So i came across this handy scripts.

As part of some new offensive ;), or maybe just privacy concerns for the user.
Flash now right after beginning a FLV download
deletes the file from the /tmp directory

As it still has a lock on the file descriptor, it disappears right after the flash player closes.

Let the video finish streaming and then run this script
It will save the deleted flv videos with open file descriptors into the folder where you have run the script.

#!/usr/bin/perl
# Filename:	flashcache
# Author:	David Ljung Madison <DaveSource.com>
# See License:	http://MarginalHacks.com/License/
# Description:	Copy flash files in your browsers cache
# Dependencies:	Unix command 'lsof'
use strict;

##################################################
# Setup the variables
##################################################
my $PROGNAME = $0; $PROGNAME =~ s|.*/||;

my $LSOF = 'lsof';

my $FIND = 'flash';	# Find flash files
my $POST = 'flv';	# Postfix to save to

# Where we save files
#   %f is $FIND
#   %d is the next available number
#   %p is .$POST
my $DEST = "found%f.%d%p";

##################################################
# Usage
##################################################
sub fatal {
	foreach my $msg (@_) { print STDERR "[$PROGNAME] ERROR:  $msg\n"; }
	exit(-1);
}

sub usage {
	foreach my $msg (@_) { print STDERR "ERROR:  $msg\n"; }
	print STDERR <<USAGE;

Usage:\t$PROGNAME [-d]
  Copies deleted flash files currently open in your browser's cache
  -d             Set debug mode
  -find <str>    What to search for  [default $FIND]
  -post <str>    Postfix for saving files [default $POST]
  -dest <str>    Or just specify full destination [default $DEST]
                 (see the script for meanings of %f, %d, %p)

USAGE
	exit -1;
}

sub parseArgs {
	usage("You need to be on a system that uses /proc") unless -d '/proc';

	my $opt = {
		find => $FIND,
		post => $POST,
		dest => $DEST,
	};
	while (my $arg=shift(@ARGV)) {
		if ($arg =~ /^-h$/) { usage(); }
		if ($arg =~ /^-d$/) { $MAIN::DEBUG=1; next; }
		if ($arg =~ /^-find$/) { $opt->{find} = shift(@ARGV); next; }
		if ($arg =~ /^-post$/) { $opt->{post} = shift(@ARGV); next; }
		if ($arg =~ /^-dest$/) { $opt->{dest} = shift(@ARGV); next; }
		if ($arg =~ /^-/) { usage("Unknown option: $arg"); }
		usage("Too many files specified [$arg and $opt->{file}]") if $opt->{file};
	}

	usage("You need to specify a destination with -dest")
		unless $opt->{dest};
	
	usage("You need to specify something to search for with -find")
		unless $opt->{find};
	
	$opt;
}

sub debug {
	return unless $MAIN::DEBUG;
	foreach my $msg (@_) { print STDERR "[$PROGNAME] $msg\n"; }
}

##################################################
# Main code
##################################################
sub findFiles {
	my ($opt) = @_;
	my @found;
	# 'lsof /'  (The '/' just does files, no sockets, and is faster)
	open(LSOF,"$LSOF /|") || usage("Can't run [$LSOF]");
	while (<LSOF>) {
		next unless /delete/i;
		next unless /\Q$opt->{find}\E/i;
		chomp;
		# procname  pid  user   fd
		usage("Found it, can't parse it [$_]")
			unless /^\S+\s+(\d+)\s+\S+\s+(\d+)/;
		push(@found, [$1,$2]);
	}
	usage("Couldn't find any deleted cached $opt->{find} files")
		unless @found;
	@found;
}

sub procPath {
	my ($pid,$fd) = @_;
	my $path = "/proc/$pid";
	usage("Couldn't find $path") unless -d $path;
	$path .= '/fd';
	usage("Couldn't find $path") unless -d $path;
	$path .= "/$fd";
	usage("Couldn't read $path") unless -e $path;
	$path;
}

sub destPath {
	my ($opt) = @_;
	my $p = $opt->{dest};
	$p =~ s/%f/\Q$opt->{find}\E/g;
	$p =~ s/%p/.\Q$opt->{post}\E/g;
	my $num = 0;
	my $path;
	do {
		$path = $p;  $num++;
		$path =~ s/%d/$num/g;
	} until ! -f $path;
	$path;
}

sub main {
	my $opt = parseArgs();
	
	my @found = findFiles($opt);
	foreach my $found ( @found ) {
		my $src = procPath(@$found);
		my $dest = destPath($opt);
		print "$src -> $dest\n";
		system("/bin/cp",$src,$dest);
	}
}
main();