Features Added in the Windows Media 9.5 SDK
The Windows Media Format 9.5 SDK introduced new features to provide enhanced content security and flexibility. The following changes were made to the SDK since the 9 Series release.
Player applications that support DirectX Video Acceleration can now implement the IWMPlayerHook interface to perform application-specific processing during DirectX VA decoding. The reader calls the IWMPLayerHook::PreDecode callback method before passing compressed video samples to the video processor for decoding.
An x64-based version of the Windows Media Format SDK is available. This documentation applies to both the 32-bit versions and the x64-based version of the SDK. However, digital rights management (DRM) is not supported in the x64-based Windows Media Format SDK.
The Windows Media Video 9 Image v2 codec simplifies the sample geometry calculations for panning and zooming. The new codec also supports several complex transitions between images.
The Windows Media Format 9.5 SDK includes the following updated audio codecs:
- Windows Media Audio 9.1
- Windows Media Audio 9.1 Professional
- Windows Media Audio 9.1 Lossless
The Windows Media Format 9.5 SDK supports the new Windows Media DRM 10 for Network Devices secure transfer protocol. This protocol can be used to stream encrypted content over a local network to a playback device, such as a set-top video receiver.
Most of the procedures used to implement support for Windows Media DRM 10 for Network Devices must be performed by the application. However, you can use methods of the Windows Media Format SDK to provide the following functionality:
- Maintain a database of devices, including those that are enabled for Windows Media DRM 10 for Network Devices.
- Validate devices to ensure that they are "near" enough to the client on the network for secure streaming.
- Convert DRM-protected files to Windows Media DRM 10 for Network Devices streams.
- Write files using previously encrypted data.
New licenses created by using the Windows Media Rights Manager SDK use Output Protection Levels (OPLs) to specify rights and restrictions for playing and copying content. The Windows Media Format SDK provides support for reading the OPLs from a license.
The Windows Media Video 9 Advanced Profile codec builds on the high quality of the Windows Media Video 9 codec while adding support for interlaced encoding.
Content encoded with one of the Windows Media Audio Professional codecs can now be transferred or transmitted using the Sony/Philips Digital Interconnect Format (S/PDIF).
The Windows Media Audio 9.1 and Windows Media Audio 9.1 Professional codecs now each support several low-delay formats. These formats produce audio streams that can be started more quickly, reducing latency in stream-switching scenarios. Overall latency in live broadcasts is also improved by using low-delay formats.
You can now seek to an approximate time in an ASF file with the reader. This mode improves performance when performing an imprecise seek, such as when a user clicks the seek bar in Windows Media Player. Approximate seeking returns the media sample for the previous cleanpoint instead of reconstructing the sample for the precise time sought.
Windows Media DRM 10 supports rights for copying audio files to Red Book CD as part of a playlist. The Windows Media Format SDK provides methods for verifying whether the files in a playlist are allowed to be copied.
In the Windows Media Format 9 Series SDK, all metadata added to a file was assigned to a language list that was given the language identifier of the default language. This caused problems when content distributors in different locales added some metadata, because users in the distributor's locale only see the few attributes added for their language. The Windows Media Format 9.5 SDK solves this problem by not creating a language list until there are attributes from two languages present in the file. At that point, all of the metadata is associated with the locale of the second language, which then becomes the default. In this way, a content distributor can keep all of the original metadata for a file, such as title and author, intact while adding some attributes pertinent to their locale.
The installation package for the Windows Media Format 9.5 SDK installs the Windows Media Device Manager SDK. The documentation for the Windows Media Device Manager SDK can be found in the C:\WMSDK\WMFSDK95\WMDM\docs folder (your folder will be different if you do not install the Windows Media Format SDK in the default folder.)
This documentation includes information about using the Windows Media Audio and Video codecs outside of the Windows Media Format SDK. This documentation was originally released as part of a download from the Microsoft Developer Network. The sample applications that demonstrate using the codec DMOs directly are included in the Windows Media Format SDK installation along with headers.