#! perl -sw
use strict;
use bytes; 

open IN,  '< :raw', $ARGV[ 0 ] or die "$ARGV[ 0 ] : $!";
open OUT, '> :raw', $ARGV[ 1 ] or die "$ARGV[ 1 ] : $!";

## Grab a double buffer load first time so we can check & correct alignment
local $/ = \768; 

my $buf = <IN>; ## Read two frames worth

## Check alignment. Assumes the xf4 .191 xf4 is unique per frame?
$buf =~ m[(\xF4.{191}\xF4)];

## Record the offset to the first frame
my $offset = $-[0];

## If there was an offset to the first match
if( $offset != 0 ) {
	## Chop off the leading junk
	substr( $buf, 0, $offset, '' );
	
	## Top up the buffer to two full frames
	read( IN, $buf, $offset, 768 - $offset );
	
	warn "$offset bytes discarded from front of file.";
}

## Process the first two whole frames
print OUT unpack 'x2 a190 x2 a58 x132' x 2, $buf

## Now process as before
local $/ = \384; ## Read file in 384 byte chunks.


while( <IN> ) {
    print OUT unpack 'x2 a190 x2 a58', $_;
}

close IN;
close OUT;