problem:

0 results with HM.f0Detection function (for some audio files)

I'm not sure if this is an issue, but I try to use HM.f0Detection to extract the fundamental frequency of music files, these include: 1 tone of a piano/guitar/bass_guitar, and the pitch can be clearly identified. The details of the problems are: for an audio file, I got results like np.array([0,0,0,0,0,0,0,0,440,0,0,0,440,440,441.2,440.2,0,0,0,0,0,0,0,0,0,0,]) There are just so many zeros that I don't want to expect. For some files, I got:
np.array([0,0,0,0,0,0,0,0,0,0,0,0,0,0]), which is basically all zeros...

How may I solve this? I have set the minf0 to 50 as this is also setted in the lecture videos, maxf0 to ~800. I am just not sure how to fix this problem.