PrMTP is an MTP (Media Transfer Protocol) stack enabling portable devices such as digital cameras, mobile phones, or portable music/movie players to connect with Windows PCs for transferring media such as music, movies, and still images in both directions.

Along with PrMTP, eSOL offers a middleware package including PrFILE2, PrFILE2 exFATPrUSB Device, and PrUSB Host for a complete development platform for MTP compatible devices.

MTP applications

What is MTP?

Already Supported by Windows

MTP is supported by Windows XP or later through Windows Media Player 10 or above. An MTP-compatible device can exchange data with a Windows PC easily and quickly without installing any special software or driver. In the future, Windows-compatible devices may be expected to require MTP.

Supports copyright protection technology (DRM)

MTP supports copyright protection management technology through the DRM (digital rights management) in Windows Media Audio (WMA). Widely used by many online music stores, this technology secures and protects digital content, including music, movies, and books, from illegal reproduction.

Developed from PTP - MTP's advantages over PTP

MTP is a standard developed by Microsoft and based on PTP, the image transfer protocol. Compared to PTP, MTP can handle much larger files, or multiple files at once. Another advantage of MTP is the inherent support for various types of media, such as still images, movies, and music, with a single protocol

Any file system can be implemented

Any file system (even non-FAT) can be implemented with MTP because MTP does not depend on the file system type. Differentiate your product by implementing a reliable and fast file system.

Control a portable device from a computer

MTP can be used to control a portable device from a personal computer. You can operate a device remotely, monitor device events, or configure a device. Such features are not available with a Mass Storage Class USB device.

AutoSync feature

MTP can transfer content automatically when a device is connected, without any dragging and dropping or using any application. Preset the contents to transfer with Windows Media Player.

Automatic notification

MTP has a feature to automatically notify the PC regarding a device's files and features. Windows Media Player can automatically convert or compress media content, or start transferring files when a device is connected.

Synchronization of file properties with a PC

MTP can synchronize file properties between a portable device and a PC.

Configuration is easy

Just like a Mass Storage Class-based USB device,an MTP device is automatically recognized as a connected storage device by the PC, so configuring various settings is easy.

PrMTP Initiator and Responder

The protocol is implemented for use across USB. The host connecting to an MTP device is called an PrMTP Initiator, whereas the device itself is an PrMTP Responder.

The initiator 'initiates' communication by sending a command to the responder. The responder processes the command and sends back an appropriate response. Examples of the initiator and responder are home video/audio equipment and car audio players, and portable audio players and digital still cameras, respectively. On Microsoft Windows, PrMTP is supported in Microsoft Windows XP if Windows Media Player 10 or later versions are installed.

PrMTP Overview

PrMTP Responder

PrMTP Responder is the MTP responder-compliant protocol geared towards portable consumer electronics.

  • Aimed at portable audio players or media players
  • Transparent access to a file system from the application, since the object storage function (object store) is virtualized
  • Compatible with Windows Media Player 10
  • Support for Windows Media Digital Rights Management (WMDRM) - a license from Microsoft must be acquired
  • File system agnostic (default supported file system is FAT)
  • Full source code
PrMTP architecture diagram

MTP/PTP core protocol
    • Creates/analyzes MTP and PTP packets
    • Manages sessions with the initiator
    Object Store
    • Stores media files (still images, audio, video)
    • Is designed to handle many large-sized files very efficiently
    Transport Layer
    • Transfers the packets
    • Has an abstraction layer to handle different transport methods
    • Uses USB as the standard transport method for MTP/PTP
    • Implemented as an MTP class driver based on Still Image Capture Device Class

    PrMTP Initiator

    PrMTP Initiator is the MTP initiator-compliant protocol.

    • imed at audio/video systems and in-car entertainment devices
    • Supports USB digital media streaming, so that you can playback WMDRM-protected files via streaming
    • Supports both one-wire and two-wire playback
      • One-wire playback essentially stream encoded content over a protected USB line to a one-wire enabled USB host and transmit digitally.
      • Two-wire playback use an MTP initiator to serve as a command and control interface to the MTP responder. Simple commands, such as next track or previous track, allow the initiator to effectively navigate content on a responder player. In the two-wire case, audio is played in analog format.
    • Designed to be independent of OS, CPU and file systems
    • Supports PlayForSure devices
    • Full source code
    • T-Kernel, ITRON and various OSes are supported by default
    Merits of MTP Initiator

    As more MTP-compatible devices are expected to be introduced into the market, the need to play back video/audio via streaming to other devices such as car audio or home audio systems will rise. This can be achieved by implementing the USB digital media streaming functionality offered by MTP Initiator. Eliminating the need for the analog-to-digital conversion and adding the ability to transfer content digitally provides better audio/video quality over analog playback. You can play back WMDRM-protected data. Also, from the initiator devices you can conduct operations such as playback, fast-forward, rewind, pause, and stop.

    Building Block Architecture

    We offer various middleware packages, file systems (PrFILE2), USB stacks (PrUSB), etc., ready for use with PrMTP Initiator.

    Support and Maintenance

    We offer the following services for PrMTP:

    • Technical support via email
    • Product updates

    We also offer professional services to tailor PrMTP to a different target environment, including compiler support, RTOS support, a board support package, and even support for a new processor.

    Operating environment

    PrMTP requires an RTOS, file system, and USB (USB Device for the responder, and USB Host for the initiator). By default, eT-KernelPrFILE2, PrFILE2 exFATPrUSB Host and PrUSB Device from eSOL supports PrMTP.

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