Application Basics

[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

There is some extra processing that you must perform for any application that uses the Windows Media DRM Client Extended APIs. This topic describes the requirements for a simple application.

First, you must initialize the Windows Media DRM Client Extended APIs by calling the WMDRMStartup function. The objects of the SDK are COM objects, but you do not need to call CoIntialize, because the WMDRMStatup function initializes COM for you.

All of the objects of the Windows Media DRM Client Extended APIs are created using helper functions and methods. You never need to call CoCreateInstance to create an object. The first interface to instantiate for any application that uses the SDK is IWMDRMProvider, which you can use to instantiate all of the other base interfaces. To get an instance of IWMDRMProvider, you must call either WMDRMCreateProvider or WMDRMCreateProtectedProvider. The difference between these functions is that WMDRMCreateProvider creates an object that can in turn create only objects that do not support methods that require the stub library.

After you have an instance of IWMDRMProvider, you can create the other objects that you need by calling IWMDRMProvider::CreateObject.

When you are ready to exit your application, you must release the DRM subsystem resources by calling the WMDRMShutdown function. This function also shuts down COM for you.

The following code example demonstrates how to initialize and conclude an application that uses the Windows Media DRM Client Extended APIs.

#include <wmdrmsdk.h>
// TODO: Include other headers here as needed.

// This example demonstrates the code required in a single, simple
// main function. You will most likely break this code up into appropriate
// functions.
void main(void)
{
    HRESULT hr = S_OK;

    IWMDRMProvider*     pProvider     = NULL;
    // For the sake of example, this code will instantiate the
    //  IWMDRMLicenseQuery interface. The process is the same for the
    //  other base interfaces.
    IWMDRMLicenseQuery* pLicenseQuery = NULL;

    // Initialize the DRM subsystem.
    hr = WMDRMStartup();

    // Create a provider object, that can be used to create the other
    //  objects.
    if (SUCCEEDED(hr))
    {
        hr = WMDRMCreateProvider(&pProvider);
    }

    if(SUCCEEDED(hr))
    {
        hr = pProvider->CreateObject(
            IID_IWMDRMLicenseQuery, 
            (void**)&pLicenseQuery);
    }

    // TODO: Use the methods of IWMDRMLicenseQuery as required.

    // Cleanup and shutdown.
    SAFE_RELEASE(pLicenseQuery);
    SAFE_RELEASE(pProvider);

    hr = WMDRMShutdown();
}

Related topics

Getting Started