Codeigniter large video is uploading fine but audio is not uploading - php

Question

In my controller I am trying to add audio and video, I changed my php.ini file and extended max_file_size, post_size etc.
When I upload a video of 25M, it is successfully getting upload
but when I try to upload an audio file of 4MB then it got failed.
Then again I tried to upload an audio file of 433KB, it got successfully upload.
HERE is my code below and I am not able to find what is the reason its not working
if(!empty($_FILES['audio_upload']['name'])){
$config['upload_path'] = 'uploads/';
$config['allowed_types'] = 'mp3|wmv|mp4';
$config['max_size'] = '0';
$config['file_name'] = $this->input->post('sub_category_name');
//Load upload library and initialize configuration
$this->load->library('upload',$config);
$this->upload->initialize($config);
if($this->upload->do_upload('audio_upload')){
$uploadData = $this->upload->data();
$audio_upload = $uploadData['file_name'];
}
else{
$audio_upload = '';
}
}
if( !empty($audio_upload)){
$media_link = 'uploads/'.$audio_upload;
}
else{
$media_link = $this->input->post('media_link');
}
//**************************************END
//**************************************Video Upload
if(!empty($_FILES['video_upload']['name'])){
$config['upload_path'] = 'uploads/';
$config['allowed_types'] = 'mp3|wmv|mp4';
$config['max_size'] = '0';
$config['file_name'] = $this->input->post('sub_category_name');
//Load upload library and initialize configuration
$this->load->library('upload',$config);
$this->upload->initialize($config);
if($this->upload->do_upload('video_upload')){
$uploadData = $this->upload->data();
$video_upload = $uploadData['file_name'];
}
else{
$video_upload = '';
}
}
if( !empty($video_upload)){
$video_link = 'uploads/'.$video_upload;
}
else{
$video_link = $this->input->post('media_link');
}