ICM_DECOMPRESS_BEGIN

See also ICM_COMPRESS_BEGIN, ICM_DECOMPRESS, ICM_DECOMPRESS_END, ICM_DRAW_BEGIN

wParam = (DWORD) (LPVOID) lpbiInput;
lParam = (DWORD) (LPVOID) lpbiOutput;

Notifies a video decompression driver to prepare to decompress data.

• Returns ICERR_OK if the specified decompression is supported or ICERR_BADFORMAT otherwise.

wParam

Address of a BITMAPINFO structure describing the input format.

lParam

Address of a BITMAPINFO structure describing the output format.

When the driver receives this message, it should allocate buffers and do any time-consuming operations so that it can process ICM_DECOMPRESS messages efficiently.

If you want the driver to decompress data directly to the screen, send 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.