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WM_CAP_SET_PREVIEWRATE

The WM_CAP_SET_PREVIEWRATE message sets the frame display rate in preview mode. You can send this message explicitly or by using the capPreviewRate macro.

WM_CAP_SET_PREVIEWRATE 
wParam = (WPARAM) (wMS); 
lParam = 0L; 

Parameters

wMS

Rate, in milliseconds, at which new frames are captured and displayed.

Return Values

Returns TRUE if successful or FALSE if the capture window is not connected to a capture driver.

Remarks

The preview mode uses substantial CPU resources. Applications can disable preview or lower the preview rate when another application has the focus. During streaming video capture, the previewing task is lower priority than writing frames to disk, and preview frames are displayed only if no other buffers are available for writing.

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 Capture, Video Capture Messages, capPreviewRate