The IAMVfwCaptureDialogs interface enables an application to display one of the three dialog boxes (Source, Format, or Display) provided by Microsoft® Video for Windows® capture drivers.
When to Implement
The Video for Windows VFW Video Capture filter implements this interface. It isn't expected that anything else will implement this interface.
When to Use
Any application that enables the user to change settings in a Video for Windows capture driver-supplied dialog box should use this interface.
Methods in Vtable Order
| IUnknown methods | Description |
| QueryInterface | Retrieves pointers to supported interfaces. |
| AddRef | Increments the reference count. |
| Release | Decrements the reference count. |
| IAMVfwCaptureDialogs methods | Description |
| HasDialog | Determines if the specified dialog box exists in the driver. |
| ShowDialog | Displays the specified dialog box. |
| SendDriverMessage | Sends a driver-specific message. |
Determines if the specified dialog box exists in the driver.
HRESULT HasDialog(
int iDialog );
Returns S_OK if the driver contains the dialog box or S_FALSE otherwise.
This method calls the Video for Windows videoDialog function to query for the existence of the appropriate dialog box.
Sends a driver-specific message.
HRESULT SendDriverMessage(
int iDialog,
int uMsg,
long dw1,
long dw2 );
Return value varies depending on the implementation within each driver.
You should never need to use this method. This method can send any private message to the capture driver. Behavior might be undetermined in response to arbitrary messages; use this method at your own risk.
This method calls the Video for Windows videoMessage function to send the driver message.
Displays the specified dialog box.
HRESULT ShowDialog(
int iDialog,
long hwnd );
Returns an HRESULT value that depends on the implementation of the interface.
You can't use this method when the driver is streaming or displaying another dialog box. While the driver displays the dialog box you can't stream (pause or run) the filter.
IAMVfwCaptureDialogs::ShowDialog calls the Video for Windows® videoDialog function to display the appropriate dialog box.
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