code:

import os
import time

with open("output.txt", "w") as out:
    print("Instrument time per sample", file = out)

dirs = next(os.walk("."))[1]
for user in dirs:
    samples = next(os.walk(user))[1]
    for sample in samples:
        path = user + "/" + sample + "/frames"
        files = next(os.walk(path))[2]
        new = 0
        old = 0
        for file in files:
            fileTime = os.path.getctime(path + "/" + file)
            if old == 0:
                old = fileTime
            if fileTime < old:
                old = fileTime
            if fileTime > new:
                new = fileTime
        date = time.strftime("%Y-%m-%d", time.localtime(old))
        diff = round(new - old)
        minute, second = divmod(diff, 60)
        hour, minute = divmod(minute, 60)
        with open("output.txt", "a") as out:      
            print("%s\t%s\t[%s]\t%02d:%02d:%02d" %
                (user, sample, date, hour, minute, second), file = out)