#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long qw(GetOptions);

my $help = 0;
GetOptions("help" => \$help) or help();
help() if $help;

my $file = $ARGV[0] || help();
my $time = $ARGV[1] || help();

unless (-e $file) {
    print "Can't find file '$file'\n";
    help();
}

unless ($file =~ /\.mp4$/) {
    print "That's not an mp4 file. Refusing to trim it.\n";
    help();
}

$file =~ s/\.mp4$//;
my $orig = $file . ".mp4";
my $trimmed = $file . "_edit.mp4";
my $bak = $file . "_bak.mp4";

# ok, now the nasty work
qx/ffmpeg -noaccurate_seek -ss $time -i $orig -c copy $trimmed/;
qx/mv $orig $bak/;
qx/mv $trimmed $orig/;

sub help {
    print "\nUsage: $0 FILE TIME\n";
    print "Eg: $0 openofficeT1514.mp4 234.44\n";
    exit();
}