Hey Dusan Sifra ,
What type of music are you referring? If you are attempting to capture an application that is playing music on your computer, you would likely be doing so with the system audio capture. The problem here is that this will capture the entire audio from your computer. We currently do not have the ability to capture application specific audio.
I will normally use the line in on my computer and plug my phone in via an aux cord which I can then capture via Gameshow.