The Guidelines for Picture and Video Import in Windows 7 white paper provides information about the picture and video import feature in Windows 7. The white paper includes guidelines for OEMs designing digital cameras and camera-equipped portable devices compatible with and optimized for Windows 7. The following screenshot shows a Device Stage experience for a cellular phone that supports photo and/or video import. The Windows 7 inbox photo import task appears as one of the many tasks that an end-user can interact with that phone.

This white paper describes the types of devices that are supported in Windows 7 for the picture and video import feature. In addition, this paper discusses device requirements and recommended features for optimal performance during the import of pictures and video from the device.

Topics Covered

Some of the topics covered in this white paper are:

• The supported device classes
• The supported picture and video formats
• Device requirements and recommendations:
  • Preventing re-import of videos synchronized with Windows Media Player by implementing Sync ID device property
  • Improving import performance by implementing the Hints Device Service
  • Enabling a determinate-style progress bar like the one shown below, instead of the default indeterminate progress bar

More Resources

You can find this whitepaper and more related Windows Portable Devices information (for both application and device development) on the Windows Hardware Developer Central portal.

This posting is provided "AS IS" with no warranties and confers no rights.

The Platform Update for Windows Vista features a set of runtime libraries which add support for new technologies making it easier for developers to develop for Windows 7 and Windows Vista without impacting their users.

Features

The WPD update adds WPD and MTP Device Services and MTP over Bluetooth features to Windows Vista. The following table identifies the WPD features supported for Windows 7, for Windows Vista, and for Windows Vista with the Platform Update for Windows Vista installed.

Availability and installation

The Platform Update for Windows Vista is available for free via Windows Update, Windows Server Update Services and the Microsoft Download Center. Customers running Windows Vista Service Pack 2 with “recommended settings” enabled for Windows Update will automatically receive the update without additional action. The update is also available as a free download on the Microsoft Download Center.

Additional notes about the Platform Update for Windows Vista

All the updated technologies in the Platform Update for Windows Vista are already included in Windows 7. The Platform Update for Windows Vista is not required for Windows 7.

To apply the Platform Update for Windows Vista, you must have Windows Vista Service Pack 2 installed.

More information

For specific details about the Platform Update for Windows Vista, click here.

For more information about MTP Device Services, check out the Introducing Device Services entry.

For more information about MTP transports such as USB, IP, and Bluetooth, check out the MTP Over Various Transports entry.

This posting is provided "AS IS" with no warranties and confers no rights.

The MTP Simulator implements all MTP device capabilities, object properties, and operations that are based on the MTP Specification along with the major features in Windows 7. Additionally, the MTP Simulator also supports Device Stage and loading customizable device profiles.

For transport support, the MTP Simulator runs on multiple transport options such as USB, Software-Simulated USB (SoftSim), Bluetooth, and IP. Last, but not the least, the MTP Simulator runs on both Windows Vista and Windows 7.

Where to get the MTP Simulator

The MTP Simulator is publicly available as part of the Windows 7 Portable Device Enabling Kit for MTP (DEK). The kit also includes support documentation for the MTP Simulator and the MTP Specification Version 1.0 and MTP Device Services for Windows. Included in the DEK is the MTP Device Simulator User Guide which provides a detailed description of the MTP Simulator.

Installing the MTP Simulator

The MTP Device Simulator is installed as part of the Windows 7 Portable Device Enabling Kit for MTP (DEK). Before running the simulator for the first time, you may need to install the Device Simulation Framework (DSF).

To install DSF:

1. Browse to the folder where the DEK is installed (usually C:\Windows7DEK)
2. Navigate to the Tools\MTP Device Simulator\Dsf subfolder
3. Open an elevated command window (i.e. "Run as Administrator”) and launch install.cmd to start the DSF MSI package install.

Once DSF is installed, you can launch the MTP Simulator from C:\WindowsDEK\Tools\MTP Device Simulator\MTPSimUI.exe. Select your desired transport, and click “Connect” to launch an instance of the MTP Simulator. The next section gives an overview of the User Interface.

User Interface

The following screenshot shows the MTP Simulator UI with navigation buttons and configuration options.

MTP Simulator Configuration	Location	Purpose
Connection	Left control tabs and menu options.	Connect, disconnect, or restart MTP Simulator by using the currently selected configuration. You can change the transport type on the Transport tab and change the test mode on the Device Mode tab.
Transport	Left control tabs and menu options.	Select the transport to be used. To simulate a software-only USB device, select the “SoftUSB” transport.
Device mode	Left control tabs and menu options.	Normal Mode should be used. Test Mode is reserved for internal Microsoft testing.
Output windows	Lower-right output window.	This window displays redirected output from stdout. Any output from a printf statement, such as trace—from either MTP Simulator or a plug-in—appears in this window. The output is also saved as mtpsimui.log automatically under the MTP Simulator root directory.

Table 1. MTP Simulator User Controls

Command-Line Options

In addition to the GUI, you can control MTP Simulator at startup by using command-line parameters. This can be useful when you need to perform automated testing. For details, see Appendix C from the MTP Device Simulator User Guide.

Customizing the MTP Simulator

You can control the capabilities that the MTP Simulator reports to Windows by using an XML file (see Appendix F in the MTP Device Simulator User Guide for details). Device capabilities are controlled by DeviceSummary.xml, and service capabilities are controlled by Services.xml.

The DeviceSummary.xml file enables you to customize the contents of the DeviceInfo, StorageInfo, DevicePropDesc, and ObjectPropDesc datasets.

The Services.xml file enables you to specify configurations that are related to device services, including service-supported formats, methods, and events.

Device Profiles

The MTP Simulator also supports loading different device profiles. A device profile contains a set of customized configuration files (i.e. DeviceSummary.xml and Services.xml) describing a sample device. The DEK comes bundled with sample profiles representing each device class (Camera, Cellular Phone, Media Player, etc). Details of how to load the device profiles are outlined in the MTP Device Simulator User Guide.

Device Profile	Description
Fabrikam_Camera	Simulates a sample camera.
Fabrikam_Phone	Simulates a cellular phone.
Fabrikam_PMP	Simulates a portable media player.
MtpSim-FullEnumSync	Simulates a device that supports the Full Enumeration synchronization model, for example for contacts, calendar, tasks, and notes synchronization.
MtpSim-FullEnumSyncSimpleParticipant	Simulates a device that supports the Full Enumeration synchronization model (like MtpSim-FullEnumSync), with additional support for the simple participant feature.

Table 2: Sample MTP Simulator Device Profiles

Each of these profiles has a corresponding Device Stage package. Each of these packages supports the same set of standard Device Stage tasks, with the exception of the Ringtone task which is not supported by the Fabrikam_Camera and Fabrikam_PMP profiles. For more information on authoring Device Stage metadata, refer to the Windows 7 Device Stage Development Guide in the Microsoft Device Experience Development Kit.

Testing Device Stage Packages

The MTP Simulator can also be used to test custom Device Stage packages. The MTP Device Inspector tool can be used to generate a device profile which can be loaded into the Simulator (see the MTP Device Simulator User Guide for details). Once a custom Device Stage metadata package has been authored, the package contains all the files necessary to display a Device Stage experience in Windows 7. The package may be tested by copying it to the PC’s device metadata store and connecting the test device, in this case rapid development can be done using the MTP Simulator. In order to load (unsigned) custom Device Stage metadata the system will need to be boot into test mode. For more details, refer to page 40 of the Windows 7 Device Stage Development Guide document that is included in the Microsoft Device Experience Development Kit for details on testing Device Stage metadata packages.

Want to Learn More?

The MTP Device Simulator User Guide in the Documentation for the Device Enabling Kit contains more information on the features described above.

If you have general questions about the MTP Simulator contact AskMTP at Microsoft dot com.

This posting is provided "AS IS" with no warranties and confers no rights.

This blog post covers the following topics:

• What is the Windows Logo Program for Hardware?
• Supported Portable Device Logo Programs
• Prepared Requirement Reports
• Windows Logo Kit
• Additional Information on the Windows Logo Program for Hardware
• Development Tools and Support

What is the Windows Logo Program for Hardware?

The Windows Logo Program is designed to address the current and future market needs of customers using the Windows platform. The Windows logo signifies the compatibility and reliability of systems and devices with the Windows operating system. It gives customers confidence that your product is thoroughly tested with Microsoft-provided tools and ensures a good user experience.

The Windows Logo Program helps partners to innovate and bring a premium experience to market, thereby improving their ability to increase market share. The program strives to continuously improve its processes, responsiveness, and partner satisfaction.

Supported Portable Device Logo Programs

There are currently 3 logo categories that are accepting submissions for Portable Devices, they are:

Digital Still Camera- This program supports logo for Windows 7 and Windows Vista

Portable Media Player- This program supports logo for Windows 7 and Windows Vista. The PlaysForSure program was retired at the end of August 2009.

Cellular Handset (Phone)- This program supports logo for Windows 7, Windows Vista, and Windows XP.The PlaysForSure program was retired at the end of August 2009.

With the release of the Windows Logo Kit (WLK) 1.5, which is due to release at the end of November 2009, we will see one additional category:

Other Portable Devices - This program supports logo for Windows 7.

This new category is being made available as an option for hardware manufacturers that support the core set of MTP Revision 1.0 operations, device properties, and object formats. Passing this logo program provides validation that the device has implemented the MTP protocol correctly, so that the device will work as expected with the MTP class driver in Windows 7.

The following table provides a breakdown of requirements for each of these 4 categories. The ‘R' in the table implies that the operation,property, or object format is required. If the field is blank the requirement is optional.

RequiredOperations

See Appendix D - Operations in the MTP Specification, Revision 1.0 for complete list of defined MTP Operations.

Required Device Properties

See Appendix C - Device Properties in the MTP Specification, Revision1.0 for complete list of defined Device Properties.

(1)Digital Cameras are required to support Battery Level after June 2010.

Required Object Formats

The following table represents the list of required object formats for a portable device. Each object format also has a list of object properties that must be supported per object type. See requirement PORTABLE-0064 for more details.

(2) Portable devices that are capable of playing audio and/or video must support at least one of these formats.  This table does not represent the complete list of supported formats; it represents the list of commonly used formats.

See Appendix A - Object Formats in the MTP Specification, Revision 1.0 for complete list of defined Device Properties. 

Prepared Requirement Reports

The Windows Logo Program for Hardware creates a list of requirements that the validation tests are based on. During the hardware design phase it is critical that manufacturers that are going to be involved with the logo process review the logo requirements that are applicable to a target OS,such as Windows 7. Although the majority of requirements that are outlined for Portable Devices are based on industry standards and specifications or white papers published by Microsoft, there are some requirements that may not be apparent until you attempt to run through the WLK and come across a failure that you do not expect. For example, we have portable device specific behavior requirements defined but there are also fundamental requirements that apply to all devices for Windows. There are also requirements that apply to all USB devices, one such requirement is support for USB serial numbers for all portable USB devices. Additional requirements can be reviewed by downloading the Prepared Requirements Reports which are organized by specific hardware technologies.

Windows Logo Kit

The Windows Logo Kit (WLK) is used to validate the requirements defined for the logo program. This kit can also be used for product development. We encourage its use during the product development cycle of hardware in order to ensure device compliance with both Windows and industry standards. The kit includes several tests designed to validate device implementation and behavior at multiple levels. There are tests for USB compliance, MTP compliance, and WPD platform compliance that also cover device services validation. 

Thecore tests provided for portable devices are:

• MTP Compliance Tests
• WPD Compliance Tests
• WMDM Compliance Tests
• WMDM Sync Test

For detailed description of these tests, please go to the WLK help documentation.

There is a significant amount of information available about the WLK, including user guides and video tutorials. For more information about the WLK see: https://www.microsoft.com/whdc/winlogo/WLK/default.mspx

The kit is free to download and use.

Additional Information on the Windows Logo Program for Hardware

There is a wealth of additional information that has been made available for this program. Here are some of the key helpful links that will help you navigate the logo program.

• https://www.microsoft.com/whdc/winlogo/default.mspx
• https://msdn.microsoft.com/en-us/library/cc300359.aspx
• https://www.microsoft.com/communities/newsgroups/list/en-us/default.aspx?dg=microsoft.public.development.device.drivers.dtm&cat=en_us_7CF920C0-483A-5AF9-37A8-BB5310F0ACF4&lang=en&cr=us

We strongly encourage anyone that is going to participate in the logo program to review the Windows Logo Program Webcasts as well. These are a series of videos that can be viewed on demand that covers logo planning, testing, development, and how to submit logo packages using the qualification page at https://winqual.microsoft.com.

Development Tools and Support

There are several development resources available for portable device manufacturers. Probably the best source for this information was put together and released as a WPD Team Blog back in September, refer to Windows7 Portable Device Development Kits for details. That blog post covered the following development resources:

• Windows 7 Portable Device Enabling Kit for MTP
• Windows Portable Devices SDK
• Windows Portable Devices Driver Kit
• Windows Media Device Manager SDK
• Microsoft Device Experience Development Kit
• Windows Logo Kit

If you have general questions about MTP or WPD development, contact AskMTP at microsoft dot com.

This posting is provided "AS IS" with no warranties and confers no rights.

The following sections describe each sample application, the modules found in that application, and the operating systems that it will run on.

WpdApiSample

Of the two sample applications, the WpdApiSample, is the most generalized. It demonstrates how a developer would use the WPD API to accomplish tasks common to most applications. For example, this application demonstrates how a developer would:

· Enumerate the devices connected to a computer.

· Establish a connection to a connected device.

· Enumerate device content.

· Retrieve the properties for a given object on a device.

· Set the properties for a given object on a device.

· Retrieve general device information (for example, a description of the operations that a device can perform).

· Operate on device content (for example, move a file from one folder on the device to another).

The WpdApiSample application includes the following files:

This application is supported on Windows XP, Windows Vista, and Windows 7.

Even if you have no WPD devices connected to your computer, you can familiarize yourself with the WPD API and this application by installing the WpdHelloWorldDriver sample from the Windows Driver Kit (WDK), which emulates a simple WPD device. For information about downloading the WDK, see https://www.microsoft.com/whdc/resources/downloads.mspx

WpdServiceApiSample

The WpdServiceApiSample sample demonstrates how a developer would use the WPD API to explore a Contacts Device Service on a device that’s attached to a computer. For example, this application demonstrates how a developer would:

· Enumerate the services on a devce.

· Open a service.

· Enumerate service content.

· Retrieve the events and methods supported by a service.

· Access the service object properties.

· Invoke service methods (both synchronously and asynchronously).

The WpdServiceApiSample application includes the following files:

Because Device Services is new for Windows 7, this application is only supported in the Windows 7 operating system.

Even if you have no WPD devices connected to your computer, you can familiarize yourself with the WPD API and this application by installing the WpdServiceSampleDriver that’s included as a sample in the Windows Driver Kit (WDK). This sample driver emulates a simple WPD device service.

Other Samples

In addition to the two samples that ship in the SDK, the WPD team created three other samples that demonstrate using WPD to display the current office temperature in the Windows Sidebar. One of these samples is written using unmanaged-code and C++; another is written using the COM interop and Visual Basic .Net; and, the third is written using the COM interop and Visual C# .Net.

All three of these samples rely on a simple temperature sensor device, device-firmware, and a sample WPD driver. You can download the circuit description, device-firmware, and sample driver from here: https://www.microsoft.com/whdc/device/media/WPD_drv.mspx

Once you build the device, download the firmware, and install the driver, you can begin exploring the WPD API samples. You’ll find a description of the unmanaged application at: https://blogs.msdn.com/wpdblog/archive/2007/12/19/creating-a-temperature-sensor-gadget-for-windows-sidebar-with-c.aspx.

You’ll find a description of the COM interop and Visual Basic .Net application at: https://wpdtempsensor.codeplex.com/.

And, you’ll find a description of the COM interop and the C# application at: https://blogs.msdn.com/wpdblog/archive/2007/11/26/creating-a-temperature-sensor-gadget-for-windows-sidebar.aspx.

This posting is provided "AS IS" with no warranties and confers no rights.

The Windows Portable Devices Driver Kit in the Windows Driver Kit (WDK) comes bundled with five WPD sample drivers. Two of these drivers, WpdHelloWorldDriver and WpdWudfSampleDriver, were available in previous versions of the WDK. The remaining three drivers, WpdBasicHardwareDriver, WpdServiceSampleDriver, and WpdMultiTransportDriver, are new additions in the Windows 7 WDK. Together, these samples illustrate how to build a WPD driver for the different scenarios that WPD enables, including interaction with basic hardware, media synchronization, device services, and multi-transport.

We had mentioned these samples in a previous post on the Windows 7 Portable Devices Development Kits. The purpose of this post is to spend some time covering each sample in greater detail. Hopefully, this will help driver developers navigate the various WPD samples, and figure out which sample(s) best fit their driver requirements.

The following sections will describe each driver, the WPD commands that each implements, and the operating systems that each supports. In addition, we will provide the links to instructions for building and installing.

WpdHelloWorldDriver

Of all the sample drivers, the WpdHelloWorldDriver is the most simple. This driver supports and emulates four objects in software: a device object, a storage object, a folder object, and a text file object. WpdHelloWorldDriver was designed to provide the most basic scaffolding or skeleton required for developing a WPD driver; similar to the canonical "Hello World" program used for introducing a framework or programming language. If you are new to WPD driver development and need a kick start, we recommend starting with this sample.

The WpdHelloWorldDriver sample supports 22 commands. These commands cover the basic functionality that enables a WPD device to be browsed in Windows Explorer as a read-only device. The commands fall into four categories: object enumeration, object properties, object resources, and device capabilities. Like all WPD drivers, when this driver is installed and a WPD application calls a method to enumerate objects, set a property, open a resource, and so on, the driver will invoke a corresponding command handler for one of these supported commands.

This driver is supported on Windows XP, Windows Vista (x86, amd64), and Windows 7 (x86, amd64).

For instructions on how to build and install this driver, see: https://msdn.microsoft.com/en-us/library/dd573842.aspx

WpdBasicHardwareDriver

The WpdBasicHardwareDriver sample is new for Windows 7 and builds upon the WpdHelloWorldDriver. This sample stands apart from the other WPD samples in that it accesses real device hardware instead of emulating a software-only device. We provided this sample to demonstrate how a basic WPD driver can be built to interact with simple devices.

For our demonstration device, we targetted a “hobbyist” microcontroller that reads data from a variety of sensors. The sensors include: a 2-axis accelerometer, a 3-axis accelerometer, a temperature/humidity sensor, a pressure sensor, a distance sensor, a passive infrared sensor, a compass, a vibration sensor, and a light sensor. These sensor devices are controlled by a Parallax BS2 microcontroller attached to the PC via an RS232 port. In addition to the driver source code, we also provided some sample firmware code that retrieves the sensor data and sends them over the serial port to the PC.

The WpdBasicHardwareDriver sample supports an even smaller set of commands than the WpdHelloWorldDriver. In the interests of only providing the code that is necessary to demontrate the concepts, we removed some commands for object resources because the WpdBasicHardwareDriver does not need to support reading of files from the device. The remaining commands fall under these three categories: object enumeration, object properties, and device capabilities. To see this driver in action, you can use WpdMon to view the events corresponding to each sensor reading.

This sample also showcases how WPP Software Tracing can be used for error checking macros. A while ago, we had a post that describes how you can migrate your existing WPD driver from OutputDebugString to WPP Tracing. The WpdBasicHardwareDriver is now bundled with the macros. 

This driver is supported on Windows XP, Windows Vista (x86, amd64), and Windows 7 (x86, amd64). If you plan to develop drivers that integrate sensors with Windows 7, we recommend using the Sensor API and Sensor Driver Model. If you need to develop drivers to integrate sensors with Windows Vista or Windows XP, WPD provides a viable solution. 

For instructions on how to build and install this driver, see: https://msdn.microsoft.com/en-us/library/dd573829.aspx

WpdWudfSampleDriver

The WpdWudfSampleDriver is a comprehensive driver sample that demonstrates using the WPD DDI for media transfer scenarios.  In addition to file browsing and transfer via Windows Explorer, this sample contains additional functionality that supports media synchronization with Windows Media Device Manager (WMDM) applications (e.g. Windows Media Player), and photo acquisition with Windows Image Acquisition (WIA) applications (e.g. Paint). All interactions with hardware are emulated in software (meaning that this driver talks to a "fake" device).

To enable the media transfer scenarios, the WpdWudfSampleDriver sample had to support a large set of commands, including the commands supported by the WpdHelloWorldDriver. These commands can be divided into eight categories: object enumeration, object management, object properties, bulk properties, object resources, capabilities, and storage.

In this version, we fixed a compatibility issue in the Vista WDK version of the sample driver code that prevents it from being properly enumerated in Windows Media Player.

This driver is supported on Windows XP, Windows Vista (x86, amd64), and Windows 7 (x86, amd64).

For instructions on how to build and install this driver, see: https://msdn.microsoft.com/en-us/library/dd573843.aspx

WpdMultiTransportDriver

The WpdMultiTransportDriver builds upon the WpdHelloWorldDriver and demonstrates how driver developers can take advantage of the Windows 7 support for Multiple Transports. For an overview on what multi transport is all about, check out our post two weeks ago about Multi-Transport support in Windows 7.

This driver emulates a transport driver and illustrates how to set the relevant multi-transport settings and generate the Functional Unique Identifier (FUID) during device arrival, in order to perform handshaking with the WPD Composite Driver. In addition, this sample supports multiple Windows Driver Framework I/O queues, where all the other WPD samples only support a single I/O queue. 

Other than the multi-transport support, the WpdMultiTransportDriver sample is virtually identical as the WpdHelloWorldDriver, and supports the same set of WPD commands. A quick way to zero-in on the code modifications needed to support Multi-Transport is to use your favorite diff program to compare the WpdHelloWorldDriver and WpdMultiTransportDriver source folders.

Because multi-transport support is a new feature in Windows 7, this sample driver is only supported on Windows 7 (x86, amd64).

For instructions on how to build and install this driver, see: https://msdn.microsoft.com/en-us/library/dd573843.aspx

The WpdServiceSampleDriver demonstrates how a driver can support Windows 7 Device Services.  We covered an introduction to Device Services in another recent post. This driver emulates a basic Contacts device service that uses the Full Enumeration Sync device service. To support Device Services, this driver implements device services-specific WPD command sets: WPD_CATEGORY_SERVICE_COMMON, WPD_CATEGORY_SERVICE_CAPABILITIES, and WPD_CATEGORY_SERVICE_METHODS. These commands would allow an application to determine the capabilities of a service and invoke methods supported by the service. This driver also uses the new functionality in the WPD Class Extension (IPortableDeviceClassExtension) to register and unregister the Contacts device service interface. Last but not the least, to support object and property management, this sample also supports commands for object enumeration, object properties, bulk properties, object resources, and device capabilities.

The WpdServiceSampleDriver does not emulate a Media Transfer Protocol (MTP) device. Like most of the other WPD samples, it simulates a software-only device that is not tied to a specific protocol or transport. If you are looking to build firmware for an MTP device that supports device services, you should start with the Device Enabling Kit.

Device Services is a new feature we introduced in Windows 7, therefore this sample is only supported on Windows 7 (x86, amd64).

For instructions on how to build and install this driver, see: https://msdn.microsoft.com/en-us/library/dd573846.aspx

This posting is provided "AS IS" with no warranties and confers no rights. 

This post provides a description for the following development kits:

•  Windows 7 Portable Device Enabling Kit for MTP
• Windows Portable Devices SDK
• Windows Portable Devices Driver Kit
• Windows Media Device Manager SDK
• Microsoft Device Experience Development Kit
• Windows Logo Kit

Windows 7 Portable Device Enabling Kit for MTP

This development kit is designed to assist portable device manufacturers in the development of Media Transfer Protocol (MTP) device firmware that is compatible with the various MTP device transports that Windows supports, and with Device Services. There are two packages provided for download:

Windows 7 Portable Device Enabling Kit for MTP - Tools
The tools kit includes design documentation and implementation guidelines, a Windows-based reference design, development tools, and the updated MTP Device Simulator.

Windows 7 Portable Device Enabling Kit for MTP - Reference Code
The reference code kit includes the core responder reference source code that is being made available under a separate Berkeley Software Distribution (BSD)–style license.

To download both packages of the Windows 7 Portable Device Enabling Kit for MTP, go to: https://www.microsoft.com/whdc/device/wpd/MTP-DEK_Win7.mspx

You are not required to license the reference code in order to use the tools and resources provided in the tools kit. This kit is free to download and use.

Windows Portable Devices SDK

The WPD SDK includes two sample applications for C++/COM developers. The first, WpdApiSample, is a command-line desktop application that demonstrates how you would: enumerate connected devices, explore those devices, query device-objects for properties and attributes, send and retrieve data, and so on. The second sample, WpdServicesApiSample, is a command-line desktop application that demonstrates how you would explore a Contacts service on a device that is attached to your computer.

The WPD SDK also includes an Automation Object Model that is supported in Windows 7. Developers can use the Automation model to write web applications that accomplish tasks similar to those accomplished with the API. We provided an introduction to WPD Automation in this recent post.

The WPD SDK is included in the Windows SDK which can be downloaded from https://www.microsoft.com/downloads/details.aspx?FamilyID=c17ba869-9671-4330-a63e-1fd44e0e2505&displaylang=en

The documentation for the WPD SDK (both the API and Automation Object Model) is found on MSDN at: https://msdn.microsoft.com/en-us/library/dd388998(VS.85).aspx

Windows Portable Devices Driver Kit

The WPD Driver Kit includes a Device Driver Interface (DDI) that is supported in Windows 7, Windows Vista, and Windows XP operating Systems. Developers will use this DDI to write drivers for devices that are not already supported by the MTP or Mass Storage class drivers that Microsoft distributes.

The WPD Driver Kit includes five sample device drivers which are described in the following table. In the next post, we covered each sample in more detail.

Sample Driver	Description
WpdHelloWorldDriver	This is the most basic WPD driver that emulates interaction with hardware. Supports four objects: device, storage, folder, and file. This provides the scaffolding or skeleton for developing a WPD driver.
WpdBasicHardwareDriver	Builds upon the WpdHelloWorldDriver and demonstrates interaction with simple hardware devices. Supports nine sensor devices: 2-axis accelerometer, 3-axis accelerometer, temperature/humidity sensor, pressure sensor, distance sensor, passive infrared sensor, compass, vibration sensor, and light sensor. These sensor devices are simple devices that are controlled by a Parallax BS2 microcontroller attached to the PC. If you plan to develop drivers that integrate sensors with Windows 7, we recommend using the Sensor API and Sensor Driver Model. If you need to develop drivers to integrate sensors with Windows Vista or Windows XP, WPD provides a viable solution.
WpdServiceSampleDriver	Demonstrates how a developer would extend the WpdHelloWorldDriver to support a simulated device with a Contacts device service.(Using this service, WPD applications can discover events, methods, and properties associated with the Contacts stored on the device. This sample emulates interaction with hardware.
WpdMultiTransportDriver	Demonstrates how developers can take advantage of the Windows 7 support for multiple transports. The sample emulates interaction with hardware and demonstrates support for the following transports: IP, Bluetooth, and USB. We covered an overview of Multi-transport support in Windows 7 here.
WpdWudfSampleDriver	A comprehensive sample driver that demonstrates what to enable in the WPD DDI for media transfer scenarios (such as music and photos). This sample supports media synchronization with Windows Media Player, and also emulates interaction with hardware.

The WPD Driver Kit is included in the Windows Driver Kit (WDK). For information about downloading the WDK, see: https://www.microsoft.com/whdc/devtools/wdk/WDKpkg.mspx

The documentation for the WPD Driver Kit is found on MSDN at: https://msdn.microsoft.com/en-us/library/dd419925.aspx

Windows Media Device Manager SDK

The Windows Media Device Manager (WMDM) SDK enables you to build desktop applications and components that can communicate with connected portable devices. WMDM enables your application or component to enumerate, explore, and exchange files with a device, query for metadata, and request play count information. Applications or components built on WMDM have a consistent API for communicating with a wide range of devices including Media Transfer Protocol (MTP), Mass Storage Class (MSC), RAPI, and other devices built on both the latest and previous versions of Windows Media technology.

The Windows Media Device Manager SDK is available at: https://msdn.microsoft.com/en-us/windows/bb190309.aspx.

Microsoft Device Experience Development Kit

The Microsoft Device Experience Development Kit provides detailed information and material that you would need to know in order to develop Device Stage™ experiences for Portable Devices. The development kit includes device development guides, planning worksheets, tutorials, and development samples that you can use when developing a Device Stage experience on Windows 7. For portable devices, Device Stage supports the industry-standard Media Transfer Protocol (MTP) 1.0 with device services that enable a new rich set of features in Windows 7.

The development kit along with other pertinent information to build a complete Windows Device Experience is available at: https://www.microsoft.com/whdc/device/DeviceExperience/default.mspx

The kit is free to download and use.

Windows Logo Kit

The primary use of the Windows Logo Kit (WLK) is for Windows Logo Program device certification. This kit can also be used for product development. We encourage its use during the product development cycle of hardware in order to ensure device compliance with both Windows and industry standards. The kit includes several tests designed to validate device implementation and behavior at multiple levels. There are tests for USB compliance, Media Transfer Protocol (MTP) compliance, and Windows Portable Devices (WPD) platform compliance that also cover device services validation. 

There is a significant amount of information available about the WLK, including user guides and video tutorials. For more information about the WLK see: https://www.microsoft.com/whdc/winlogo/WLK/default.mspx

The kit is free to download and use.

Other Resources

Windows Portable Devices node on Windows Hardware Developer Central

https://www.microsoft.com/whdc/device/wpd/default.mspx

Windows Portable Devices on Microsoft Developer Network

https://msdn.microsoft.com/en-us/library/dd388998(VS.85).aspx

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One way to address this would be to have the device provide its own identity that could be retrieved and examined by each application. This approach can work, but it requires that applications that rely on device identity be modified to use this new identity instead. It also wouldn’t account for future scenarios where multiple transports might be active at the same time.

There have been proprietary solutions, where a custom WPD driver was written to communicate with the device over any of its transports via a multi-transport-aware service. But to make this work, the hardware vendor was required to install and run a Windows service and a kernel mode bus enumerator that communicate with each other to load and unload drivers based on device presence.

The Composite Driver Solution

With Windows 7, there is now built-in support for devices with multiple transports. This support is currently limited to WPD devices, but the groundwork has been laid for other device classes in future OS releases. Now, when a multi-transport device is connected with a Windows 7 PC, it has a single identity. This is even true when multiple transports are simultaneously active, which with the added support for MTP over Bluetooth, will be a common occurrence, such as when a device already connected over Bluetooth is plugged into a USB port for charging.

The Windows 7 solution is a combination of the approaches mentioned above. The following diagram shows the general relationship between the components involved:

Each transport will continue to have a driver loaded that knows how to talk to the device over that transport. But this “transport” driver won’t be seen by applications. Instead, the transport driver will inform a system service (the Composite Bus Enumerator) that a transport is available. The Composite Bus Enumerator will keep track of the transports announced for any one device, and will cause a single Composite Driver to be loaded for that device. Only the Composite Driver will be seen by applications, and it will be the single point of contact with the device. This will be true whether the device has one transport active, or many, either sequentially, or simultaneously. When the last active transport is disconnected, the Composite Bus Enumerator will remove the Composite Driver.

Composite Driver

The Composite Driver has three primary functions. One, it chooses the best underlying transport when an application opens a handle to the device (typically via IPortableDevice::Open). Two, it acts as a pass-through for WPD requests and responses between the application and the transport drivers. And three, it acts as a proxy for registering and unregistering PnP interfaces on behalf of the underlying transport drivers. This latter functionality is how the transport drivers remain hidden from applications: since no PnP interfaces are registered by the transport driver, there is no (easy) way for an application to obtain a symbolic link directly to the transport. This latter functionality was also the most complex aspect of the implementation, where multiple transport drivers interacting with the Composite Driver to dynamically register and unregister interfaces must be made to look like a single underlying device.

How does the Composite Driver determine the “best” transport when multiple transports are simultaneously active? In Windows 7, it’s a simple comparison of reported theoretical maximum bandwidths reported by the transport driver to the Composite Driver: USB is faster than IP is faster than Bluetooth. While this is generally true, it is also theoretically possible for USB and IP to actually be slower than Bluetooth depending on conditions at the time. All are asynchronous protocols that rely on some form of bandwidth sharing.

Transport Drivers

What’s the difference between a transport driver and a regular driver? Not much. A transport driver has the added responsibility of communicating transport status with the Composite Bus Enumerator and the Composite Driver, but it is otherwise just a normal WPD driver. For instance, the Windows 7 MTP driver fulfills either duty depending on the capability of the underlying device. Much of the complexity is encapsulated in the WPD Class Extension (a helper object that manages the communication with the Composite Bus Enumerator and the Composite Driver).

Multi-Transport Capable Devices

What makes a device a multi-transport device? Simple: it just supplies a device property known as the Functional Unique ID (FUID). This is a 128-bit GUID (Globally Unique ID). For MTP devices, this property is defined by the new MTP Device Services Extension (see the MTP Device Services Extension Specification). This does not mean that the device must support services. It is perfectly okay for a device to indicate support for this extension, but only implement the parts that it needs (in this case, the “Functional ID” 0xD301 device property code).

The FUID must be unique across all devices of the same manufacturer, model and version. If two devices of the same model also had the same FUID, they would be treated as different transports of the same device. To avoid this, and to further simplify things for the device manufacturer, if the MTP driver finds an empty value for the FUID property on the device, it will automatically provision the device with a FUID generated at runtime. The only responsibility of the device manufacturer is to ensure that the FUID value is persisted across connections and available over all transports.

Writing your own Transport Driver

To help simplify the explanation so far, I’ve been describing how this works for an MTP device, where the system-provided MTP Class driver does most of the bookkeeping. However, this is supported for 3rd-party WPD drivers as well. Because most of the complexity is hidden from the driver by the WPD Class Extension, the driver just has to make a few simple adjustments to become multi-transport capable. This is covered in more detail in the documentation for the WPD Multi-Transport Sample driver, but the key changes are as follows:

1. In single-transport WPD drivers, the default I/O queue is sequential (a UMDF term for a queue that delivers one request at a time). The default I/O queue for a multi-transport driver must be parallel (a UMDF term for asynchronous delivery of I/O requests). WPD requests received in this queue shall be forwarded to the sequential WPD queue. All other requests are to be forwarded to a queue obtained from the WPD Class Extension.
2. On driver initialization (in the OnPrepareHardware callback), the driver must provision the device with a FUID (if necessary), and it must use the WPD Class Extension to inform the Composite Bus Enumerator of the Manufacturer, Model, Version and FUID values for the device.

Application Development Considerations

While applications are now largely isolated from the complexities of multi-transport devices, there are some things to be aware of, and things an application can do, to provide a better experience. When one transport goes away and another arrives for the same device, the Composite Driver may remain loaded during the transition, but it will not automatically “fail over” to the new transport. There are several reasons why this was not feasible, with limitations of the current MTP protocol being chief among them. The handle associated with the departed transport will no longer function (attempts to use it will result in an ERROR_DEVICE_REMOVED response). If other transports for the device are active, the Composite Driver will re-advertise the PnP interfaces available for the new best transport. But this does not lend itself to a seamless transition if the application treats it as a device departure followed by a device arrival.

The application can mitigate transport departures in a couple ways:

1. The application can close and reopen its handle at some scenario-specific interval (e.g., between object transfers when synchronizing with the device, or between user interactions with the device). This happens to be the way both Windows Media Player and the Windows Shell already behaved. This approach has the added benefit of guaranteeing that the fastest underlying transport will be used when multiple transports are simultaneously active.
2. The application can recognize that an ERROR_DEVICE_REMOVED failure might be transient and that it should try reopening the handle once before giving up on the device. Because the device has the same identity regardless of transport, the same symbolic link is used (and reused) across all transports.

This posting is provided "AS IS" with no warranties and confers no rights.

The Media Transfer Protocol (MTP) was originally created as an extension to the Picture Transfer Protocol but today it also supports media transfer, Device Services, command & control, and many other scenarios. MTP supports three transports: USB, IP, and Bluetooth.

One of most common drivers that WPD applications will interact with is the Media Transfer Protocol (MTP) driver.  MTP was introduced in Windows XP with an inbox user mode driver allowing for effortless device installation and connectivity.  MTP is standardized through the USB Implementer’s Forum (www.usb.org) and also features Windows-specific extensions.

We introduced a MTP driver for USB in Windows XP.  In Windows Vista, we added support for MTP over TCP/IP for devices that use WiFi and LAN connections.  In Windows 7, we continue the parade of MTP support with the introduction of Bluetooth.

MTP includes a protocol definition and several transport definitions.  As devices and PCs pick and choose which connectivity transports they support, device & application developers can be assured that the MTP protocol and WPD API will be consistent.   Three-transport support gives device manufacturers flexibility to choose wired or wireless, high or low power, faster or slower transfer speed, etc.  The MTP driver is also the first multi-transport driver in Windows, which means that a device manufacturer can feel free to implement all three and Windows will choose the best.  We’ll talk about that more in our next entry Multi-transport Devices in Windows 7.

Our first MTP transport driver is also the fastest and most powerful way to connect an MTP-enabled device.  Windows XP through Windows 7 support USB 1.1 or higher.  The binding of MTP to USB is described in the MTP specification itself (https://www.usb.org/developers/devclass_docs/MTP_1.0.zip)  and in the Still Imaging Capture Device Definition specification (https://www.usb.org/developers/devclass_docs/usb_still_img10.zip).  Windows XP uses the Microsoft OS Descriptor to identify MTP devices; Windows Vista and Windows 7 can identify MTP devices by either the OS Descriptor or the USB Still Image Class Code (Class 6, Subclass 1, Protocol 1).  Much of this is detailed in the Windows Portable Device Enabling Kit.

In Windows 7, we also enabled the USB Selective Suspend for the MTP driver, although this option is not enabled by default to preserve maximum ecosystem compatibility.

USB is great for fast file transfer, media synchronization, and charging the device while you’re using it.

In Windows Vista, we implemented MTP over TCP/IP to enable WiFi and networked devices to interact with WPD applications.  We used the PTP/IP binding (https://www.cipa.jp/ptp-ip/index_e.html), then used UPnP for pairing and discovery.  When devices report their presence on a network via UPnP after the initial pairing, Windows will automatically connect and make the device available to the user.

MTP/IP is ideal for devices with WiFi that can be connected and synchronized anywhere in the home.

In Windows 7, we introduced Bluetooth as the third transport for MTP. We implemented MTP over the L2CAP protocol for fast, efficient, and secure connections. The specification is available in the Windows Portable Device Enabling Kit. PC users can switch the connection on and off through the Devices & Printers folder, or devices themselves can initiate and terminate connections to the PC.

We also implemented an "auto connect" feature in which Windows attempts to connect to your device every few minutes to maintain a low power connection for automatic synchronization and status updates.  When you are holding the device near your PC, you’re connected; when you walk away, the connection breaks and waits silently to reconnect when you return and your device gets back into Bluetooth range.

Applications can use the IPortableDeviceConnect interface to issue connect/disconnect requests to an MTP/Bluetooth device.  When a connection request is made, the MTP/Bluetooth link is established, the WPD MTP driver stack will load, and the device becomes visible to WPD applications to connect to using the WPD API.

Windows requires Bluetooth 1.2 or higher with the Microsoft Bluetooth stack installed.  For maximum security, Windows also requires that the device is paired securely with a pin code.

MTP/BT is great for low power, low speed scenarios like synchronizing PIM data or a quick file transfer.

The MTP driver is present in Windows XP with Windows Media Player 10 or higher installed, Windows Vista, and Windows 7.

This posting is provided "AS IS" with no warranties and confers no rights.