Parse video by scene change

parse_video.rb

require "csv"
require "streamio-ffmpeg"
require "interactor"
require "command"
require "bigdecimal"
require "bigdecimal/util"

module Video
  class DetectScenes
    include Interactor

    def before
      fail!(error: "Invalid file path") unless context[:file_path] && File.exists?(file_path)

      context[:video] = FFMPEG::Movie.new(file_path)

      fail!(error: "Invalid video file") unless video.valid?
    end

    def run
      result = Command.run(%Q(ffprobe -show_frames -of compact=p=0 -f lavfi "movie=#{file_path},select=gt(scene\\,.2)"))
      context[:ffprobe_output] = result.stdout
    end
  end
end

module Video
  class RollupScenes
    include Interactor

    def before
      fail!(error: "Invalid ffprobe output") unless context[:ffprobe_output]
      fail!(error: "Invalid file path") unless context[:file_path] && File.exists?(file_path)

      context[:video] ||= FFMPEG::Movie.new(file_path)
    end

    def run
      ffprobe_info = CSV.parse(ffprobe_output, { col_sep: "|" })

      times = ffprobe_info.map do |row|
        Hash[row.map do |item|
          [item.split("=").first, item.split("=").last]
        end].fetch("pkt_pts_time", nil)
      end.compact

      context[:scene_times] = rollup_times(times)
    end

    private

    def rollup_times(times)
      last_time = 0
      rollup_times = []

      times.each do |time|
        if time.to_f - last_time.to_f > 0.5
          rollup_times << [last_time.to_d + 0.1, time.to_d - 0.1]
          last_time = time
        end
      end

      rollup_times << [last_time.to_d + 0.1, video.duration]
    end
  end
end

module Video
  class SplitVideoByScenes
    include Interactor

    def before
      fail!(error: "Invalid file path") unless context[:file_path] && File.exists?(file_path)
      fail!(error: "Invalid video file") unless FFMPEG::Movie.new(file_path).valid?
      fail!(error: "Invalid scene times") unless context[:scene_times] && scene_times.is_a?(Array)

      context[:directory] = File.dirname(file_path)
      context[:video_filename] = File.basename(file_path, ".*")
      context[:video_extension] = File.extname(file_path)
    end

    def run
      scene_times.each_with_index do |time, index|
        fast_seek_time = time[0] > 20 ? (((time[0] - 10).to_i / 10) * 10) : 0
        slow_seek_time = time[0] - fast_seek_time

        Command.run(%Q(ffmpeg -ss #{format_seconds(fast_seek_time)} -i #{file_path} -ss #{format_seconds(slow_seek_time)} -t #{format_seconds(time[1] - time[0])} -c:v libx264 -c:a libfaac #{directory}/#{video_filename}_#{index}#{video_extension}))
      end
    end

    private

    def format_seconds(seconds)
      Time.at(seconds.to_d).utc.strftime("%H:%M:%S.%6N")
    end
  end
end

module Video
  class SplitVideo
    include Interactor::Organizer

    organize Video::DetectScenes, Video::RollupScenes, Video::SplitVideoByScenes
  end
end