AVI Decompressor Filter
A version of this page is also available for
4/8/2010
The Video/Image Compression Manager 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. All this happens automatically; your application is not responsible for these details.
The following table shows the filter properties.
| Filter property | Description |
|---|---|
Filter Interfaces |
|
Input Pin Media Types and Sub Types |
MEDIATYPE_Video, MEDIASUBTYPE_NULL, FORMAT_VideoInfo. The subtype must correspond to an old-style FOURCC. |
Input Pin Interfaces |
IMemInputPin Interface, IPin Interface, IQualityControl Interface |
Output Pin Media Types |
MEDIATYPE_Video, MEDIASUBTYPE_NULL, FORMAT_VideoInfo |
Output Pin Interfaces |
IMediaPosition Interface, IMediaSeeking Interface, IPin, IQualityControl |
Filter CLSID |
CLSID_AVIDec |
Property Page CLSID |
No property page. |
Executable |
Quartz.dll |
MERIT_NORMAL |
|
CLSID_LegacyAmFilterCategory |
Remarks
The media subtype on the pins is built from the FourCC code in the AVI file.