IltmfConvert::SetPreferredMediaSourceHandler

Summary

Sets a preferred media source handler's GUID.

Syntax

#include "ltmf.h"

Platform Syntax
C HRESULT IltmfConvert_SetPreferredMediaSourceHandler(pConvert, MediaSourceHandlerType, Val)
C++ HRESULT SetPreferredMediaSourceHandler(MediaSourceHandlerType, Val)

Parameters

IltmfConvert *pConvert

Pointer to an IltmfConvert interface.

long MediaSourceHandlerType

Value that indicates the desired media source handler type. For a list of possible values, refer to ltmfConvert_PreferredMediaSourceHandler Constants.

BSTR Val

String that has the following possible values:

For a list of possible values, refer to ltmfMediaSourceHandler Constants.

Returns

Value Meaning
S_OK The function was successful.
<> S_OK An error occurred. Refer to the Error Codes or the HRESULT error codes in the MediaFoundation documentation.

Comments

By default, the toolkit creates media sources according to the default Media Foundation mechanism, and thats by using a Source Resolver which is standard way to create media sources. However, sometimes 3rd party media sources get installed on some computers and assigns their media source handler to a specific media type and are used instead of the media sources you shipped with your application. And unexpected problems can occur if these media sources are not working properly. The SetPreferredMediaSourceHandler method allows you to control which media sources are used in your application. You can decide to use a certain media source handler or you can choose to use only the LEAD ones.

Val is a string for the GUID of the media source handler. This GUID uniquely identifies the media source handler. Every media format has a registered media source handler(s) who are responsible of creating a media source for this media type.

For example, the GUID for the LEAD MPEG2 Transport Media Source Handler is:

EFE626C3-0A2C-49FA-8A01-3768B559B6DA

If the MediaSourceHandlerType argument is equal to ltmfConvert_PreferredMediaSourceHandler_Generic, then the possible values for Val are: ltmfMediaSourceHandler_LEADDefault or ltmfMediaSourceHandler_DontCare.

If ltmfMediaSourceHandler_LEADDefault is specified, then the LEAD default media source handlers will be set for ALL of the values listed in ltmfConvert_PreferredMediaSourceHandler.

If ltmfMediaSourceHandler_DontCare is specified, then the internal list of the preferred media source handlers will be cleared and the media source will be created using the Media Foundation's default mechanism (Source Resolver).

Use the ltmfMediaSourceHandler_XXX constants whenever possible. See ltmfMediaSourceHandler Constants for a list of predefined values.

Required DLLs and Libraries

Platforms

Win32, x64.

See Also

Functions

Topics

Example

For a C++ example, refer to .IltmfConvert::SetPreferredMediaSourceHandler Example for C++

Help Version 22.0.2022.6.24
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.

LEADTOOLS Media Foundation C API Help

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.