The IAMVfwCompressDialogs interface enables an application to display a Video for Windows codec (compressor/decompressor) Configure or About dialog box and to set and retrieve compressor status.
When to Implement
Microsoft's video compression manager (VCM) compressor filter (AVI Compressor) implements this interface. Other filters should not need to implement it.
When to Use
An application should use this interface when it must enable the user to change compression settings in an VCM compressor's Configure dialog box or to view the compressor's About dialog box. Applications also use this interface to set and retrieve compressor status.
Methods in Vtable Order
| IUnknown methods | Description |
| QueryInterface | Retrieves pointers to supported interfaces. |
| AddRef | Increments the reference count. |
| Release | Decrements the reference count. |
| IAMVfwCompressDialogs methods | Description |
| ShowDialog | Displays the specified dialog box. |
| GetState | Retrieves the current configuration settings for the VCM codec currently being used. |
| SetState | Sets configuration for the ICM codec. |
| SendDriverMessage | Sends a driver-specific message. |
Retrieves the current configuration settings for the VCM codec currently being used.
HRESULT GetState(
LPVOID pState,
int *pcbState
Return value varies depending on the implementation within each driver.
This method calls the COM ICGetState macro.
Sends a driver-specific message.
HRESULT SendDriverMessage(
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 video compressor (codec). Behavior might be undetermined in response to arbitrary messages; use this method at your own risk.
This method calls the Video for Windows video compression manager (VCM) ICSendMessage function to send the message.
Sets configuration for the VCM codec.
HRESULT SetState(
LPVOID pState,
int cbState );
Return value varies depending on the implementation within each driver.
This method calls the COM ICSetState macro, which notifies a video compression driver to set the state of the compressor.
Displays the specified dialog box.
HRESULT ShowDialog(
int iDialog,
long hwnd );
Returns an HRESULT value that depends on the implementation of the interface.
This method returns an error 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.
IAMVfwCompressDialogs::ShowDialog calls the Video for Windows video compression manager (VCM) functions ICConfigure and ICAbout to display the appropriate dialog box.
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