The Media Transfer Protocol (MTP) is a USB class protocol which can be used to transfer files to and from storage devices. MTP is an official extension of the Picture Transfer Protocol (PTP) designed to allow digital cameras to exchange image files with a computer. MTP extends this by adding support for all types of files.
Application Samples emUSB-Host MTP
The emUSB-Host MTP implementation works out of the box with most vendors' MTP device implementations. Functionality has been confirmed with a multitude of Android distributions, Windows phones and other MTP devices.
For more technical details about MTP and PTP follow this link.