Here is the code I'm using and for a 1 gig file this takes a few hours.

Pardon me for saying so, but I am not surprised.

Not only are you unpacking the data to asciized binary, you then go on to split that into an array of digits.

Then use a loop to go through that array one byte at a time looking for pairs of bytes that match '00' so that you can replace them with '11', or '11' and replace those with '00'.

All this could be done with a couple of regex.

Replacing this:

while (<IN>) { 
    my $bits = unpack("b*", $_);
    @array = split(//, $bits);
    foreach $value (@array) { 
        $y++;
        $tmp = $tmp . $value;
        if ($y == 2) { 
            if ($tmp =~ /00/) { 
                $tmp = '11';
            } elsif ($tmp =~ /11/) { 
                $tmp = '00';
            } 
            print OUT $tmp;
            $y = 0;
            $tmp = '';
        } 
    } 
}
[download]

with this:

while (<IN>) { 
    my $bits = unpack("b*", $_);
    $bits =~ s[(00|11)][ $1 eq '00' ? '11' : '00']ge;
    print OUT $bits;
}
[download]

should do (untested) the same thing and will run very much more quickly.

Do I understand the logic of this code correctly?

$/ = \7680;
my $x = 0;

#I LEFT THE OUTPUT AS ASCII-IZED BINARY AT THIS POINT #THUS THE LARGE 
+INCREASE IN FILE SIZE 
open IN, "$tmp2";
open OUT, >$tmp3";
while (<IN>) { 
    $_ =~ s/^.*(11111011000010001111011100010000)/$1/ if $x == 0;
    $x = 1;
    print OUT pack("b*", $_);
} 

close IN;
close OUT;
[download]

You are checking the first record only for the first occurance of the sync pattern, and then discarding anything that preceeds it?

Ie. If the first record contains a partial frame, then throw it away and so sync the rest of the file?

If so, then the following code should be a complete replacement and run in a fraction of the time. The output file "tmp2" will be the final file you are after without creating the 9 GB intermediate.

Let me know if it works please. Also how long it takes. There are other thing that could be code to speed this up I think, but if the new runtime is acceptable, they may not be worth the extra effort.

die "USAGE: $0 input\n" if scalar(@ARGV) < 1;
$| = 1;
$/ = \960;

open IN, "$ARGV0" or die "$ARGV0 : $!";
open OUT, ">tmp2";

my $y = 0;
my $value = '';

while (<IN>) { 
    my $bits = unpack("b*", $_);
    
    ## Replace '00' with '11' and vice versa
    $bits =~ s[(00|11)][ $1 eq '00' ? '11' : '00']ge;
    
    ## Discard any partial fraem from the front of the file.
    $bits =~ s/^(.*)(?=11111011000010001111011100010000)// if $. == 1;
    
    print OUT pack 'b*', $bits;
} 

close IN;
close OUT;
[download]

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