## IVPBaseNotify Interface

IVPBaseNotify enables you to control the properties of a filter that uses a video port. The IVPNotify interface derives from this interface. See also IVPBaseConfig and IVPConfig.

When to Implement

The Overlay Mixer filter implements this interface so you won't need to implement it in most cases. Implement this interface when you need to alter the default behavior.

When to Use

Use this interface in your application when you need to access video port properties.

Methods in Vtable Order

IUnknown methods | Description
QueryInterface | Retrieves pointers to supported interfaces.
AddRef | Increments the reference count.
Release | Decrements the reference count.

IVPBaseNotify methods | Description
RenegotiateVPParameters | Initializes the connection to the decoder.

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IVPBaseNotify::RenegotiateVPParameters

IVPBaseNotify Interface

Initializes the connection to the decoder.

HRESULT RenegotiateVPParameters(void) PURE;

##### Return Values

Returns an HRESULT value that depends on the implementation of the interface. HRESULT can include one of the following standard constants, or other values not listed.

Value | Meaning
E_FAIL | Failure.
E_POINTER | NULL pointer argument.
E_INVALIDARG | Invalid argument.
E_NOTIMPL | Method is not supported.
NOERROR | No error.

##### Remarks

The Overlay Mixer filter negotiates various parameters (by using the IVPBaseConfig interface) with the decoder or driver. Call this function if any of those parameters (such as the video format or size) change. Currently, the Overlay Mixer repeats the whole connection process. You can call this method even while the graph is playing.

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