ILMMCommon Interface

This interface is exposed by the majority of LEAD filters. The interface provides basic functionality and information common to all filters that expose it.

This interface can be obtained using a direct QueryInterface call on the filter object.

A Note About BSTR Properties:

When "getting" a BSTR property, the memory containing the string is allocated with SysAllocString. When this string is no longer needed, free this memory by calling SysFreeString if you are working in an environment such as C or C++ that does not automatically delete the memory. VB automatically deletes the memory, so VB programmers do not need to free the memory themselves.

Interface Properties:

Type	Name	Parameter Description	Description
BSTR	FilterName		Contains the friendly name of the filter. A note about BSTR properties.
long	FilterState		Indicates the current filter state. Possible values are:
			Value	Description
			0	The filter is stopped.
			1	The filter is paused.
			2	The filter is running.
long	InputPinsCount		Contains the number of input pins on the filter.
long	OutputPinsCount		Contains the number of output pins on the filter.
BSTR	InputPinName (long nPinIndex)	The zero based index of the input pin to retrieve its name.	Contains the name of the input pin at the specified index. A note about BSTR properties.
BSTR	OutputPinName (long nPinIndex)	The zero based index of the output pin to retrieve its name.	Contains the name of the output pin at the specified index. A note about BSTR properties.
BOOL	IsLEADInputPinConnected (long nPinIndex)	The zero based index of the input pin to check its connection state.	Indicates whether the input pin at the specified index is connected to another pin.
BOOL	IsLEADOutputPinConnected (long nPinIndex)	The zero based index of the output pin to check its connection state.	Indicates whether the output pin at the specified index is connected to another pin.
long	InputPinStreamType (long nPinIndex)	The zero based index of the input pin to retrieve its stream type.	Contains the stream type of the input pin at the specified index. Possible values are:
			Value	Meaning
			AudioStream	[0] The stream type currently used is audio.
			VideoStream	[1] The stream type currently used is video.
			TextStream	[2] The stream type currently used is text.
long	OutputPinStreamType (long nPinIndex)	The zero based index of the output pin to retrieve its stream type.	Indicates the stream type of the output pin at the specified index. Possible values are:
			Value	Meaning
			AudioStream	[0] The stream type currently used is audio.
			VideoStream	[1] The stream type currently used is video.
			TextStream	[2] The stream type currently used is text.
long	InWidth (long nPinIndex)	The zero based index of the input pin to retrieve its connected video width.	Indicates the video width for the input pin at the specified index. (Applicable for video streams only).
long	InHeight (long nPinIndex)	The zero based index of the input pin to retrieve its connected video height.	Indicates the video height for the input pin at the specified index. (Applicable for video streams only).
long	OutWidth (long nPinIndex)	The zero based index of the output pin to retrieve its connected video width.	Indicates the video width for the output pin at the specified index. (Applicable for video streams only).
long	OutHeight (long nPinIndex)	The zero based index of the output pin to retrieve its connected video height.	Indicates the video height for the output pin at the specified index. (Applicable for video streams only).
long	InBits (long nPinIndex)	The zero based index of the input pin to retrieve its connected video bits per pixel.	Indicates the bits per pixel value of the video stream The portion of the file holding the video data. The video data might be compressed to save disk space. The data has to be decompressed using a video decompressor Also known as a decoder, this is a module or algorithm to decompress data. before you can play (see) it. for the input pin at the specified index. (Applicable for video streams only).
long	OutBits (long nPinIndex)	The zero based index of the output pin to retrieve its connected video bits per pixel.	Indicates the bits per pixel value of the video stream for the output pin at the specified index. (Applicable for video streams only).
long	InChannels (long nPinIndex)	The zero based index of the input pin to retrieve the number of channels for the connected audio stream.	Indicates the number of channels for the input pin at the specified index (Applicable for audio streams only).
long	OutChannels (long nPinIndex)	The zero based index of the output pin to retrieve the number of channels for the connected audio stream.	Indicates the number of channels for the output pin at the specified index (Applicable for audio streams only).
long	InBitsPerSample (long nPinIndex)	The zero based index of the input pin to retrieve the bits per sample value for the connected audio stream.	Indicates the bits per sample value for the input pin at the specified index. (Applicable for audio streams only).
long	OutBitsPerSample (long nPinIndex)	The zero based index of the output pin to retrieve the bits per sample value for the connected audio stream.	Indicates the bits per sample value for the output pin at the specified index. (Applicable for audio streams only).
long	InSamplesPerSec (long nPinIndex)	The zero based index of the input pin to retrieve the bits per sample value for the connected audio stream.	Indicates the samples per second (frequency) value for the input pin at the specified index. (Applicable for audio streams only).
long	OutSamplesPerSec (long nPinIndex)	The zero based index of the output pin to retrieve the bits per sample value for the connected audio stream.	Indicates the samples per second (frequency) value for the output pin at the specified index. (Applicable for audio streams only).
long	InputAspectRatioX (long nPinIndex)	The zero based index of the input pin for which to retrieve the X part of the aspect ratio for the connected video stream.	Indicates the X (width) part of the aspect ratio of the video stream at the specified index. (Applicable for video streams only).
long	InputAspectRatioY (long nPinIndex)	The zero based index of the input pin for which to retrieve the Y part of the aspect ratio for the connected video stream.	Indicates the Y (height) part of the aspect ratio of the video stream at the specified index. (Applicable for video streams only).
BSTR	InputPinStreamSubType (long nPinIndex)	The zero based index of the input pin to retrieve its stream sub type string.	Contains the stream sub type CLSID as a string. A note about BSTR properties

Interface Methods:

HRESULT CommitSettings ()

Description

Writes filter settings to the registry. The Multimedia filters save their settings to the registry only at filter destruction. This method will force the filter to save its settings to the registry before it is released. If the filter has no settings to write to the registry, E_NOTIMPL is returned.

Return

S_OK if connected, S_FALSE otherwise.

HRESULT ExportSettings (BSTR FileName)

Parameters

FileName

character string containing the destination file name.

Description

Writes filter settings to a file. The destination file can have one or more filters settings, where every filter is identified by its own section as follows:

[Filter 1]

Setting1=value

Setting(n)=value

[Filter m]

Setting1=value

Setting(n)=value

The file format is the same as windows INI.

If the filter has no settings to expose, E_NOTIMPL is returned.

Return

S_OK if connected, S_FALSE otherwise.

HRESULT ImportSettings (BSTR FileName)

Parameters

FileName

character string containing the source file name.

Description

Reads and sets filter settings from a file, written using the ExportSettings method. The ExportSettings method insures that the file is formatted correctly and the right values are written. If the filter has no settings to set, E_NOTIMPL is returned.

Return

S_OK if connected, S_FALSE otherwise.

HRESULT LoadFromMemory (char * pMem)

Parameters

pMem	pointer to a character string containing the filter settings to load.

Description

Reads filter settings from a memory buffer. The passed buffer must be filled using the WriteToMemory method.

Return

S_OK if connected, S_FALSE otherwise.

HRESULT LoadSettings ()

Description

Loads filter settings from the registry. The Multimedia filters import the settings from the registry only at creation time. This method will force the filter to re-load its settings from the registry. If the filter has no settings to load from the registry, E_NOTIMPL is returned.

Return

S_OK if connected, S_FALSE otherwise.

HRESULT CommitSettings ()

Description

Writes filter settings to the registry. The MM filters save their settings to the registry only at filter destruction. This method will force the filter to save its settings to the registry before its released.

If the filter has no settings to write to the registry, E_NOTIMPL is returned.

Return

S_OK if connected.

HRESULT WriteToMemory (char * pMem, long *lSize)

Parameters

pMem	pointer to a character string to be updated with the filter settings.
lSize	pointer to a variable to be updated with the size of the written settings, in bytes.

Description

Writes filter settings to a memory buffer. The filter settings will be written in binary format. Do not try to read individual settings from the buffer. The output buffer can only be used with the LoadFromMemory method.

Return

S_OK if connected, S_FALSE otherwise.