I understand capture devices can show up twice in DirectShow. For example, if I have a microphone KS filter and muxed line-in/microphone KS filter, I get five DirectShow filters: http://blogs.msdn.com/b/matthew_van_eerde/archive/2010/12/18/10014843.aspx -- Audio Capture Sources ({33D9A762-90C8-11D0-BD43-00A0C911CE86}) -- Front Microphone (High Definiti Line In (High Definition Audio Rear Microphone (High Definitio ... -- WDM Streaming Capture Devices ({65E8773D-8F56-11D0-A3B9-00A0C9223196}) -- HD Audio Microphone HD Audio Muxed capture That said, I believe it's normal and expected behavior for DirectShow to sometimes insert software format conversion and to sometimes not. (I don't consider myself a DirectShow guru; perhaps this question should go to http://social.msdn.microsoft.com/Forums/en/windowsdirectshowdevelopment/threads ) Can you clarify why it is a problem for a format converter to be inserted above you? From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Matt Gonzalez Sent: Friday, November 2, 2012 3:59 PM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: AVStream Audio Frustration Hello Tim, I share your frustration; since Windows Vista, the new architecture caches the audio format in the registry and frequently ignores the capabilities reported by the driver. Have you tried KSEVENT_PINCAPS_FORMATCHANGE? It's only supported on Windows 7, but that may be what you're looking for. Cheers, Matt On 11/2/2012 3:54 PM, Tim Roberts wrote: What I'm saying is that I am pretty well convinced this is not a problem in my filter. I'm doing the right thing, in AVStream terms. In the sysaudio/waveIn case, someone above me is deciding what my default audio format is, and caching that information without consulting me, and without considering that my capabilities might change over time. That's what I need to nail down. -- Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx> Providenza & Boekelheide, Inc.