_token)
          start_position = splitted.first
          duration = splitted.last
        end
      end
      _ << " -ss #{start_position}"
      _ << " -t #{duration}"
      dirname = "#{File.dirname(use_this_file)}/".squeeze '/'
      output_file = dirname+'output_'+File.basename(use_this_file)
      _ << " #{output_file}"
      esystem _
      if File.exist? output_file
        e "Created file at `#{sfile(output_file)}`."
        return File.absolute_path(output_file) # And return it here, just to make this method more useful.
      end
    else
      e "No file exists at #{use_this_file}."
    end
  else
    e 'Please provide a valid file, via a key called '\
      ':this_file as part of the second argument '\
      '(which is a Hash).'
  end
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 304
def self.decrease_volume(
    of_this_file,
    by_how_much = '0.5'
  )
  run_sys_command 'sox --volume '+
                   by_how_much+' '+of_this_file+' AUDIO_REDUCED_'+of_this_file 
end

# File lib/multimedia_paradise/toplevel_methods/delay_audio.rb, line 19
def self.delay_audio(
    this_file = ARGV,
    by        = '3.85 seconds' # <- Input your delay here.
  )
  ffmpeg_delay_audio(this_file, by)
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 478
def self.demultiplex(this_file)
  cmd  = 'tcdemux -i '.dup
  cmd << this_file
  cmd << ' -x ac3 > bla.ac3'
  run_sys_command cmd
end

# File lib/multimedia_paradise/toplevel_methods/denoise.rb, line 25
def self.denoise(
    input_file,
    lowpass_value  = 3000,
    highpass_value =  200
  )
  ffmpeg_denoise(input_file, lowpass_value, highpass_value)
end

# File lib/multimedia_paradise/toplevel_methods/deshake.rb, line 23
def self.deshake(input_file = nil)
  if input_file.is_a? Array
    input_file.each {|entry|
      deshake(entry)
    }
  else
    output_file = "output_#{input_file}"
    use_this_command = "ffmpeg -i #{input_file} -vf deshake #{output_file}"
    e
    e use_this_command
    e
    system use_this_command
  end
  
end

# File lib/multimedia_paradise/constants/directory_constants.rb, line 104
def self.directory_to_the_local_songs?
  DIRECTORY_TO_THE_LOCAL_SONGS
end

# File lib/multimedia_paradise/toplevel_methods/radio.rb, line 357
def self.display_radio_stations
  e sfile(
      FILE_RADIO_STATIONS
    )
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 823
def self.display_warning(what_kind_of_warning)
  case what_kind_of_warning
  when :lossy
    e 'Warning: Converting from one lossy format to another '\
      'lossy format.'
  end
end

# File lib/multimedia_paradise/toplevel_methods/e.rb, line 12
def self.e(i = '')
  puts i
end

# File lib/multimedia_paradise/colours/colours.rb, line 50
def self.eimportant(i)
  e ::MultimediaParadise.simp(i)
end

# File lib/multimedia_paradise/toplevel_methods/subtitles.rb, line 44
def self.embed_this_subtitle_onto_that_video(
    this_subtitle, that_video
  )
  output_file = 'output.mp4'
  _ = 'ffmpeg -i '+that_video+' -i '+this_subtitle+
      ' -c copy -c:s mov_text '+output_file
  e
  esystem _
  e
end

# File lib/multimedia_paradise/sinatra/embeddable_interface.rb, line 373
def self.embeddable_interface
  object = Object.new
  object.extend(MultimediaParadise::EmbeddableInterface)
  return object
end

# File lib/multimedia_paradise/toplevel_methods/encode_this_video.rb, line 24
def self.encode_this_video(
    i = ARGV, use_this_mode = :CRF
  )
  [i].flatten.compact.each {|this_video|
    if File.exist? this_video
      output_filename = 'output_'+
                        this_video.
                        sub(/#{File.extname(this_video)}$/,'')+
                        '.mkv'
      case use_this_mode
      when :CRF, :default
        _ = 'ffmpeg -i '+this_video+' -c:v libx264 '\
            '-preset slow -crf 22 -c:a copy '+output_filename
        esystem _
      end
    else
      e 'No file exists at '+this_video+'.'
    end
  }
end

# File lib/multimedia_paradise/toplevel_methods/ensure_that_the_output_directory_exists.rb, line 17
def self.ensure_that_the_output_directory_exists(
    output_directory = MultimediaParadise.output_directory?
  )
  unless File.exist? output_directory
    FileUtils.mkdir_p(
      output_directory
    )
  end
end

# File lib/multimedia_paradise/toplevel_methods/esystem.rb, line 21
def self.esystem(
    i, optional_colour_to_use = nil
  )
  Signal.trap('SIGINT') { exit }
  i = i.dup if i.frozen?
  i.strip!
  display_this_string = i.dup
  if optional_colour_to_use
    if optional_colour_to_use.is_a?(Hash) and
       optional_colour_to_use.has_key?(:colour)
      use_this_colour = optional_colour_to_use[:colour]
      display_this_string = COLOURS.send(use_this_colour, display_this_string) 
    end
  end
  e display_this_string
  system i
end

# File lib/multimedia_paradise/audio/extract_audio/extract_audio.rb, line 393
def self.extract_audio(
    i,
    optional_store_where = :default,
    &block
  )
  if i.is_a? Array
    i.each {|entry| # Recursive-call here.
      MultimediaParadise.extract_audio(entry, optional_store_where, &block)
    }
  else
    _ = ::MultimediaParadise::ExtractAudio.new(i, optional_store_where, &block)
    return _.file_location?
  end
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 697
def self.extract_audio_from_until(
    this_file,
    from_start_pos = 30, 
    duration       = 30
  )
  this_file = File.absolute_path(this_file)
  base_dir = File.dirname(this_file)
  output_file = 'CLIPPED_'+File.basename(this_file)
  output_file = base_dir+'/'+output_file
  this_command = 'ffmpeg -y'+ # -y for "automatically overwrite".
                 ' -i '+this_file+' -ss '+from_start_pos.to_s+
                 ' -t '+duration.to_s+' '+output_file
  run_sys_command this_command
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 518
def self.extract_images_from_this_video_file(*i)
  i.flatten.each {|entry|
    _extension_to_use = File.extname(entry) # No longer in use.
    _ = 'ffmpeg '\
        '-i '+entry+
        ' %08d.png' #OUTPUT_'+entry.sub(/#{extension_to_use}$/,'')+
        # extension_to_use+
    e
    esystem _
    e
  }
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 540
def self.extract_one_image_per_second(
    from_this_video_file = 'my_video.mpeg',
    frame_size_to_use    = '75x75'
  )
  extension_to_use = File.extname(from_this_video_file)
  _ = 'ffmpeg -i '+from_this_video_file+
      ' -r 1 '+ # ← Specify the video-frame here, aka "1 image per second".
      '-s '+frame_size_to_use+
      ' OUTPUT_'+from_this_video_file.sub(/#{extension_to_use}$/,'')+
      extension_to_use
  e
  esystem _
  e
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 797
def self.extract_video(this_file)
  new_file_location = nil
  if this_file.is_a? Array
    this_file = this_file.first # For now, we only use the first member.
  end
  name_of_the_extension = File.extname(this_file.delete('.'))
  output_file_name = 'video_extracted_from_'+
                     File.basename(this_file.sub(/\.avi$/,'')).
                     sub(/#{name_of_the_extension}$/,'')+'.avi'
  output_file_name = output_file_name.squeeze('.')
  _ = 'mencoder -idx -ovc copy -nosound '+this_file+' -o '+output_file_name
  run_sys_command _ if _
  new_file_location = output_file_name
  return new_file_location
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 462
def self.ffmpeg_analyze_audio_stream(
    of_this_file
  )
  hash = {}
  of_this_file = [of_this_file].flatten.compact
  of_this_file.each {|this_file|
    hash[this_file] = {}
    _ = 'ffmpeg -i '+this_file+' -af "volumedetect" -f null /dev/null 2>&1'
    e
    result = `#{_}`
    max_volume_is = result.scan(/max_volume: (.+)$/).flatten.first.sub(/ dB/,'').to_f
    hash[this_file][:maximum_volume] = max_volume_is # in decibel, dB.
    mean_volume_is = result.scan(/mean_volume: (.+)$/).flatten.first.sub(/ dB/,'').to_f
    hash[this_file][:mean_volume] = mean_volume_is
  }
  hash
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 333
def self.ffmpeg_chop_into_segments_of_n_seconds_size(
    this_file, # <- Your target file that will be chopped up.
    n_seconds = 60
  )
  if this_file
    this_file = this_file.dup if this_file.frozen?
    extname = File.extname(this_file)
    filename = this_file.sub(/#{extname}/,'')
    _ = 'ffmpeg -i '+this_file+' -f segment -segment_time '+n_seconds.to_s+' -c copy out_'+filename+'_%03d'+extname
    esystem(_)
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 63
def self.ffmpeg_chroma_subsampling(this_video)
  esystem 'ffmpeg -i '+this_video+' -vf format=yuv420p output.mp4'
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 565
def self.ffmpeg_convert_this_multimedia_file(
    input_file  = 'input.mp3',
    output_file = :mkv #'output.ogg'
  )
  yielded = nil
  if block_given?
    yielded = yield
  end
  if File.exist? input_file
    case output_file
    when :mkv
      extname = File.extname(input_file)
      use_this_name = input_file.
                      sub(/#{extname}$/,'')
      output_file = use_this_name+'.mkv'
    end
    _ = "ffmpeg -i #{input_file}"
    case yielded
    # ===================================================================== #
    # === :copy_audio
    # ===================================================================== #
    when :copy_audio
      _ << ' -c:a copy' 
    # ===================================================================== #
    # === :libvorbis_audiostream
    # ===================================================================== #
    when :libvorbis_audiostream
      _ << ' -c:a libvorbis'
    # ===================================================================== #
    # === :vp9_codec
    # ===================================================================== #
    when :vp9_codec
      _ << ' -c:v vp9' 
    else
      if yielded.is_a? Hash
        # ================================================================= #
        # === :framerate
        # ================================================================= #
        if yielded.has_key? :framerate
          _ << " -r #{yielded.delete(:framerate)}"
        end
      end
    end
    _ << " #{output_file}"
    e _
    system _
  else
    e 'No file exists at '+input_file+'.'
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 77
def self.ffmpeg_deinterlace_this_video(this_video)
  esystem 'ffmpeg -i '+this_video+' -vf yadif output.mp4'
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 415
def self.ffmpeg_delay_audio(
    this_file = ARGV,
    by        = '3.85 seconds' # <- Input your delay here.
  )
  if this_file.is_a? Array
    this_file.each {|entry|
      ffmpeg_delay_audio(entry, by)
    }
  else
    by = by.to_s # Need a String past this point here.
    by.sub!(/ seconds/,'') if by.include? ' seconds' # Strip away ' seconds'.
    _ = 'ffmpeg -i "'+this_file+'"'.dup
    _ << ' -itsoffset '+by
    _ << ' -map 0:v -map 1:a -c copy'
    # ===================================================================== #
    # Next, determine the output-file.
    # ===================================================================== #
    _ << ' "OUTPUT_WITH_DELAYED_AUDIO_'+this_file+'"'
    esystem _
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 360
def self.ffmpeg_denoise(
    input_file,
    lowpass_value  = 3000,
    highpass_value =  200
  )
  if input_file.is_a? Array
    if input_file.empty?
      opn; e "Please provide at the least one file name to the method "\
             "#{sfancy(__method__.to_s+'()')}"
    else
      input_file.each {|entry|
        ffmpeg_denoise(entry, lowpass_value, highpass_value)
      }
    end
  else
    _ = 'ffmpeg -i '+input_file+' '
    _ << '-af "'
    _ << 'lowpass=f='+lowpass_value.to_s+','
    _ << 'highpass=f='+highpass_value.to_s
    _ << '" '
    _ << 'denoised_output_'+input_file.to_s
    esystem _
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 542
def self.ffmpeg_extract_audio(
    i = input.mkv, # The input filename.
    o = :ogg       # The output filename.
  )
  extname = File.extname(i)
  case o
  when :ogg
    use_this_name = i.
                    sub(/#{extname}$/,'')
    o = use_this_name+'.ogg'
  end
  esystem 'ffmpeg -i '+i+' -vn '+o
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 531
def self.ffmpeg_flip_video_to_the_left(i)
  _ = "ffmpeg -i #{i} -vf transpose=2 flipped_to_the_left_#{i}"
  esystem _
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 516
def self.ffmpeg_flip_video_to_the_right(i)
  _ = "ffmpeg -i #{i} -vf transpose=1 flipped_to_the_right_#{i}"
  esystem _
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 215
def self.ffmpeg_horizontal_flip(this_video_file)
  if this_video_file.is_a? Array
    this_video_file.each {|entry| horizontal_flip(entry) }
  else
    extname = File.extname(this_video_file)
    output_name = 'horizontal_flip_'+this_video_file.sub(/#{extname}/,'')+extname
    _ = 'ffmpeg -i '+this_video_file+' -vf "hflip" '+output_name
    esystem _
    output_name # <- Also return the output filename here.
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 255
def self.ffmpeg_increase_volume_of_this_audio_file(
    input_file,
    modify_volume_by_this_value = '5.0' # or 3.0 or 4.0 and so forth.
  )
  [input_file].flatten.compact.each {|this_file|
    _ = 'ffmpeg -i '+this_file+' -vcodec copy -af "volume='+modify_volume_by_this_value.to_s+
       '" output_'+this_file
    esystem _
  }
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 162
def self.ffmpeg_query_the_audio_codec_of_this_file(i)
  # ======================================================================= #
  # See: https://rubular.com/r/8KrR1NTUq9hQU8
  # ======================================================================= #
  use_this_regex = /Audio: ([a-zA-Z0-9]{0,10})/
  result = []
  i = [i].flatten.map
  i.each {|this_file|
    _ = `ffmpeg -i #{this_file} 2>&1`.split("\n")
    _.select! {|line|
      line.include? ': Audio: '
    }
    _.map! {|entry|
      entry =~ use_this_regex
      $1.to_s.dup
    }
    result << _.first
  }
  result
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 39
def self.ffmpeg_return_image_from_this_video_file(
    input_file = 'input.mp4',
    starting_position = 5, # in n seconds
    width_and_height_for_the_image = '480x270'
  )
  esystem 'ffmpeg -i '+input_file+' -vframes 1 -an -s '+
          width_and_height_for_the_image.to_s+' '+
          '-y -ss '+
          starting_position.to_s+' output.jpg'
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 243
def self.ffmpeg_rotate_this_video_file_by_90_degrees(
    this_video_file
  )
  output_file = 'output_'+this_video_file+'.mp4' 
  _ = 'ffmpeg -i '+this_video_file+' -vf transpose=1 '+output_file
  esystem _
  output_file # <- And return the output file too.
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 98
def self.ffmpeg_scale_this_video(
    this_video, optional_hash = {}
  )
  if this_video.is_a? Array
    this_video.each {|entry| ffmpeg_scale_this_video(entry) }
  else
    use_this_as_output_file = 'output.mp4'
    cmd = ''.dup
    cmd << 'ffmpeg -i'
    cmd << " #{this_video}"
    # ===================================================================== #
    # Height and width must be determined before the next step. Set them to
    # nil first.
    # ===================================================================== #
    width = nil
    height = nil
    if optional_hash.is_a? Hash
      # ======================================================================= #
      # === :height
      # ======================================================================= #
      if optional_hash.has_key? :height
        height = optional_hash.delete(:height)
      end
      # ======================================================================= #
      # === :width
      # ======================================================================= #
      if optional_hash.has_key? :width
        width = optional_hash.delete(:width)
      end
    end
    if width.nil?
      width = 1080 # Currently hardcoded on purpose. Used to be 640 in the past.
    end
    if height.nil?
      height = -1
    end
    cmd << " -vf scale=#{width}:#{height}"
    if File.exist? use_this_as_output_file
      random_number = rand(100)+1 # Pick a "random" name for the file.
      use_this_as_output_file = "output#{random_number}.mp4"
    end
    # ===================================================================== #
    # Add the name of the output file next:
    # ===================================================================== #
    cmd << " #{use_this_as_output_file}"
    e
    esystem cmd
    e
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 492
def self.ffmpeg_slow_down_this_video_file(
    this_video_file  = ARGV,
    pts_value_to_use = 2.0
  )
  if this_video_file.is_a? Array
    this_video_file.each {|entry|
      ffmpeg_slow_down_this_video_file(entry, pts_value_to_use)
    }
  else
    # ===================================================================== #
    # To slow down a video, a  multiplier greater than 1 has to be used:
    # ===================================================================== #
    _ = "ffmpeg -i #{this_video_file} -filter:v \"setpts=#{pts_value_to_use}*PTS\" "\
        "OUTPUT_SLOWED_DOWN_VIDEO_#{this_video_file}"
    esystem _
  end
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 295
def self.ffmpeg_start_screencast(
    use_this_screen_resolution = return_screen_resolution, # <- We will use the default screen-resolution here.
    output_filename            = 'screencast',
    use_this_framerate         = '25',
    use_this_video_codec       = 'huffyuv' # <- or libx264, for instance.
  )
  # ======================================================================= #
  # Must use a proper output-format. By default this will be .mkv,
  # although it could also be .avi.
  # ======================================================================= #
  unless output_filename.include? '.'
    output_filename = output_filename.dup if output_filename.frozen?
    output_filename << '.mkv'
  end
  _ = 'ffmpeg -f x11grab -r '+
      use_this_framerate.to_s+' -s '
  _ << use_this_screen_resolution+' '
  _ << ' -i :0.0 '
  _ << '-vcodec '+use_this_video_codec+' '
  #_ << '-f alsa -i hw:0 '
  _ << ' '+output_filename
  esystem _
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 22
def self.ffmpeg_to_mp4(*these_files)
  output_file = 'foobar.mp4'
  _ = 'ffmpeg -i '+[these_files].flatten.compact.join(' ')+
      ' -vcodec copy -acodec copy '+
      output_file
  esystem _
  return output_file
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 396
def self.ffmpeg_use_lame_codec(
    this_video_file
  )
  this_video_file = [this_video_file].flatten.compact
  this_video_file.each {|video_file|
    output_file = "output_#{File.basename(video_file)}"
    _ = 'ffmpeg -i "'+video_file+
        '" -vcodec copy -acodec libmp3lame "'+output_file+'"'
    esystem _
  }
end

# File lib/multimedia_paradise/ffmpeg/ffmpeg.rb, line 196
def self.ffmpeg_vertical_flip(this_video_file)
  if this_video_file.is_a? Array
    this_video_file.each {|entry| ffmpeg_vertical_flip(entry) }
  else
    extname = File.extname(this_video_file)
    base_dir = File.dirname(this_video_file)
    filename = File.basename(this_video_file)
    output_name = base_dir+'/vertical_flip_'+filename.sub(/#{extname}/,'')+extname
    _ = 'ffmpeg -i '+this_video_file+' -vf "vflip" '+output_name
    esystem _
    output_name # <- Also return the output name here.
  end
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 610
def self.file_does_not_exist(file)
  e "No file exists at `#{sfile(file)}`."
end

# File lib/multimedia_paradise/audio/file_duration/file_duration.rb, line 583
def self.file_duration_of(i)
  duration = ::MultimediaParadise::FileDuration.new(i) {
    :be_quiet_and_we_may_not_exit
  }.duration?
  return duration
end

# File lib/multimedia_paradise/constants/file_constants.rb, line 28
def self.file_lyrics
  FILE_LYRICS
end

# File lib/multimedia_paradise/constants/file_constants.rb, line 106
def self.file_radio_stations
  FILE_RADIO_STATIONS
end

# File lib/multimedia_paradise/constants/file_constants.rb, line 162
def self.file_tales_from_the_crypt
  "#{MultimediaParadise.project_yaml_dir?}tales_from_the_crypt/tales_from_the_crypt.yml"
end

# File lib/multimedia_paradise/constants/file_constants.rb, line 155
def self.file_tv_channels
  "#{PROJECT_YAML_DIRECTORY}tv_channels/tv_channels.yml"
end

# File lib/multimedia_paradise/constants/file_constants.rb, line 140
def self.file_video_collection?
  FILE_VIDEO_COLLECTION
end

# File lib/multimedia_paradise/toplevel_methods/is_video_file.rb, line 51
def self.filter_for_video_files(array)
  array.select {|entry| is_video_file?(entry) }
end

# File lib/multimedia_paradise/toplevel_methods/is_video_file.rb, line 35
def self.filter_for_video_files_from(
    this_directory
  )
  if this_directory.is_a?(String) and File.directory?(this_directory)
    this_directory = Dir["#{this_directory}/*"]
  end
  this_directory.select {|entry|
    is_video_file? entry
  }
end

# File lib/multimedia_paradise/video/find_video/find_video.rb, line 421
def self.find_this_video(
    i,
    be_silent_or_be_verbose = :be_verbose
  )
  _ = MultimediaParadise::FindVideo.new(i, be_silent_or_be_verbose)
  return _.find_video
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 400
def self.flash_to_mp4(input_file = 'input.flv')
  if File.exist? input_file
    cmd  = 'ffmpeg '
    cmd << '-i '+input_file+' '
    cmd << '-an output.mp4  '
    run_sys_command cmd
  end
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 265
def self.flash_to_mpg(
    input_file  = 'jokes.flv',
    output_file = 'jokes.mpg'
  )
  if File.exist? input_file
    cmd = 'ffmpeg -i '
    cmd << input_file
    cmd << ' -ab 56 -ar 22050 -b 500 -s 320×240 '
    cmd << output_file
    run_sys_command cmd
  end
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 701
def self.flip_video_to_the_left(i)
  ffmpeg_flip_video_to_the_left(i)
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 711
def self.flip_video_to_the_right(i)
  ffmpeg_flip_video_to_the_right(i)
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 619
def self.for_ipod
  cmd = 'mencoder -ovc raw -ofps 15 -oac pcm '.dup
  cmd << '-vf scale=176:-2,expand=176:132,format=bgr16 input.file '
  cmd << '-o output.avi'
end

# File lib/multimedia_paradise/conversions/conversions.rb, line 73
def self.general_format_conversion(
    input_file,  # Such as 'foobar.wav'.
    target_file, # Such as 'foobar.mp3'.
    &block
  )
  if input_file.is_a? Array
    input_file.each {|entry|
      general_format_conversion(entry, target_file, &block)
    }
  else
    if target_file.is_a? Hash
      # =================================================================== #
      # === :to
      #
      # Allow support for the ":to" keyword.
      # =================================================================== #
      if target_file.has_key? :to
        target_file = target_file.delete(:to)
      end
    end
    # ===================================================================== #
    # The variable target_file may be a symbol. Check this first.
    #
    # We work on the target_file first.
    # ===================================================================== #
    case target_file.to_s
    # ===================================================================== #
    # === to_webm
    # ===================================================================== #
    when /^to(_|-)?webm$/i,
         /webm$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.webm'
    # ===================================================================== #
    # === to_ogg
    # ===================================================================== #
    when /^to(_|-)?ogg$/i,
         /ogg$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.ogg'
    # ===================================================================== #
    # === to_aac
    # ===================================================================== #
    when /^to(_|-)?aac$/i,
         /\.?aac$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.aac'
    # ===================================================================== #
    # === to_dv
    # ===================================================================== #
    when /^to(_|-)?dv$/i,
         /\.?dv$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.dv'
    # ===================================================================== #
    # === to_wav
    # ===================================================================== #
    when /^to(_|-)?wav$/i,
         /wav$/i,
         '2wav'
      target_file = input_file.gsub(File.extname(input_file), '')+'.wav'
    # ===================================================================== #
    # === to_mp3
    # ===================================================================== #
    when /^to(_|-)?mp3$/i,
         /mp3$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.mp3'
    # ===================================================================== #
    # === to_mp3
    # ===================================================================== #
    when /^to(_|-)?mp3$/i,
         /mp3$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.mp3'
    # ===================================================================== #
    # === to_opus
    # ===================================================================== #
    when /^to(_|-)?opus$/i,
         /opus$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.opus'
    # ===================================================================== #
    # === to_wv
    # ===================================================================== #
    when /^to(_|-)?wv$/i,
         /wv$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.wv'
    # ===================================================================== #
    # === to_wma
    # ===================================================================== #
    when /^to(_|-)?wma$/i,
         /wma$/i
      target_file = input_file.gsub(File.extname(input_file), '')+'.wma'
    end unless target_file.to_s.include?('/')
    # ===================================================================== #
    #          ^^^ here we assume the second argument to be like this: /Depot/j/yodel.wav
    # ===================================================================== #
    # ===================================================================== #
    # The "target_file" variable may be something such as '.wma'
    # In this case, the file name is missing. We fix this problem
    # by using the real name of the input_file as output format.
    # ===================================================================== #
    if target_file.start_with? '.'
      if input_file.include? '.'
        target_file = input_file[0, input_file.index('.')]+target_file
      end
    end if target_file.respond_to? :start_with?
    target_file = rds(target_file)
    target_file = File.absolute_path(target_file)
    if File.exist? input_file
      cliner {
        please_be_patient(
          input_file, 'to '+File.extname(target_file)+' format'
        )
        ::MultimediaParadise.display_warning(:lossy)
      }
      # =================================================================== #
      # By default we will use ffmpeg, but this can be changed to sox or
      # any other toolkit.
      # =================================================================== #
      _ = "#{::MultimediaParadise.use_this_binary_for_conversions?} -y ".dup
      _ << " -i #{input_file} "
      # =================================================================== #
      # Do some ad-hoc clean up next.
      # -ac means audio_channel
      # =================================================================== #
      if target_file.end_with?('.opus')
        _ << '" -ar 48000 -ac 2 -acodec libopus -ab 256k '
      elsif target_file.end_with?('.ogg')
        _ << ' -acodec libvorbis -aq 60 '
      end
      if block_given?
        yielded = yield
        if yielded.is_a? Hash
          # =============================================================== #
          # === :bitrate_to_use
          # =============================================================== #
          if yielded.has_key? :bitrate_to_use
            # -b:a will convert the audio bitrate to be exactly that value.
            _ << ' -b:a '+yielded[:bitrate_to_use].to_s+'k'
          end
        end
      end
      _ << " #{target_file}"
      _.squeeze!(' ')
      run_sys_command _
      # =================================================================== #
      # Since as of August 2016, we will return the path to the newly
      # generated file.
      # =================================================================== #
      return target_file.to_s
    else
      file_does_not_exist(input_file)
    end
  end
end

# File lib/multimedia_paradise/toplevel_methods/misc.rb, line 321
def self.generate_sine_tone(
    n_seconds = 5
  )
  output_file = 'output.wav'
  esystem 'sox -n '+output_file+' synth '+n_seconds.to_s+' sine 440'
  return output_file
end