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DirectShow Frequently Asked Questions

Below are answers to some questions that get asked repeatedly in the public forums.  If you don't find the answer you're looking for, see the Where to Get Help page.  The questions are divided into these categories:

 

General

Q.  I installed the DirectX SDK and there are no DirectShow headers or samples and I can't find the dshow docs in the CHM file.  Where are they?

Q.  Where  is DirectShow and what is its future?  (you may have read that it is legacy component)

Q.  What components of dshow, MF and WM are available in managed languages like C# and VB.NET?

Q.  Why do you use The March Hare instead of your real name?

 

Filter programming

Q.  Is there a wizard for creating dshow filters?

Q.  How can I avoid problems releasing objects?  Or, what are CComPtr and CComQIPtr and why should I use them?

 

Capturing

Q.  Why am I having problems getting two DV camcorders to work on the same FireWire (IEEE 1394) card?

Q.  Is there a standard way to set properties on a capture device such as resolution and exposure?

 

Rendering

Q.  What are the standard video renderers available in dshow?

Q.  Tell me more about VMR7.  It's the default in XP?  You said it's available in w2k?

Q.  What are the differences between the VMR7 and VMR9?

 

Compiling, linking and registering

Q.  Why am I getting undefined symbol errors from the linker that are in the baseclasses?

Q.  Is Visual Studio 6 (VC6) supported?

Q.  Is Visual Studio 2005 (VC8) supported?

Q.  The release notes for the February 2005 SDK Update say that Windows 2000 is not longer supported.  Can I still develop on w2k?

Q.  I am having problems compiling or linking.   Do you have any general advice?

Q.  I am getting undefined or multiply defined CLSIDs when I try to link.  How can I fix this?

Q.  I added <vmr9.h> to my project and now I'm getting lots of compile errors.  What's wrong?

Q.  What's the best way to register my filter using Visual Studio?

 

Debugging

Q.  Can I look at the filter graph from my application in GraphEdit?

Q.  Can I debug my filter in GraphEdit or another application?

Q.  What are the odd looking values (HRESULTs) returned by dshow methods?

Q.  Where is the dshow debug runtime and how do I install it?

 

Copyright © 2010 by The March Hare.  All Rights Reserved.  Last modified: August 07, 2010