[Hack&Lube]

The dragging thing you want to do is probably pretty much impossible to accomplish unless you an advanced software developer and also have a strong working knowledge of audio chipsets and drivers and can re-write them.

Some things that will work are:

1. You'll need two active sound devices. If your videocard has HDMI audio built in, that will suffice along with your built in soundcard. You'll need two separate media players (any combination of Media Player Classic, Media Player Classic Home Cinema, and VLC will do). You will need to modify the settings of these players so that they are permanently set to output to a specific device instead of default or system audio. Set one to your onboard sound, set one to HDMI audio. Only use one media player for your main monitor and use one media player for your TV. You can right click on videos before you start them to choose which to start from.

2. The other thing you can do is to create a keyboard macro or a windows shortcut activated via keystroke, icon, or macro when you launch an application or when you click on it to rapidly flip the default audio device back and forth between onboard (probably Realtek or whatever) and HDMI audio. I coded one back in Windows XP when I was using multiple soundcards to produce music but have completely forgotten how to do this in the intervening 10 years.

3. The simplest and dumbest layman's thing would be to output audio to both your PC speakers and TV at once (you'll need to probably use the extra mini jack lines from your onboard audio) and just turn on/off or mute your PC or your TV selectively.