PHP - JSON com acentos

Ótima função que achei para resolver os problemas com acentos em strings JSON..

    function raw_json_encode($input) {        return preg_replace_callback(          '/\\\\u([0-9a-zA-Z]{4})/',          function ($matches) {              return mb_convert_encoding(pack('H*',$matches[1]),'UTF-8','UTF-16');          },          json_encode($input)      );    }

Link original: 

http://stackoverflow.com/questions/16498286/why-does-the-php-json-encode-function-convert-utf-8-strings-to-hexadecimal-entit/16498714#16498714 

André Emerich