[Musicians] Anyone know of a real-time tempo (BPM) detector for Mac?

Folks, Do any of you know of a program will run on a MacBook (under OS X), listen to music through the built-in microphone, and automatically detect and display the tempo in beats per minute (of course occasionally updating the displayed number if the music speeds up or slows down)? Please note the specifics of my question and don't tell me that I ought to be asking about an app that will run on, say, a phone or tablet under iOS or Android. If you can recommend something that runs on a MacBook with OS X and you happen to mention that there are also iOS or Android or Windows versions of the same product, that's fine. But I mainly want something for a MacBook. Similarly, if whatever product you mention is also able to do batch processing and produce tempo profiles from MP3 files, WAV files, iTunes folders, URLs of YouTube videos, or whatever, that would be nice to know, but I'm mainly interested in something that can detect and display tempo by listening in real time (and without needing the user to tap along with the beat). I'd also be interested in knowing if the program could write updates of the current tempo to a place where they could periodically be read by some other process, such as a shell script, Python script, Java or C program, etc. Thanks. --Jim