ICM_DECOMPRESSEX_QUERY

wParam = (DWORD) (LPVOID) &icdex;
lParam = sizeof(ICDECOMPRESSEX);
 

Queries a video compression driver to determine if it supports a specific input format or if it can decompress a specific input format to a specific output format.

wParam
Address of a ICDECOMPRESSEX structure describing the input format.
lParam
Size, in bytes, of the ICDECOMPRESSEX structure.