I'm looking to build some code that can listen to a song playing through an app like Spotify and detect its BPM (beats per minute). I want to either display this information to the user or use it as part of a larger program later on. I have a solid grasp of Python and have explored a few other programming languages as well, so if there's a need to use something different, I'm open to that too! Any suggestions?
6 Answers
Consider looking into this site: tunebat.com. It might give you some insights or tools to scrape BPM data.
My first thought is that using a Fast Fourier Transform (FFT) could help, though I've never actually implemented one myself. There are libraries that can simplify this, so maybe look for those.
This task can be trickier than it seems! The concept of a beat varies a lot between different music genres. If I were tackling this, I'd consider using supervised machine learning. You could gather songs with known BPMs and train a model using clips from those tracks, aiming to predict the BPM from new inputs. Just keep in mind, accuracy may drop depending on the diversity of genres you include.
Honestly, I'd recommend not reinventing the wheel unless your goal is to really dive into the mechanics. Check out aubio.org; it's a library in C but has a Python module that you can easily use for BPM detection.
Using FFT with libraries like NumPy, you can analyze audio and spot rhythmic cycles in the lower frequencies, especially with bass and drums. Start with a low-pass filter before applying FFT to focus on sound energy spikes. If you want to get fancy, you could employ comb filters to check your BPM guesses against the audio signal for stronger beats.
You'll want to check if there's a library out there that can handle BPM detection for you. If you're familiar with Digital Signal Processing (DSP), that could also be helpful, but leveraging existing libraries will save you a lot of time.
DSP? What does that involve?
There's a library called "kiss_fft" which is really effective for implementation in C. But honestly, unless you’re trying to learn the fundamentals, it’s better to use a library specifically designed for sound or signal processing.