FFmpeg config for scale video size

gistfile1.PL

#!/usr/bin/perl
use strict;

my @SOURCE = (2000, 1500);
my @FORMAT = (1920, 1080);
my $K      = '16x9';

my @check = check_video($SOURCE[0], $SOURCE[1], $FORMAT[0], $FORMAT[1], $K);

my $x = $check[1] / 2;
my $y = $check[0] / 2;
my $s = join 'x', $FORMAT[0]-$check[1], $FORMAT[1]-$check[0];

print qq{-s $s -padtop $y -padbottom $y -padleft $x -padright $x};

sub check_video($$$$;$) {
	my($w, $h, $w2, $h2, $x2) = @_;
	{
		$w == 848 and $h == 478 and $h -= 1; # 848x477 - fuck :)
	}
	my $round = sub {
		return $_[0] unless $x2 eq '16x9';
		
		my $max = my $min = int shift;
		$max += 1, $min -= 1 while $max % 4 != 0 && $min % 4 != 0;
		
		return $max % 4 == 0 ? $max : $min; # max
	};
	my $calc; $calc = {
		'0' => sub {
			return (0, 0);
		},
		'x' => sub { # leftright
			return  $_ > $w2 ? $calc->{'y'}->(@_) : (0, $round->($w2 - $_))
				for map { sprintf "%.0f", $_ } $_[1]*$w/$h; # $w/$h = x/$h2
		},
		'y' => sub { # topbot
			return  $_ > $h2 ? $calc->{'x'}->(@_) : ($round->($h2 - $_), 0)
				for map { sprintf "%.0f", $_ } $_[0]*$h/$w; # $w/$h = $w2/y
		},
	};
	
	my $k = {'16x9' => 9/16, '4x3' => 3/4}->{$x2} * $w || return $calc->{'0'}->();
	
	return
		($h < $k) # topbot
	 ?
		$calc->{'y'}->($w2, $h2)
	 :
		($h > $k) # leftright
	 ?
		$calc->{'x'}->($w2, $h2)
	 :
		$calc->{'0'}->();
}