extract-video-parts

#!/usr/bin/perl

use strict;
use warnings;
use File::Basename;

my $prefix = 'part';
my $suffix = 'mp4';

die "Usage: ".basename($0)." file start1-end1 ...\n" unless @ARGV > 1;

my $video = shift;
die "No file $video.\n" unless -f $video;

my @times = ();
for my $arg (@ARGV) {
  $arg =~ s/\s+//g;
  if ($arg =~ /^(\d+):(\d+)-(\d+):(\d+)$/) {
    my $start_seconds = 60*$1 + $2;
    my $end_seconds = 60*$3 + $4;
    my $duration = $end_seconds - $start_seconds;
    push @times, $start_seconds;
    push @times, $duration;
  } else {
    die "Illegal time specification '$arg', format must be M:SS-M:SS.\n";
  }
}

my $i = 1;
my @partfiles;
while (@times) {
  my $start_seconds = shift @times;
  my $duration = shift @times;
  my @cmd = ('ffmpeg');
  push @cmd, '-ss', $start_seconds;
  push @cmd, '-i', $video;
  #push @cmd, '-c', 'copy';
  push @cmd, '-t', $duration;
  my $partfile = sprintf "%s%0*i.%s", $prefix, length(@times)/2, $i, $suffix;
  push @cmd, '-y', $partfile;
  push @partfiles, $partfile;
  print "Part $i (start $start_seconds, duration $duration) ...\n";
  #system(@cmd);
  ++$i;
}

print "Created part files: ".join(' ', @partfiles), "\n";