test.webrtc.org use firefox2 to open http://test.webrtc.org then click Right-top: START, will get below: Then to disable the playback device...
how to build Mozzila Firefox on Windows https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Windows_Prerequisites Please follow the above link carefully, you can make it. Enjoy and hope you have a good performance...