The only problem you'd run into if you decide to direct audio from your TV to your PC is that you'd need to position your PC speakers near your TV. Other than that, it should sound just fine if you don't mute line-in sounds.
I have it easy, since I only do Taiko no Tatsujin vids, so it's just a matter of laying an mp3 of the song over the video if the song isn't audible enough. |