#!/usr/bin/perl

my $i = 0;
my $ls  = `ls -1v *.png`;
my @lines = split('\n', $ls);
my $pwd = `pwd`;
chomp $pwd;
$pwd .= '/';

system('mkdir', 'tmp');

for my $line (@lines) {
  chomp $line;
  system('ln', '-s', $pwd . $line, sprintf('./tmp/frame_%05d.png', $i));
  $i += 1;
}

system("ffmpeg",
  "-i", "./tmp/frame_%05d.png",
  "-y", "-c:v", "libx264", "-vf", "fps=25", "-pix_fmt", "yuv420p",
  "-s", "456x256",
  $tag . ".mp4"
);

END {
  system('rm', '-rf', 'tmp');
}