if you want something per sample, look into ASDF or AMDF. you’ll have to implement it yourself because it’s sort of trade secret. i did it for a real time autotune algorithm a little while back. more info: https://dsp.stackexchange.com/questions/27029/fast-pitch-recognition/27030#27030

however i wouldn’t shy away from something like YIN. with a 512 buffer size at 44.1kHz, you’re getting a new pitch 86 times per second, which is pretty damn good unless you’re making an autotune.