IltmmConvert::GetPreferredFilter

#include "ltmm.h"

C Syntax

HRESULT IltmmConvert__GetPreferredFilter(pConvert, FilterType, pVal)

C++ Syntax

HRESULT GetPreferredFilter(FilterType, pVal)

 

IltmmConvert *pConvert;

/* pointer to an interface */

long FilterType

/* value of a filter type */

BSTR *pVal;

/* pointer to a string */

Retrieves the preferred filter display name set using IltmmConvert::SetPreferredFilter.

Parameter

Description

pConvert

Pointer to an IltmmConvert interface.

FilterType

Value that indicates the type of filter. For a list of possible values, refer to lltmmConvert_PreferredFilter Constants.

pVal

Pointer to a string to be updated with the filter's display name. For a list of possible values, refer to ltmmFilter Constants.

Returns

S_OK

The function was successful.

<> S_OK

An error occurred. Refer to the Error Codes or the HRESULT error codes in the DirectShow documentation.

Comments

This method can be used to determine whether a preferred filter has been set by IltmmConvert::SetPreferredFilter. It will return NULL (if no preferred filter has been set) or a display name indicating the preferred filter.

A display name uniquely identifies a filter. Display names for filters have the following format: @device:sw:GUID\GUID.

For example, the display name for the LEAD MPEG2 Transport Demultiplexer is:

@device:sw:{083863F1-70DE-11D0-BD40-00A0C911CE86}\{E2B7DF1A-38C5-11D5-91F6-00104BDB8FF9}

Note that there is a single backslash between the two GUIDs. But if you enter this as a C/C++ string, you would need to use two backslashes since '\' is an escape character in C/C++ strings.

If the method succeeds, the caller must free the returned string by calling the SysFreeString function.

A list of display names for common LEAD filters can be found in ltmmFilter Constants.

Please see IltmmConvert::SetPreferredFilter for more information on filter display names.

Required DLLs and Libraries

LTMM

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Mobile

See Also

Elements:

IltmmConvert::SetPreferredFilter

Topics:

Multimedia Function Groups

 

ltmmFilter Constants

 

ltmmConvert_PreferredFilter Constants

Example

For a C++ example, refer to .IltmmConvert__SetPreferredFilter Example for C++