require 'open-uri' def raw_dir(size)  sprintf("raw/%s", size)end def raw_files(size)  (5208..5280).collect {|n| sprintf("raw/%s/big_buck_bunny_%05d.png", size, n)}end # 640x360directory raw_dir("640x360") rule %r(raw/640x360/big_buck_bunny_[0-9]+\.png) => raw_dir("640x360") do |t|  url = sprintf("http://media.xiph.org/BBB/BBB-360-png/%s", t.name.pathmap("%f"))  puts "Grabbing #{url}"  open(url) do |s|    IO.copy_stream(s, t.name)  endend file "test_640x360.h264" => raw_files("640x360") do |f|  sh "ffmpeg -y -start_number 5208 -i raw/640x360/big_buck_bunny_%05d.png -pix_fmt yuv420p -c:v libx264 -x264-params keyint=40 -profile:v baseline -f rawvideo test_640x360.h264"end # 1920x1080directory raw_dir("1920x1080") rule %r(raw/1920x1080/big_buck_bunny_[0-9]+\.png) => raw_dir("1920x1080") do |t|  url = sprintf("http://media.xiph.org/BBB/BBB-1080-png/%s", t.name.pathmap("%f"))  puts "Grabbing #{url}"  open(url) do |s|    IO.copy_stream(s, t.name)  endend file "test_1920x1080.h264" => raw_files("1920x1080") do |f|  sh "ffmpeg -y -start_number 5208 -i raw/1920x1080/big_buck_bunny_%05d.png -pix_fmt yuv420p -c:v libx264 -x264-params keyint=40 -profile:v baseline -f rawvideo test_1920x1080.h264"end desc "Generate encoded test h264 files."task :generate_test_data => ["test_640x360.h264", "test_1920x1080.h264"]  rule ".yuv" => ".h264" do |t|  sh "ffmpeg -y -i #{t.source} -c:v rawvideo -pix_fmt yuv420p #{t.name}"end desc "Generate decoded yuv test data using ffmpeg. This data is used when comparing decoded output with a known-good sample."task :generate_output_data => ["test_640x360.yuv", "test_1920x1080.yuv"] task :clean do  FileUtils.rm_rf "raw"  FileUtils.rm_f "test_640x360.h264"  FileUtils.rm_f "test_1920x1080.h264"  FileUtils.rm_f "test_640x360.yuv"  FileUtils.rm_f "test_1920x1080.yuv"end task :default => [:generate_test_data]