When compressing data, your application can use the ICCompressorChoose function to create a dialog box in which the user can select the compressor. You can specify flags for this function to allow the user to specify the key-frame frequency and the movie-data rate, or to display a preview window.
The compressor selected by the user is automatically opened and its handle is returned in the hic member of the COMPVARS structure specified in ICCompressorChoose.
If you use ICCompressorChoose, use the ICCompressorFree function to close the compressor and free any resources associated with the COMPVARS structure.