#!/usr/bin/env perl
 
 # Copyright (c) 2014 Nicolas George
 #
 # This file is part of FFmpeg.
 #
 # FFmpeg is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public License
 # as published by the Free Software Foundation; either
 # version 2.1 of the License, or (at your option) any later version.
 #
 # FFmpeg is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 
 =head1 NAME
 
 dvd2concat - create a concat script for a DVD title
 
 =head1 SYNOPSIS
 
 tools/dvd2concat I<path/to/dvd/structure> > I<file.concat>
 
 =head1 DESCRIPTION
 
 This script uses B<lsdvd> to produce concat script for a DVD title.
 The resulting script can be used to play the DVD using B<ffplay>, to
 transcode it using B<ffmpeg> or any other similar use.
 
 I<path/to/dvd/structure> is the path to the DVD structure hierarchy; it
 normally contains a directory named B<VIDEO_TS>. It must not be encrypted
 with CSS.
 

 I<file.concat> is the output file. It can be used as an input to ffmpeg.

 It will require the B<-safe 0> option.
 
 =cut
 
 use strict;
 use warnings;
 use Getopt::Long ":config" => "require_order";
 use Pod::Usage;
 
 my $title;
 
 GetOptions (
   "help|usage|?|h" => sub { pod2usage({ -verbose => 1, -exitval => 0 }) },
   "manpage|m"      => sub { pod2usage({ -verbose => 2, -exitval => 0 }) },
   "title|t=i"      => \$title,
 ) and @ARGV == 1 or pod2usage({ -verbose => 1, -exitval => 1 });
 my ($path) = @ARGV;
 
 my $lsdvd_message =
 "Make sure your lsdvd version has the two following patches applied:\n" .
 "http://sourceforge.net/p/lsdvd/feature-requests/1/\n" .
 "https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=603826\n";
 
 my $lsdvd = do {
   open my $l, "-|", "lsdvd", "-Op", "-x", $path
     or die "You need to install lsdvd for this script to work.\n$lsdvd_message";
   local $/;
   <$l>;
 };
 my %lsdvd = eval $lsdvd;
 die $@ if $@;
 
 if (!defined $title) {
   $title = $lsdvd{longest_track};
   warn "Using longest title $title\n";
 }
 my $track = $lsdvd{track}[$title - 1]
   or die "Title $title does not exist (1-", scalar(@{$lsdvd{track}}), ")\n";
 my $vts_base = sprintf "%s/VIDEO_TS/VTS_%02d_", $path, $track->{vts};
 my @frag;
 for my $i (1 .. 9) {
   my $file = sprintf "%s%d.VOB", $vts_base, $i;
   my $size = -s $file or last;
   push @frag, { file => $file, size => $size >> 11 };
 }
 
 my $concat = "ffconcat version 1.0\n";
 $concat .= "\nstream\nexact_stream_id 0x1E0\n";
 for my $audio (@{$track->{audio}}) {
   $concat .= "\nstream\nexact_stream_id " . $audio->{streamid} . "\n";
 }
 for my $subp (@{$track->{subp}}) {
   $concat .= "\nstream\nexact_stream_id " . $subp->{streamid} . "\n";
 }
 for my $cell (@{$track->{cell}}) {
   my $off = $cell->{first_sector};
   die "Your lsdvd version does not print cell sectors.\n$lsdvd_message"
     unless defined $off;
   my $size = $cell->{last_sector} + 1 - $cell->{first_sector};
 
   my $frag = 0;
   while ($frag < @frag) {
     last if $off < $frag[$frag]->{size};
     $off -= $frag[$frag++]->{size};
   }
   die "Cell beyond VOB data\n" unless $frag < @frag;
   my $cur_off = $off;
   my $cur_size = $size;
   my @files;
   while ($cur_size > $frag[$frag]->{size} - $cur_off) {
     push @files, $frag[$frag]->{file};
     $cur_size -= $frag[$frag]->{size} - $cur_off;
     $cur_off = 0;
     die "Cell end beyond VOB data\n" unless ++$frag < @frag;
   }
   push @files, $frag[$frag]->{file};
   my $file = @files == 1 ? $files[0] : "concat:" . join("|", @files);
   my $start = $off << 11;
   my $end = ($off + $size) << 11;
   $file = "subfile,,start,${start},end,${end},,:$file";
 
   my $dur = int(1000 * $cell->{length});
   $concat .= sprintf "\nfile '%s'\nduration %02d:%02d:%02d.%03d\n", $file,
     int($dur / 3600000), int($dur / 60000) % 60, int($dur / 1000) % 60,
     $dur % 1000;
 }
 
 print $concat;