Found it!

I know you've already made some progress on this, but if you want to take a look, either for ideas or to use part of the code, here's the link:

If you have any questions, I'm happy to help. Good luck!

ok, it seems that what I need is this:

$parsed = get_string_between($contents, $parseBegin, $parseEnd);

    $contentParsed = $parseBegin . $parsed . $parseEnd;

    $handle = fopen($localFile, 'r+');
    $writer = fwrite($handle, $contentParsed);

    echo "Parsed content saved to " . $loc . "\n";
    return TRUE;

Let's check it

Hi guys!

Finally I found the solution! Easyer than I expected, the flv was a URL string so all I was needing was something like this:

preg_match_all('/url=(.*?;amp;)/sim', $content, $result, PREG_PATTERN_ORDER);
    $result = $result[1];

thank you!