flv2mp4.rb

#!/usr/bin/ruby -Kn

fn=ARGV[0].to_s
bn=fn.sub(/\.flv$/,'')
vn="#{$$}_track1.h264"
an="#{$$}_track2.aac"
out="#{bn}.mp4"
fps=ARGV[1]

if not File.exists? fn
  puts "#{fn} not found"
  exit
end

if File.exists? out
  puts "#{out} already exists"
  exit
end

if !fps
  if /\x09framerate\x00(.{8})/=~IO.read(fn, 1024)
    fps = $1.unpack("G")[0]
  else
    puts "fps read error(#{Regexp.last_match})"
    exit
  end
end

if /[0-9]{2}(\.[0-9]+)?/ !~ fps.to_s
  puts "invalid fps(#{fps})"
  exit
end

system("ffmpeg","-i",fn,"-vcodec","copy","-vbsf","h264_mp4toannexb","-an",vn)
system("ffmpeg","-i",fn,"-vn","-acodec","copy",an)
system("MP4Box","-add",vn,"-add",an,"-fps",fps.to_s,out)
File.unlink(vn,an)

__END__
ffmpeg -i "$fn" -vcodec copy -vbsf h264_mp4toannexb -an "$vn"
ffmpeg -i "$fn" -vn -acodec copy "$an"
MP4Box -add "$vn" -add "$an" -fps $fps "$out"
rm -v "$vn" "$an"