record audio samples via alsaaudio for the ASSOS project - creates bad chunks of data

config.py

### configuration file for assos_listen
# upload
upload = False

# config for this sensor
sensorID = "al_03"

# sampling rate & chunk size
chunkSize = 1024
samplingRate = 44100 #44100 # 44100 needed for Aves sampling
# choices=[4000, 8000, 16000, 32000, 44100] :: default 16000

# sample length in seconds
sampleLength = 10

# configuration for assos_store container
ftp_server_ip = "192.168.0.157"
username = "sensor"
password = "sensor"

# storage on assos_listen device
storagePath = "/home/pi/assos_listen_pi/storage/"

recordAudioSamples_alsaaudio.py

import wave
import datetime
import signal
import ftplib
import sys
import os


#### alsaaudio since pyaudio gave IOError: [Errno Input overflowed] -9981
import alsaaudio   
import numpy as np
import array
import time
# configuration for assos_listen
import config


# run the audio capture and send sound sample processes
# in parallel
from multiprocessing import Process

# CONFIG
# Set attributes: Mono, 16 bit little endian samples
FORMAT = alsaaudio.PCM_FORMAT_S16_LE
CHANNELS = 1
# read from config.py
CHUNK = config.chunkSize
RATE = config.samplingRate
RECORD_SECONDS = config.sampleLength

# HELPER FUNCTIONS

# write to ftp
def uploadFile(filename):

    print("start uploading file: " + filename)
    # connect to container
    ftp = ftplib.FTP(config.ftp_server_ip, config.username, config.password)

    # write file
    ftp.storbinary('STOR '+filename, open(filename, 'rb'))
    # close connection
    ftp.quit()
    print("finished uploading: " +filename)


# write to sd-card
def storeFile(filename,recorder,frames):

    print("writing file: " + filename)
   
    wf = wave.open(filename, 'wb')
    wf.setnchannels(CHANNELS)
    wf.setsampwidth(2)
    wf.setframerate(RATE)
    wf.writeframes(frames)
    wf.close()
    
    #print(filename + " written")


# abort the sampling process
def signal_handler(signal, frame):
    print('You pressed Ctrl+C!')

    sys.exit(0)

# MAIN FUNCTION
def recordAudio(recorder):

    sampleNumber = 0
    while (True):
        
        sampleNumber = sampleNumber +1
        print("***  recording #" + str(sampleNumber))

        # %Y-%m-%d_%H%M%S_%Z is the by monitoR used time.source formatting
        # UTC is the default timezone
        # ___%f could be usefull for localisation algorithms
        startDateTimeStr = datetime.datetime.now().strftime("%Y-%m-%d_%H%M%S_UTC--%f")
        fileName =  str(config.sensorID) + "_" + startDateTimeStr + ".wav"

        wf = wave.open(fileName, 'w')
        wf.setnchannels(CHANNELS)
        wf.setsampwidth(2)
        wf.setframerate(RATE)

        for i in range(0, 1000*RECORD_SECONDS/22):
            
            l, data = recorder.read()
            wf.writeframes(data)

        wf.close()
        print(fileName + " written")

        if (config.upload == True):
            # since waiting for the upload to finish will take some time
            # and we do not want to have gaps in our sample
            # we start the upload process in parallel
            print("start uploading...")
            uploadProcess = Process(target=uploadFile, args=(fileName,))
            uploadProcess.start()



# ENTRYPOINT FROM CONSOLE
if __name__ == '__main__':

    recorder = alsaaudio.PCM(type=alsaaudio.PCM_CAPTURE)
    recorder.setchannels(CHANNELS)
    recorder.setrate(RATE)
    recorder.setformat(FORMAT)
    recorder.setperiodsize(CHUNK)

    # directory to write and read files from
    os.chdir(config.storagePath)

    # abort by pressing C
    signal.signal(signal.SIGINT, signal_handler)
    print('\n\n--------------------------\npress Ctrl+C to stop the recording')

    # start recording
    recordAudio(recorder)

For an example of a file with bad chunks see: https://drive.google.com/file/d/1LemPtyblKuZ-0ExHZCrbmFWE-JvhDKJi/view?usp=sharing
The error is not following any kind of schema. These are the four sensors I used to capture audio data and the erroneous files: https://drive.google.com/file/d/1Qkw4rbZ_GT-3RrFOqrFXX2uw6JUuUAzl/view?usp=sharing