Default sorting option

default-sorting.php

<?php

/**
*
* Sorts media on page load accoeging to perameters passed
* Use this function when rtmedia-sorting plugin is active
*
*/
function rtmedia_custom_order_by( $order_by ) {
	// if it's not json data
	if ( ! isset( $_REQUEST['json'] ) ) {
		// 'media_id ASC'; // for Upload Date (ASC)
		// 'media_id DESC'; // for Upload Date (DESC)
		// 'file_size ASC'; // for Size (ASC)
		// 'file_size DESC'; // for Size (DESC)
		// 'media_title ASC'; // for Title (ASC)
		$order_by = 'media_title ASC';
	}
	return $order_by;
}
add_filter( 'rtmedia_model_order_by', 'rtmedia_custom_order_by' );

/**
*
* Sets parameter in hidden field for order by
*
*/
function rtmedia_upload_hf_sort_by( $sort_by ) {
	// if it's not json data
	if ( ! isset( $_REQUEST['json'] ) ) {
		// 'title': if Title (ASC OR DESC)
		// 'date' : if Upload date (ASC OR DESC)
		// 'size' : if file size (ASC OR DESC)
		$sort_by = 'title';
	}
	return $sort_by;
}
add_filter( 'rt_upload_hf_sort_by', 'rtmedia_upload_hf_sort_by' );

/**
*
* Sets parameter in hidden field for sort order
*
*/
function rtmedia_upload_hf_sort_order( $sort_order ) {
	// if it's not json data
	if ( ! isset( $_REQUEST['json'] ) ) {
		// 'desc' : if title, size or date DESC
		// 'asc'  : if title, size or date ASC
		$sort_order = 'asc';
	}
	return $sort_order;
}
add_filter( 'rt_upload_hf_sort_order', 'rtmedia_upload_hf_sort_order' );

?>