ICM_DECOMPRESSEX_BEGIN message
The ICM_DECOMPRESSEX_BEGIN message notifies a video compression driver to prepare to decompress data.
ICM_DECOMPRESSEX_BEGIN
wParam = (DWORD_PTR) (LPVOID) &icdex;
lParam = sizeof(ICDECOMPRESSEX);
Parameters
-
icdex
-
Pointer to a ICDECOMPRESSEX structure containing the input and output formats.
-
lParam
-
Size, in bytes, of ICDECOMPRESSEX.
Return Value
Returns ICERR_OK if the specified decompression is supported or ICERR_BADFORMAT otherwise.
Remarks
When the driver receives this message, it should allocate buffers and do any time-consuming operations so that it can process ICM_DECOMPRESSEX messages efficiently.
If you want the driver to decompress data directly to the screen, send the ICM_DRAW_BEGIN message.
The ICM_DECOMPRESSEX_BEGIN and ICM_DECOMPRESSEX_END messages do not nest. If your driver receives ICM_DECOMPRESSEX_BEGIN before decompression is stopped with ICM_DECOMPRESSEX_END, it should restart decompression with new parameters.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|