Stitch a folder of images into a movie

go.command

#!/bin/bash

root=$(cd $(dirname "$0"); pwd)
cd $root
exec ruby process.rb "$@"

process.rb

require "shellwords"
require "tmpdir"

FRAMES_PER_SECOND = 6

def main
  log_all_output!

  puts "#{Time.now} -- Start"
  dirin = getdir("in")
  dirdone = getdir("done")
  dirout = getdir("out")
  mm = MovieMaker.new dirin, dirdone, dirout

  Dir.entries(dirin).each do |entry|
    next if entry == "." || entry == ".."
    mm.make_movie(entry)
  end
ensure
  puts "#{Time.now} -- Done"
end

class MovieMaker
  def initialize(from, done, to)
    @from = from
    @done = done
    @to = to
  end

  attr_reader :from, :to, :done

  def make_movie(name)
    image_dir = File.join(from, name)
    return skipnondir(name) unless File.directory?(image_dir)
    done_dir = File.join(done, name)
    return doneexists(done_dir) if File.exist?(done_dir)
    File.rename(image_dir, done_dir)
    image_dir = done_dir
    images = Dir["#{image_dir}/*"].select { |p| File.file?(p) }.sort
    return noimages(image_dir) if images.empty?

    movie = File.join(to, "#{Time.now.strftime("%Y-%m-%d-%H-%M-%S")}-#{name}.mp4")

    Dir.mktmpdir do |numbered_dir|
      prep_images images, numbered_dir
      convert_movie numbered_dir, movie
    end
  end

  def skipnondir(name)
    puts "skipping #{name}: not a directory"
  end
  def doneexists(dir)
    puts "#{dir} exists, not reprocessing"
  end
  def noimages(dir)
    puts "skipping #{dir}: empty"
  end

  FORMAT = "%09d.jpg".freeze
  HR = ("-"*40).freeze

  def prep_images(image_paths, numbered_dir)
    image_paths.each_with_index do |file, i|
      File.link file, File.join(numbered_dir, FORMAT % i)
    end
  end

  def convert_movie(numbered_dir, outpath)
    # quicktime can't seem to handle the gigantic images from the dslr.
    # so shrink them to 1024 pixels wide, maintain the current aspect ratio,
    # but also ensure that the height is divisible by two. ?!?!?!?!!
    cmd = [ "/usr/local/bin/ffmpeg", "-hide_banner",
      "-f", "image2",
      "-r", FRAMES_PER_SECOND.to_s,
      "-i", FORMAT,
      "-vcodec", "libx264",
      "-vf", "scale=1024:-2,format=yuv420p",
      "-r", "30",
      outpath ]
    puts HR, "MAKE MOVIE: #{cmd.shelljoin} (in #{numbered_dir})"
    system "ls", "-l", numbered_dir or return
    system(*cmd, :chdir => numbered_dir) or return
    puts HR
    system "ffprobe", "-hide_banner", outpath
  end
end

ROOT = File.expand_path(File.dirname(__FILE__)).freeze
def getdir(name)
  path = File.join(ROOT, name)
  Dir.mkdir(path) unless Dir.exist?(path)
  path
end

def log_all_output!(path = File.join(getdir("log"), Time.now.strftime("%Y-%m-%d-%H-%M-%S-#$$.log")))
  r, w = IO.pipe
  tee_pid = spawn "tee", "-a", path, :in => r
  r.close
  $stdout.reopen(w)
  $stderr.reopen(w)
end

main