My 08 Bullitt's factory exhaust system seems to have developed a strange sound which I recorded in the video link below. Any suggestions on what may be causing this are greatly appreciated. Youtube link below because I couldn't figure out how to directly embed a video. Apologies if I broke a forum rule by doing this.

You'll hear the main exhaust sound but there is this secondary sound that sounds like a rapid putt-putt sound which is constant. Hard to pinpoint the sound but it seems to emanate from under the car somewhere around where driver and front passenger seats are...so not towards the axle backs.

Also about halfway through video you'll hear what sounds like a compressor kicking on and I think that's my AC going south on me. It makes that intermittent on-off sound whenever the AC is on. Don't think it ever sounded like that or that loud before.