Stream Buffer Source Filter

This topic applies only to Windows XP Service Pack 1 or later.

The Stream Buffer Source filter is the source filter for the Stream Buffer Engine. It reads content that the Stream Buffer Sink filter or Stream Buffer Sink2 filter has stored.

Filter Interfaces
Input Pin Media Types Not applicable
Input Pin Interfaces Not applicable
Output Pin Media Types All audio, video, and data types accepted
Output Pin Interfaces
[IMediaSeeking]( (see Remarks)
Filter CLSID CLSID_StreamBufferSource
Property Page CLSID Not applicable
Executable Sbe.dll
Category CLSID_LegacyAmFilterCategory


The Stream Buffer Source filter supports the IMediaSeeking interface for completed recordings only. For live content, use the IStreamBufferMediaSeeking interface, which has the same methods but slightly different behavior for each method. This reflects the fact that live content continuously grows on one end, as the show is being recorded, and shrinks on the other end, as backing files are deleted. See the description of the IStreamBufferMediaSeeking interface for details.

You can use the IStreamBufferMediaSeeking interface with completed recordings, but do not mix IStreamBufferMediaSeeking calls and IMediaSeeking calls. After the first call to an IStreamBufferMediaSeeking method, the filter will fail any subsequent calls to IMediaSeeking methods and will also fail any subsequent QueryInterface calls for the IMediaSeeking interface.

To use the IStreamBufferMediaSeeking methods, an application should query the filter directly. To use the IMediaSeeking methods, the application should query the Filter Graph Manager. The Filter Graph Manager routes the seek commands to the filter, as described in Seeking.

Beginning with Windows Media Center TV Pack 2008 and Windows 7, the Stream Buffer Source filter supports the .WTV file format. H.264 is added as the default supported media type. Several new interfaces are also added to the filter:

  • The ISBE2GlobalEvent and ISBE2SpanningEvent interfaces offer the ability to obtain event data from global spanning events and in-band spanning events, respectively. A global spanning event sends state information that applies to all streams in the pipeline. An in-band spanning event is an in-band event that can be recorded as part of the state information in a stream. For more information how to obtain data from global spanning events, see Receiving Spanning Events in the Stream Buffer Engine.
  • The ISBE2Crossbar interface provides the ability to define profiles of all media types (corresponding to output pins) for a Stream Buffer Source filter.
  • The ISBE2StreamMap interface provides the ability to enumerate streams that are available for mapping to a Stream Buffer Source filter's output pins, and specify custom mappings between streams and output pins.

For more information on crossbars, profiles, and stream mappings, see Stream Buffer Source Filter Enhancements in Windows 7.

Receiving Spanning Events in the Stream Buffer Engine

Stream Buffer Engine Filters

Using the Stream Buffer Engine