Migrating from DirectShow to Media Foundation

Comparing Media Foundation with DirectShow

DirectX Video Acceleration (DXVA) 2.0 offers more efficient video acceleration, compared with DXVA 1.0, with more robust, streamlined video decoding, and extended use of hardware in video processing. With DXVA 2.0, Windows can handle some of the most demanding high-definition content with high quality and improved glitch resilience.

Color-space information is preserved throughout the video pipeline. Users can enjoy video content with full fidelity. Preserving color-space information also reduces unnecessary color-space conversions, which frees more cycles to process demanding HD content.

The enhanced video renderer (EVR) offers better timing support, enhanced video processing, and improved glitch resilience.

Migration Paths

The basic infrastructure is in place for Media Foundation to be expanded into a complete digital media platform. In the meantime, existing digital media APIs, including DirectShow, will continue to be used in applications written for Windows Vista. Your migration path depends on the type of application you are writing, whether you are writing a new application or maintaining an existing application, and whether you want to provide features that are specific to Windows Vista.

It is not expected that every digital media application will adopt Media Foundation immediately. The typical migration path will be to use existing SDKs, such as DirectShow and the Windows Media Format SDK, and incorporate Media Foundation as needed. However, the sooner you begin building with Media Foundation, the better positioned you will be to capitalize on the wave of next-generation premium content.

The following new features in DirectShow and Media Foundation will simplify the migration path to Media Foundation:

• Media Foundation uses a new model for video and audio transforms. Media Foundation Transforms (MFTs) are an evolution from DirectX Media Objects (DMOs), which were introduced in the DirectX 8.0 SDK. Compared with DMOs, the required behaviors of MFTs are more clearly specified, which makes it easier to write a correct implementation. In addition, MFTs can support hardware-accelerated video transforms.
• Media Foundation provides a new video renderer, called the Enhanced Video Renderer (EVR). The EVR uses the next version of DirectX Video Acceleration (DXVA 2.0) for more efficient video rendering, and it has a simpler API for creating custom video presenters. To make EVR adoption easier, DirectShow provides an EVR filter in Windows Vista. Internally, the DirectShow EVR and the Media Foundation EVR use the same mixer and presenter objects. If you write a custom presenter, it can be used with either Direct Show or Media Foundation. DirectShow applications that use the EVR filter for advanced video rendering will be well placed to convert to a Media Foundation implementation in the future.
• With DXVA 2.0, video acceleration is now available directly to user-mode components without needing to communicate with the DirectShow video renderer. Previously, DXVA was accessible only through the video renderer. Decoders can now take advantage of DXVA 2.0 to provide fast video decoding without any dependency on DirectShow. Applications can also use DXVA 2.0 to perform video processing operations, such as contrast and gamma adjustment.
  

Video Capture
For video capture, continue to use DirectShow.

Custom Plug-in Components

If you create custom filters for DirectShow, such as encoders or decoders, you should consider writing an MFT instead. Writing an MFT gives you the inherent advantages of the MFT model over filters or DMOs, lets you take advantage of DXVA 2.0, and positions your product to work within the Media Foundation pipeline as well as DirectShow. The choice of whether to write an MFT depends on several factors:

• If you have an existing DMO, converting it to an MFT is typically a straightforward process, because the basic design of the two APIs is similar.
• If you have already written a custom DirectShow filter, and the filter is meant to be used only within your own DirectShow application, there is probably no benefit to rewriting it as an MFT.
• Source and sink filters should generally not be written as MFTs.

Video Editing

Video editing is not the primary focus of this release of Media Foundation. If your application is written using DirectShow or DirectShow Editing Services, you should continue to use those. ㅡㅡ;

Conclusion

Media Foundation is the digital multimedia platform for Windows Vista and beyond. On Windows Vista, the primary focus of Media Foundation is premium content playback. Media Foundation does not yet completely replace DirectShow; for many applications, the best approach will be to use a blend of technologies. For premium content, Media Foundation today gives you the advantages of content protection and enhanced audio-video quality in the pipeline. Applications that incorporate Media Foundation are well positioned to take advantage of the next generation of digital media content.

The following table compares the features of Media Foundation with those of DirectShow.

Feature group	Feature	Media Foundation	DirectShow
Basic functionality	Audio and video rendering	Yes	Yes
	Event notification	Yes	Yes
	Device enumeration	No	Yes
	Component enumeration	Yes	Yes
	Synchronization to reference clock	Yes	Yes
	Seeking	Yes	Yes
	Improved stress resilience	Yes	No
Content protection	Component validation	Yes	No
	Content protection policy negotiation	Yes	No
	Interoperability between content protection technologies	Yes	No
	Protection against kernel-mode and user-mode threats	Yes	No
	Component revocation and renewal	Yes	No
	Video output protection management	Yes	Yes
Media tasks	Audio capture	No	Yes
	Video capture	No	Yes
	Video editing	No	Yes
	DVD playback and navigation	No	Yes
	MPEG-2 support	No	Yes
	ASF support	No	Yes
	TV technologies	No	Yes
	Stream buffer engine	No	Yes
	Encoder API	No	Yes
Video renderer	Substream mixing using per-pixel or planar alpha blending	Yes	Yes
	Customizable video composition	No	Yes
	Support for custom presenters	Yes	Yes
	Windowless rendering	Yes	Yes
	Multimonitor support	Yes	Yes
	DXVA	Yes	Yes
	DirectDraw exclusive mode	Yes	Yes
	Backward compatibility with existing applications	Yes	Yes
	Accurate frame stepping	Yes	Yes
	Alpha blending of image data	Yes	Yes
	Glitch resilience	Yes	No
	Enhanced video fidelity	Yes	No
	Enhanced content protection robustness	Yes	No
	Standalone use	Yes	No
	Standalone mixing component	Yes	No
Transforms (MFT or DMO)	Synchronous data processing	Yes	Yes
	Simple programming model	Yes	Yes
	Standalone use	Yes	Yes
	Multiple inputs and multiple outputs	Yes	Yes
	Dynamic number of streams	Yes	No
	Access to sample-level metadata	Yes	No
	In-place processing	Yes	Yes
	Dynamic format changes	Yes	No
	Quality adjustment	Yes	No
	Rate change	Yes	No

The following table compares the features of Media Foundation with those of the Windows Media Format SDK.

Feature group	Feature	Media Foundation	Format SDK
ASF file features	Audio and video streams	Yes	Yes
	Image streams	No	Yes
	Arbitrary streams (text, file, Web, custom data)	No	Yes
	Script commands	No	Yes
	Data unit extensions	Yes	Yes
	SMPTE time code support	No	Yes
	Mutual exclusion	Yes	Yes
	Stream prioritization	Yes	Yes
	Bandwidth sharing	No	Yes
	Indexes	Yes	Yes
	Markers	Yes	Yes
	Multiple bit rate stream	Yes	Yes
	Multiple language support	Yes	Yes
Codec features	CBR encoding	Yes	Yes
	VBR encoding	Yes	Yes
	Two-pass encoding	Yes	Yes
	High-resolution audio support	Yes	Yes
	Low delay audio	Yes	Yes
	S/PDIF audio output	Yes	Yes
	Video image	Yes	Yes
	Device conformance template	Yes	Yes
	Video complexity settings	Yes	Yes
	Frame interpolation	Yes	Yes
	DirectX Video Acceleration	Yes	Yes
File writing	Video resizing	Yes	Yes
	Color space conversion	Yes	Yes
	Audio resampling	Yes	Yes
	ASF file sink	Yes	Yes
	Network sinks	No	Yes
	Push sinks	No	Yes
	Watermarking support	No	Yes
	Input formats, input settings, and data unit extensions	Yes	Yes
	WMA smart recompression	No	Yes
	Multichannel audio	Yes	Yes
File reading	User-allocated sample support	No	Yes
	Synchronous reading	No	Yes
	Output format enumeration	Yes	Yes
	Multichannel audio	Yes	Yes
	MP3 support	Yes	Yes
	Network sources	Yes	Yes
Metadata	ID3 support	No	Yes
	Custom metadata	Yes	Yes
Digital rights management	Live DRM	No	Yes
	DRM Individualization	Yes	Yes
	Back up and restore DRM licenses	Yes	Yes
	View DRM attributes in the Metadata Editor	Yes	Yes
	Output protection levels	Yes	Yes
	License revocation	Yes	Yes
	Windows Media DRM for Network Devices	Yes	Yes
	Secure Audio Path	No	Yes
	Playlist burning	Yes	Yes
	Third-party transcription support	Yes	No
	Local license issuance	Yes	No
	Enhanced Windows Media DRM renewability	Yes	No

 

http://msdn.microsoft.com/en-us/library/dd757928(VS.85).aspx