When creating the rhythm mechanics, I tried using Microsoft’s system timer and calculating bpm in milliseconds. Due to the physical limitation of storing floating point numbers, the input buffers fell out of sync after some time.

 

I investigated other solutions such as an FFT to extract peaks from the kick and snare, however this would place constraints on the music making process. I landed on using XAudio2 which allowed me to create my own audio buffer. This way I could simply get the total sample count of the audio file and perform logic using that number to create a timer that is synced with the playback of the music.

 

With access to the buffer, I had complete control over how big of a window players must input on beat, down to a 41000th of a second or whatever I chose the sample rate of my audio to be.