How to act as a microphone using DirectShow or something else on windows?

I have googled for a while to find how to create a virtual mic on windows. But I find nothing.

I want to write a program acting as a microphone which can be used in Skype when there is no mic on my computer. So that I can play music from audio files to my friends.

Is it realizable? Can I do it in C++?

If so, Can I do it in directshow? Which Interface should I implement to make a virtual mic filter. Otherwise, what oth开发者_StackOverflow社区er technology should I study?

If not, why?

TIA!

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Maybe something like this is what you want?

http://software.muzychenko.net/eng/vac.htm

Also a related question on super user.

https://superuser.com/questions/190093/how-to-play-mp3-files-into-the-microphone-input