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. Possible values are:
• 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 .NET 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.
The default value is VARIANT_TRUE.
IUnknown ReceiveProcObj [write-only] Sets the callback object pointer.
If not NULL, the ReceiveProc method of this interface will be called with every video 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).

Methods

HRESULT SetFOURCCEnabled(long lFOURCC, VARIANT_BOOL bAccept)

Description

Enables or disables accepting the media type of the corresponding FOURCC code as the input media type for the filter.

Parameters

lFOURCC

FOURCC code value of the media format.

bAccept

A Boolean value that indicates whether to accept the media type of the supplied FOURCC code. TRUE to accept; otherwise, false.

Comments

Note: Call the method before rebuilding the graph in order for the graph to reflect whether to accept the media type of the supplied FOURCC code.

Setting the value of lFOURCC to 0 means that the method will target all the RGB formats.

Returns

Return Description
S_OK Successful.
S_FALSE Otherwise.

HRESULT GetFOURCCEnabled(long lFOURCC, VARIANT_BOOL* pbAccept)

Description

Retrieves the state of a FOURCC code which indicates whether a media type is accepted as the input type for the filter.

Parameters

lFOURCC

FOURCC code value of the media format.

pbAccept

Pointer to a variable that will receive the state of the supplied FOURCC. TRUE indicates that the media type of the corresponding FOURCC is accepted as the input media type for the filter. FALSE indicates that the media type of the corresponding FOURCC is disabled and will not be accepted.

Comments

Setting the value of lFOURCC to 0 means that the method will target all the RGB formats.

Returns

Return Description
S_OK Successful.
S_FALSE Otherwise.

HRESULT GetFOURCCSelected(long* plFOURCC)

Description

Enables or disables accepting the media type of the corresponding FOURCC code as the input media type for the filter.

Parameters

plFOURCC

Pointer to a variable that will receive the FOURCC code of the currently selected media type on the filter's input pin.

Comments

Note: Call the method before rebuilding the graph in order for the graph to reflect whether to accept the media type of the supplied FOURCC code.

Returns

Return Description
S_OK Successful.
S_FALSE Otherwise.
Help Version 22.0.2022.4.7
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LEADTOOLS Filters C API Help

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© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.