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ICM_DECOMPRESS_BEGIN message

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The ICM_DECOMPRESS_BEGIN message notifies a video decompression driver to prepare to decompress data. You can send this message explicitly or by using the ICDecompressBegin macro.

ICM_DECOMPRESS_BEGIN 
wParam = (DWORD_PTR) (LPVOID) lpbiInput; 
lParam = (DWORD_PTR) (LPVOID) lpbiOutput;

Parameters

lpbiInput

Pointer to a BITMAPINFO structure containing the input format.

lpbiOutput

Pointer to a BITMAPINFO structure containing the output format.

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_DECOMPRESS messages efficiently.

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

The ICM_DECOMPRESS_BEGIN and ICM_DECOMPRESS_END messages do not nest. If your driver receives ICM_DECOMPRESS_BEGIN before decompression is stopped with ICM_DECOMPRESS_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
Vfw.h

See also

Video Compression Manager

Video Compression Messages