Unable to access library function in codeigniter - php

Question

I am noob in codeigniter. I used an external class file for getting the length of an audio file. I put the file in application/libarary directory. After googling and reading documentation I tried two things for accessing the libarary function which I have mentioned under the codeigniter problem.
Working Demo from the External Library File
require ('classAudioFile.php');
$filename = "40f11852c2314cdf1d06308f07de3b1c.mp3";
$AF = new AudioFile;
$AF->loadFile($filename);
echo $AF->wave_length;
CodeIgniter Problem
$filename = "./uploads/audio_files/347f21502e9b27fac4707b07c3c15eb7.mp3";
$CI =& get_instance();
$CI->load->library('AudioFile');
$CI->AudioFile->loadFile($filename);
$filename = "./uploads/audio_files/347f21502e9b27fac4707b07c3c15eb7.mp3";
$this->load->library('AudioFile');
$this->AudioFile->loadFile($filename);
I am getting Call to a member function loadFile() on a non-object in D:\wamp\www\webcartz\application\modules\playlist\controllers\admin.php on line 149 this is the actuall error.. can any body please help. I tried to call it in both Controller and View file.

Answer 1

to normalize everything try the following:
the AudioFile.php you put in the library folder, make the file name all lower case, like audiofile.php. if it is called classAudioFile.php, rename it to simply audiofile.php
check that there is a class AudioFile in audiofile.php.
change the AudioFile in the load->library to all lowercase
change the AudioFile in the $this->AudioFile-> to all lowercase
if it still does not work change the name of the class (not the file) to Audiofile, capital A, lower case f.
Also, there should be an default - no parameter constructor in the class Audiofile. like this:
public function __construct()
{
// you can put some code here if you want
}