Encrypt byte array, converting from string to 8bit integer array

I am trying to record audio raw data in python, ecrypt data and send it to .NET server where I decrypting received data and converting to byte array. When I converting received data to byte array like this Encoding.ASCII.GetBytes(decryptedData) everything is almost working. But maximum byte value is 63 and maximum byte value of sending data is 255. Example of sent and received data:

Sent data

3, 0, 3, 0, 3, 0, 4, 0, 4, 0, 2, 0, 252, 255, 1, 0, 255, 255, 1, 0, 0, 0...

Received data

3, 0, 3, 0, 3, 0, 4, 0, 4, 0, 2, 0, 63, 63, 1, 0, 63, 63, 1, 0, 0, 0...

When I converting received data to byte array like this Encoding.UTF8.GetBytes(DecryptData(aes, data)) everything is almost working. But high value is different. Example of sent and received data:

Sent data

6, 0, 8, 0, 250, 255, 255, 255, 3, 0, 6, 0, 2, 0, 4, 0, 3, 0, 6, 0, 3, 0...

Received data

6, 0, 8, 0, 239, 191, 189, 239, 191, 189, 239, 191, 189, 239, 191, 189, 3, 0, 6, 0, 2, 0, 4, 0, 3, 0, 6, 3, 0...

It seems like that converting generating more variables. I don't know.

Here is code of python of recording, encrypt and sending data:

import pyaudio
import sys
import socket
import struct
import base64
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad

key = b"bpjAqrgO2N8q7Rfj8IHzeRxmP1W4HwUTWCRi7DQgyDc="
iv = b"Ta6e1cZAWQMM0QI66JC74w=="

UDP_IP = "127.0.0.1"
UDP_PORT = 5005

chunk = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 2
RATE = 44100
RECORD_SECONDS = 5

pya = pyaudio.PyAudio()

stream = pya.open(format=FORMAT, channels=CHANNELS, rate=RATE, input=True, output=True, frames_per_buffer=chunk)

print ("recording")
for i in range(0, 44100 // chunk * RECORD_SECONDS):
    data = stream.read(chunk)
    print (struct.unpack('{}B'.format(len(data)), data))
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    cipher_suite = AES.new(base64.urlsafe_b64decode(key), AES.MODE_CBC, base64.urlsafe_b64decode(iv))
    cipher_text = cipher_suite.encrypt(pad(data, 16))
    sock.sendto(cipher_text, (UDP_IP, UDP_PORT))
    input ()
    # check for silence here by comparing the level with 0 (or some threshold) for 
    # the contents of data.
    # then write data or not to a file

print ("done")

stream.stop_stream()
stream.close()
pya.terminate()

Here is code of C# of receive, decrypt and convert data:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace DOTNETServer
{
    class Program
    {
        private static string IP = "127.0.0.1";
        private static int Port = 5005;
        private static string Key = "bpjAqrgO2N8q7Rfj8IHzeRxmP1W4HwUTWCRi7DQgyDc=";
        private static string IV = "Ta6e1cZAWQMM0QI66JC74w==";

        static void Main(string[] args)
        {
            UDPServer(IPAddress.Parse(IP), Port);
            Console.ReadKey();
        }

        private static void UDPServer(IPAddress IP, int Port)
        {
            byte[] data = new byte[32768];
            IPEndPoint endPoint = new IPEndPoint(IP, Port);
            UdpClient client = new UdpClient(endPoint);

            SymmetricAlgorithm aes = new AesManaged();
            aes.KeySize = 256;
            aes.Key = Convert.FromBase64String(Key);
            aes.IV = Convert.FromBase64String(IV);

            while (true)
            {
                Console.WriteLine("Waiting for data.");
                data = client.Receive(ref endPoint);
                var convertedReceivedData = Encoding.ASCII.GetBytes(DecryptData(aes, data));
                Console.Write("(");
                foreach(var item in convertedReceivedData)
                {
                    Console.Write(item + ", ");
                }
                Console.Write(")");
            }
        }

        static byte[] EncryptText(SymmetricAlgorithm aesAlgorithm, string text)
        {
            ICryptoTransform encryptor = aesAlgorithm.CreateEncryptor(aesAlgorithm.Key, aesAlgorithm.IV);
            byte[] data = new byte[32768];
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter writer = new StreamWriter(cs))
                    {
                        writer.Write(text);
                    }
                }
                data = ms.ToArray();
            }

            return data;
        }

        static string DecryptData(SymmetricAlgorithm aes, byte[] data)
        {
            ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
            byte[] encryptedDataBuffer = data;
            string plainText = "";
            using (MemoryStream ms = new MemoryStream(encryptedDataBuffer))
            {
                using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader reader = new StreamReader(cs))
                    {
                        plainText = reader.ReadToEnd();
                    }
                }
            }

            return plainText;
        }
    }
}