ILMVCallback Interface

This is the interface for the LEAD Video Callback Filter.

Properties:

 

Type

Name

Description

VARIANT

InputPalette

[read-only] Use this property to read the input palette. This is valid only for videos that have an input palette (usually 8-bit).

The variant is returned as an array of bytes (VT_ARRAY | VT_UI1).

VARIANT

OutputPalette

Use this property to view and change the output palette. Keep in mind that when you change the output palette, the output pin will attempt to reconnect. It is recommended you rebuild the graph after you change the output palette to avoid broken graphs.

The variant should be an array of bytes (VT_ARRAY | VT_UI1).

double

CurrentPosition

[read-only] Use this property to get the position (in seconds) of the current sample passed to the callback. It is recommended you call this property to get the current position from inside ILMVUserCallback::ReceiveProc rather than trying to get the current position from the graph or LTMM object.

long

CurrentFramePosition

[read-only] Use this property to get the frame number of the current sample passed to the callback. It is recommended you call this property to get the current position from inside ILMVUserCallback::ReceiveProc rather than trying to get the current position from the graph or LTMM object.

VARIANT_BOOL

CallInSameThread

Enables or disables the calling of the CallbackProc notifications in the same thread that set the ReceiveProcObj property. The default value is VARIANT_TRUE.

 Possible values are:

 

 

Value

Meaning

 

 

VARIANT_TRUE

Call the notifications in the same thread that set the callback. This reduces the performance and requires the application to process messages, otherwise the callback will not get called. It is the default and is required for platforms that have problem with multithreading. VB 6.0 and dotnet applications should use this mode.

 

 

VARIANT_FALSE

Call the notifications in any thread of the process. Use this setting for best performance in platforms that can handle this. This is the recommended mode for C++ applications.

 

 

Interface Methods:

HRESULT put_ReceiveProcObj(IUnknown *pCallback)

Parameters

pCallback

a valid pointer to a user callback interface interface.

Description

(Write-only) Sets the callback object pointer.

If not NULL, the ReceiveProc method of this interface will be called with every audio buffer.

Set to NULL (or to "Nothing" in VB) if you do not wish to receive notifications anymore. (For example, before you delete (release) the callback object interface).

Return

S_OK if successful, S_FALSE otherwis.