A client wanted to add SHOUTcast Radio to go along with his Ustream video broadcasting. This tutorial demonstrates that by using the audio device Stereo Mix, you can do a simulcast on a radio stream and video stream at the same time and be able to take calls. Radio directory Tune In does not accept streams from Ustream so the solution for those doing video streaming on Ustream is to add a radio stream.
What is not shown in this video is that whatever online phone device or software you are using; you must set the microphone setting to use Stereo Mix. Usually, if you set your audio card so that only Stereo Mix is enabled, then start or open the online phone system you use, it should automatically detect your audio settings as Ustream automatically detected our settings in the tutorial video.
This is not the only way to do this type of simulcasting. I am sure you can mix audio with your video using an external mixing device. However, we do not use external mix devices so we cannot help you with any issues that might arise. Please refer to your mixing device manual or call the company that makes your device.