The ICM_DECOMPRESS_BEGIN message is sent to a video compression driver for decompressing data. When the driver receives this message, it should allocate buffers and do any time-consuming operations so it can process ICM_DECOMPRESS messages efficiently.
Returns ICERR_OK if the specified decompression is supported. Otherwise, returns ICERR_BADFORMAT indicating that the input or output format is not supported.
To have the driver decompress data directly to the screen, an application sends the ICM_DRAW_BEGIN message.
ICM_DECOMPRESS_BEGIN and ICM_DECOMPRESS_END do not nest. If your driver receives an ICM_DECOMPRESS_BEGIN message before decompression is stopped with ICM_DECOMPRESS_END, it should restart decompression with new parameters.