why the recording file is empty in python - python-3.x

Question

I am trying to record my desktop screen and record the audio from microphone simentensously with the help of this python script.
Now when i run only the screen capture part the code works perfectly fine but when i try to run both sound recording and screen capture combine code as shown in below code. my video and audio both file does not open. (0 bytes) or very less size file.
How can i solve this problem.
updated Code
now i am able to record voice properly but the video file is not opening?
import datetime
import tkinter as tk
from tkinter import *
from tkinter import ttk ,FLAT
from PIL import Image, ImageTk, ImageGrab
import cv2
import numpy as np
import threading
import win32api
import pyaudio
import wave
VIDEO_SIZE = (800 , 420) #(960, 540)
p = ImageGrab.grab()
a, b = p.size
chunk = 1024
sample_format = pyaudio.paInt16
channels = 2
fs = 44100
frames = []
g = pyaudio.PyAudio()
date = datetime.datetime.now()
filename='rec_%s-%s-%s-%s-%s-%s.mp4' % (date.year, date.month, date.day,date.hour, date.minute, date.second)
#fourcc = cv2.VideoWriter_fourcc(*'XVID')
frame_rate = 24
cap = cv2.VideoCapture(0)
out = cv2.VideoWriter()
def screen_capturing():
global capturing
capturing = True
while capturing:
img = ImageGrab.grab()
frame = np.array(img)
sc = np.array(img)
_xs,_ys = win32api.GetCursorPos()
cv2.circle(frame,(_xs,_ys),20,(255,255,0), 2)
sc = cv2.resize(sc, VIDEO_SIZE)
tkimage.paste(Image.fromarray(sc))
frame = cv2.cvtColor(frame, cv2.COLOR_RGB2BGR)
out.write(frame)
def start_screen_capturing():
if not out.isOpened():
out.open(filename, 0x31637661, frame_rate,(VIDEO_SIZE))
t1=threading.Thread(target=screen_capturing, daemon=True)
t1.start()
def stop_screen_capturing():
global capturing
capturing = False
out.release()
def voice_recording():
global recording
while recording:
data = stream.read(chunk)
frames.append(data)
def start_voice_recording():
global stream
stream = g.open(format=sample_format,channels=channels,rate=fs,frames_per_buffer=chunk,input=True)
global recording
recording = True
print('capturing')
t2 = threading.Thread(target=voice_recording) # daemon=True
t2.start()
def stop_voice_recording():
#global recording
recording =False
print(' complete')
filename='test'
filename = filename+".wav"
wf = wave.open(filename,'wb')
wf.setnchannels(channels)
wf.setsampwidth(g.get_sample_size(sample_format))
wf.setframerate(fs)
wf.writeframes(b''.join(frames))
wf.close()
root = tk.Tk()
root.title('Screen Recorder')
root.geometry('+260+70')
tkimage = ImageTk.PhotoImage(Image.new('RGB', VIDEO_SIZE, (0,0,0)))
w, h = VIDEO_SIZE
vbox = tk.Label(root, image=tkimage, width=w, height=h, bg='black')
vbox.pack(pady=10,padx=25)
frame = tk.Frame(root)
frame.pack()
start_cap = tk.Button(frame, text='Start screen Recording', width=30, command=start_screen_capturing)
start_cap.grid(row=0, column=0)
stop_cap = tk.Button(frame, text='Stop screen Recording', width=30, command=stop_screen_capturing)
stop_cap.grid(row=0, column=1)
start_voice = tk.Button(frame, text='Start voice Recording', width=30, command=start_voice_recording)
start_voice.grid(row=0, column=2)
stop_voice = tk.Button(frame, text='Stop voice Recording', width=30, command=stop_voice_recording)
stop_voice.grid(row=0, column=3)
root.mainloop()