ICM_GETBUFFERSWANTED message

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_PTR) (LPVOID) lpdwBuffers; 
lParam = 0; 


Parameters

lpdwBuffers

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

Return Value

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

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

 

 

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