librosa.display.specshow does not display the correct time scale

When trying to display a chromagram using librosa.display.specshow, the time scale is not correct. The time scale is correct when the hop_length is its default value (512). However, it is incorrect whenever the hop_length is changed. (The input length increases as I increase the hop_length).

Code I used to generate and plot the chromagram:

# 512 is the default, when this number is altered, the time scale is wrong
HOP_SIZE = 512

y, sr = librosa.load(mp3)
chroma_feature = librosa.feature.chroma_stft(y=y, sr = sr, hop_length = HOP_SIZE)

fig, ax = plt.subplots()
img = librosa.display.specshow(chroma_feature, y_axis='chroma', x_axis='time', ax=ax, sr = sr, hop_length = HOP_SIZE)
fig.colorbar(img, ax=ax)
plt.show()

[clare228]

Thank you for the help and explanation! I tried the first option you suggested and it worked.

[bmcfee]

Glad to hear. I’ll leave this issue open so we can address it in the next major release.