Using Installable Compressors for Nonvideo Data

Installable compressors are not necessarily limited to video data. By using a different value than ‘vidc’ in the fccType member, you can specify that your installable driver expects to handle a type of data that is not video. Four-character codes for nonvideo data should also be registered.

While VidEdit does not support data that is not audio or video, MCIAVI does provide limited support for other data types, using installable renderers. If you create a stream with a four-character code type that does not represent audio or video, its type and handler information are used to search for a driver capable of handling the data. The search follows the same procedure used for installable compressor drivers.

Writing a driver to render nonvideo data is very similar to rendering video, with the following differences:

• The format used is not a BITMAPINFO structure. The format is defined by the class of decompressor.

• The ICM_DECOMPRESS messages are not used. All data is rendered using the ICM_DRAW messages because there is no defined decompressed form for arbitrary data.