normalize-video.rb

# Author: Ayose Cazorla
# Public Domain
#
# Normalize a lot of videos using ffmpeg and normalize-audio (both available as Debian packages)
# 
# HRC on tha house...

AMPLITUDE="-12dBFS"

def say(msg)
  $stdout.print "\r#{msg}\033[K"
  $stdout.flush
end

def run(*args)
  Process.waitpid(fork do
    STDIN.reopen("/dev/null", "r")
    STDERR.reopen("/dev/null", "w")
    STDOUT.reopen("/dev/null", "w")
    exec(*args)
  end)
  $?.success?
end

NumProcessors = File.read("/proc/cpuinfo").grep(/^processor\s+:\s+\d+\s*$/).size
MainThread = Thread.current

StreamFiles = {}
VideoFiles = ARGV.grep(/^(?!-)/)

Dir.mkdir("streams") unless File.directory?("streams")
Dir.mkdir("normalized") unless File.directory?("normalized")

def extract_streams(filename)
  basename = File.basename(filename)
  dest_audio = "streams/#{basename}.wav"
  dest_video = "streams/noaudio-#{basename}"

  if run("ffmpeg", "-y", "-i", filename, "-vn", "-sameq", "-acodec", "pcm_s16le", "-ac", "2", "-ar", "44100", dest_audio) and
     run("ffmpeg", "-y", "-i", filename, "-an", "-vcodec", "copy", dest_video)
    StreamFiles[filename] = { :audio => dest_audio, :video => dest_video }
  end
end

VideoFiles.each_with_index do |filename, index|
  say "Extracting #{index + 1}/#{VideoFiles.size}..."
  Thread.new { extract_streams filename }

  sleep 0.5 while Thread.list.size > NumProcessors
end

sleep 0.5 while Thread.list.size > 1

say "Normalizing..."
puts

system "normalize-audio -a #{AMPLITUDE} streams/*.wav"

puts "Creating new videos..."
n = 0
StreamFiles.each_pair do |video_name, stream|
  n += 1
  Thread.new do
    say "[#{n} / #{StreamFiles.size}] Writing normalized"
    run "ffmpeg", "-y",  "-i", stream[:video],"-i", stream[:audio], "-vcodec", "copy", "-acodec", "libmp3lame", "normalized/#{File.basename video_name}"
    File.unlink stream[:video]
    File.unlink stream[:audio]
  end

  sleep 0.5 while Thread.list.size > NumProcessors
end

sleep 0.5 while Thread.list.size > 1
say "Done"
puts