As promised, here is the script I use to change a set of AVI files
into a DVD disc image. It uses Rake and rmovie along with a whole
bunch of Linux utilities, and doesn’t require any aditional input from
the user beyond having the AVI files in the same directory as the
rakefile.
It goes through the following steps:
For each AVI file in the current directory:
-
Use transcode to convert it into a M2V video file and an AC3 audio
track. -
Use mplex to join these two files into a MPG file.
-
Use dvdauthor to convert the MPGs to a DVD file structure.
-
Use mkisofs to change the DVD file structure into a ISO image file,
ready for burning. -
Clean up by deleting everything except the AVI files, the ISO image
and the MPG files (which take the longest time to create, and are
useful if something goes wrong and I have to start over :)).
It’s probably too specific to be worth posting to Rubyforge or one of
its equivalents, so I’m sending it here in case someone else finds it
useful. There’s probably a lot I can improve here, so I’d be thankful
to hear any suggestions or criticisms.
=====================================================
require ‘rubygems’
require ‘rake’
require ‘rake/clean’
require ‘rmovie’
OUTPUT_RATIO = 1.6
SOURCE_FILES = FileList[’.avi’]
DESTINATION_FILES = SOURCE_FILES.gsub(‘avi’,‘mpg’)
CLEAN.include(’.xml’,’*.cfg’,‘DVD’)
def adjust_clip(x, y)
clip_size = -1* (((x.to_i / OUTPUT_RATIO) - y.to_i) / 2).abs
int_clip = clip_size.to_i
return int_clip if int_clip % 2 == 0
return int_clip - 1
end
def transcode(filename)
nome, extensao = filename.split(’.’)
movie = RMovie::Movie.new(filename)
clip_size = adjust_clip(movie.frame_width, movie.frame_height)
bit_rate = ( movie.bit_rate / 1000 ).ceil
ratio = movie.frame_width.to_f / movie.frame_height.to_f
if ratio == ( 4.0 / 3.0 )
aspect = 2
elsif ratio == ( 16.0 / 9.0 )
aspect = 3
end
sh <<-FIM
transcode -i "#{filename}" -y ffmpeg --export_prof dvd-ntsc
–export_asr #{aspect} --pre_clip=#{clip_size},#{clip_size} -w
#{bit_rate} -o #{nome} -D0 -b224 -N 0x2000 -s2 -m #{nome}.ac3 -J
modfps=clonetype=3 --export_fps 29.97
FIM
end
def mplex(basename)
nome = basename.split(’.’)[0]
sh “mplex -f 8 -o #{nome}.mpg #{nome}.m2v #{nome}.ac3”
end
def write_xml_header(xml)
xml.write <<-HEADER
HEADER
end
def write_xml_footer(xml)
xml.write <<-FOOTER
FOOTER
end
rule ‘.mpg’ => [’.avi’] do |t|
nome = t.name.split(’.’)[0]
transcode(t.prerequisites[0])
mplex( nome )
rm “#{nome}.m2v”
rm “#{nome}.ac3”
end
rule ‘.mpg’ => [’.m2v’, ‘ac3’] do |t|
nome = t.name.split(’.’)[0]
mplex( nome )
rm “#{nome}.m2v”
rm “#{nome}.ac3”
end
file ‘ffmpeg.cfg’ do |t|
File.open(t.name, ‘w’) do |cfg|
cfg.write <<-FIM
[mpeg2video]
vrc_minrate=0
vrc_maxrate = 5000
vrc_buf_size = 1792
FIM
end
puts ‘ffmpeg.cfg escrito’
end
file ‘dvdauthor.xml’ => DESTINATION_FILES do |t|
File.open(t.name, ‘w’) do |xml|
write_xml_header(xml)
DESTINATION_FILES.sort.each do |file|
xml.write <<-LINHA
LINHA
end
write_xml_footer(xml)
end
end
file ‘DVD’ => [‘dvdauthor.xml’] do |t|
sh “dvdauthor -o #{t.name} -x #{t.prerequisites[0]}”
end
task ‘dvd.iso’ => [‘DVD’] do |t|
sh “mkisofs -o #{t.name} -dvd-video #{t.prerequisites[0]}”
end
task :default =>[‘ffmpeg.cfg’,‘dvd.iso’, :clean]
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