Hop size in STFT

1. What is hop size in STFT?
2. How do I choose a hop size?
3. What is hop length in Librosa?
4. How is STFT different from FFT?

What is hop size in STFT?

Short time Fourier Transform and Spectrogram

Window length is the length of the fixed intervals in which STFT divides the signal. Hop length is the length of the non-intersecting portion of window length. Overlap length is the length of the intersecting portion of the window length.

How do I choose a hop size?

Hop size should refer to the number of samples in between successive frames. For signal analysis Hop Size should be less than the frame size, so that frames overlap.

What is hop length in Librosa?

The default frame and hop lengths are set to 2048 and 512 samples, respectively.

How is STFT different from FFT?

If you look closely, there is a difference in the time frame on 3D graphs between STFT and FFT. STFT has smaller time frames, consequently, the frequency spectrum moves smoother over time, therefore it is more accurate. Block size - defines the number of real data samples to be taken for the calculating FFT.