Printing byte as 2 Hex characters

[ShiningPerl]

I am studying video and other kind of files that deals with packed data. I want to break down a flv file into its byte and printing on the screen but I face alot of difficulties. My desired output to print 0b11110000 as 0xF0 but all I got was 0. Is there something wrong with the print format?

#! /usr/bin/perl

$data_file="1.flv";
open (FILE, $data_file) or die ("Could not open file!"); 

my $len=0;

while($len!=7){
read (FILE, $buffer, 1);

print "Char Format: ";
print "$buffer ";

print "Hex Format: ";
printf ("%lX ", $buffer);

print " Test Print Format";
$test=255;
print " ".$test." ";
printf ("%lX", $test);

print "\n";
$len++;
}

print "\n=====End of Script=====";

close(FILE);