How to resample timedeltas?

You can use groupby with time // period to do this:

import pandas as pd
import numpy as np

t = np.random.rand(10000)*3600
t.sort()
v = np.random.rand(10000)

df = pd.DataFrame({"time":t, "value":v})

period = 5*60
s = df.groupby(df.time // period).value.mean()
s.index *= period