Data extraction from /Filter /FlateDecode PDF stream in PHP

I can not decrypt the data from the stream like:

    56 0 obj 
    << /Length 1242 /Filter /FlateDecode >>
    stream
    x]êΩnƒ Ñ{ûbÀKq¬æ\âê¢....(whole binary is omitted)
    endstream
    endobj

I tried isolate the binary content (x]êΩnƒ Ñ{ûbÀKq¬æ\âê¢....) in a file and in a binary string. Decoding function gzinflate($encripted_data) sends me error of decoding, and I think it happens because encoded content in not "deflated" or so.

In PDF Reference v 1.7, (six edition), on a page 67, I found the description of /FlateDecode filter as: ...Decompresses data encoded using the zlib/deflate compression method, reproducing the original text or binary data

I need real raw solution, aka php function or/and algorithm what to do with this "\FlateDecoded" stream.

Thank You!