Several methods to increase file upload limit in Wordpress.
@ini_set( 'upload_max_size' , '64M' );
@ini_set( 'post_max_size', '64M');
@ini_set( 'max_execution_time', '300' );
upload_max_filesize = 64M
post_max_size = 64M
max_execution_time = 300
php_value upload_max_filesize 64M
php_value post_max_size 64M
php_value max_execution_time 300
php_value max_input_time 300