ICM_GETBUFFERSWANTED

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The ICM_GETBUFFERSWANTED message queries a driver for the number of buffers to allocate. You can send this message explicitly or by using the ICGetBuffersWanted macro.

ICM_GETBUFFERSWANTED 
wParam = (DWORD) (LPVOID) lpdwBuffers; 
lParam = 0;

Parameters

lpdwBuffers

Address to contain the number of samples the driver needs to efficiently render the data.

Return Values

Returns ICERR_OK if successful or ICERR_UNSUPPORTED otherwise.

Remarks

This message is used by drivers that use hardware to render data and want to ensure a minimal time lag caused by waiting for buffers to arrive. For example, if a driver controls a video decompression board that can hold 10 frames of video, it could return 10 for this message. This instructs applications to try to stay 10 frames ahead of the frame it currently needs.

Requirements

**  Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
**  Windows 95/98/Me:** Included in Windows 95 and later.
**  Header:** Declared in Vfw.h.

See Also

Video Compression Manager, Video Compression Messages, ICGetBuffersWanted