WM ASF Writer Filter (Compact 2013)


The WM ASF Writer is a wrapper filter for a file writer object for Windows Media formats. The filter accepts a variable number of input streams and creates an Advanced Systems Format (ASF) file. The filter handles all compression and multiplexing (although the compression mechanism can be bypassed). You can use the WM ASF Writer in several different scenarios including digital video (DV) capture, audio recompression, and conversion of Audio-Video Interleaved (AVI) files. This filter provides the only way to create Microsoft® Windows Media™ Audio and Windows Media Video files in Microsoft DirectShow.

The following table shows the filter properties.

Filter Property


Filter Interfaces

IAMFilterMiscFlags, IBaseFilter, IFileSinkFilter2, IWMHeaderInfo3

Input Pin Media Types

Depends on the ASF profile. Typically uncompressed audio and video types, although the filter will accept compressed types if they match the ASF profile.

Input Pin Interfaces

IPin, IMemInputPin, IQualityControl, IAMStreamControl

Output Pin Media Types

Not applicable.

Output Pin Interfaces

Not applicable.

Filter CLSID






The only file-writing mode supported by this filter is AM_FILE_OVERWRITE. The mode is set with the IFileSinkFilter2::SetMode method.