WM_CAP_SET_PREVIEWRATE message

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 Value

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

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 Capture

Video Capture Messages