CAPSTATUS structure (vfw.h)

The CAPSTATUS structure defines the current state of the capture window.

Syntax

typedef struct tagCapStatus {
  UINT     uiImageWidth;
  UINT     uiImageHeight;
  BOOL     fLiveWindow;
  BOOL     fOverlayWindow;
  BOOL     fScale;
  POINT    ptScroll;
  BOOL     fUsingDefaultPalette;
  BOOL     fAudioHardware;
  BOOL     fCapFileExists;
  DWORD    dwCurrentVideoFrame;
  DWORD    dwCurrentVideoFramesDropped;
  DWORD    dwCurrentWaveSamples;
  DWORD    dwCurrentTimeElapsedMS;
  HPALETTE hPalCurrent;
  BOOL     fCapturingNow;
  DWORD    dwReturn;
  UINT     wNumVideoAllocated;
  UINT     wNumAudioAllocated;
} CAPSTATUS, *PCAPSTATUS, *LPCAPSTATUS;

Members

uiImageWidth

Image width, in pixels.

uiImageHeight

Image height, in pixels

fLiveWindow

Live window flag. The value of this member is TRUE if the window is displaying video using the preview method.

fOverlayWindow

Overlay window flag. The value of this member is TRUE if the window is displaying video using hardware overlay.

fScale

Input scaling flag. The value of this member is TRUE if the window is scaling the input video to the client area when displaying video using preview. This parameter has no effect when displaying video using overlay.

ptScroll

The x- and y-offset of the pixel displayed in the upper left corner of the client area of the window.

fUsingDefaultPalette

Default palette flag. The value of this member is TRUE if the capture driver is using its default palette.

fAudioHardware

Audio hardware flag. The value of this member is TRUE if the system has waveform-audio hardware installed.

fCapFileExists

Capture file flag. The value of this member is TRUE if a valid capture file has been generated.

dwCurrentVideoFrame

Number of frames processed during the current (or most recent) streaming capture. This count includes dropped frames.

dwCurrentVideoFramesDropped

Number of frames dropped during the current (or most recent) streaming capture. Dropped frames occur when the capture rate exceeds the rate at which frames can be saved to file. In this case, the capture driver has no buffers available for storing data. Dropping frames does not affect synchronization because the previous frame is displayed in place of the dropped frame.

dwCurrentWaveSamples

Number of waveform-audio samples processed during the current (or most recent) streaming capture.

dwCurrentTimeElapsedMS

Time, in milliseconds, since the start of the current (or most recent) streaming capture.

hPalCurrent

Handle to current palette.

fCapturingNow

Capturing flag. The value of this member is TRUE when capturing is in progress.

dwReturn

Error return values. Use this member if your application does not support an error callback function.

wNumVideoAllocated

Number of video buffers allocated. This value might be less than the number specified in the wNumVideoRequested member of the CAPTUREPARMS structure.

wNumAudioAllocated

Number of audio buffers allocated. This value might be less than the number specified in the wNumAudioRequested member of the CAPTUREPARMS structure.

Remarks

Because the state of a capture window changes in response to various messages, an application should update the information in this structure whenever it needs to enable menu items, determine the actual state of the capture window, or call the video format dialog box. If the application yields during streaming capture, this structure returns the progress of the capture in the dwCurrentVideoFrame, dwCurrentVideoFramesDropped, dwCurrentWaveSamples, and dwCurrentTimeElapsedMS members. Use the WM_CAP_GET_STATUS message or capGetStatus macro to update the contents of this structure.

Requirements

See also

CAPTUREPARMS

Video Capture

Video Capture Structures

WM_CAP_GET_STATUS