[FEATURE REQUEST] Separate Audio Tracks, Custom FPS/Resolution and Instant Replay without needing to clip manually

[nether portal]

So far I've really enjoyed the Steam game recording system but one thing I just didn't understand why they weren't integrated features were the ability to separate audio tracks (either from individual applications or multiple audio sources) or being able to use a Keybind to record a specific set of time (Similar to what nVidia does with its instant replay system) without having to manually trim down the clip. You can't even pick at what FPS or Resolution you want for your recordings

So far the steam game recording feature has great potential but I believe that with these features, it would be a better alternative than the currently available shadowplay systems