win-capture-audio

win-capture-audio is an OBS Studio plugin that captures audio from a specific application — the same idea as OBS’s window/game capture, but for sound — so you can pull a game or app’s audio onto its own track without routing everything through virtual cables or a hardware mixer. Worth knowing: recent OBS versions ship a native “Application Audio Output Capture” source on Windows that covers the same need, so this plugin is mostly for older setups or cases the built-in source doesn’t handle. Free and open-source.