capPreviewRate macro (vfw.h)

Article
02/22/2024

The capPreviewRate macro sets the frame display rate in preview mode. You can use this macro or explicitly call the WM_CAP_SET_PREVIEWRATE message.

Syntax

void capPreviewRate(
   hwnd,
   wMS
);

Parameters

hwnd

Handle to a capture window.

wMS

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

Return value

None

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]
Target Platform	Windows
Header	vfw.h