Microsoft DirectX 8.0

AVI Decompressor Filter

The AVI Decompressor is a wrapper filter for installable decompressors that support the Video Compression Manager (VCM) interface. The VCM interface is not a part of the DirectShow architecture, so a "wrapper filter" is required to enable these compressors to function in the context of a filter graph.

When the Filter Graph Manager is building a graph to render an AVI file, it checks the FOURCC in the file's AVI header to determine whether the video stream is compressed. If it is, the Filter Graph Manager adds the AVI Decompressor, which then searches the registry for an installed decompressor that can handle the file. (But if the AVI file was compressed with the Intel® Indeo® compression scheme, then the native Indeo DirectShow filter will be pulled into the graph instead of the AVI Decompressor.) All this happens automatically; your application is not responsible for these details.

On its upstream pin the AVI Decompressor typically connects to the AVI Splitter. On its output pin it typically connects to the Video Renderer.
Filter Interfaces IBaseFilter
Input Pin Media Types MEDIATYPE_Video, MEDIASUBTYPE_NULL, FORMAT_VideoInfo

The subtype must correspond to an old-style FOURCC. (For more information, see FOURCCMap Class.)
Input Pin Interfaces IMemInputPin, IPin, IQualityControl
Output Pin Media Types MEDIATYPE_Video, MEDIASUBTYPE_NULL, FORMAT_VideoInfo
Output Pin Interfaces IMediaPosition, IMediaSeeking, IPin, IQualityControl
Filter CLSID CLSID_AVIDec
Property Page CLSID No property page.
Executable quartz.dll
Merit MERIT_NORMAL
Category CLSID_LegacyAmFilterCategory

Remarks

The media subtype on the pins is built from the FourCC code in the AVI file.