sending audio to mqtt broker through ESP8266 - c

Question

I'm trying to stream voice to the MQTT broker. I'm using esp8266(NodeMCU1.0) and it's ADC to sampling the audio signal at 4KHz and 8-bit PCM audio format. I used Pubsubclient.h library to publish audio packets to the broker but on the other side when I receive packets and play them I have the interrupted voice and I have a delay between playing packets as long as my buffer size. please help me to have continues voice.
I have 2 main problems:
1) delay between playing packets as long as my buffer size
example of what i received: ;D ;D ;D .....|||||..........|||||||...........|||||||||............||||||||
2) Quality of voice: I receive a noisy voice.
Please help me! Thanks.
#include <ESP8266WiFi.h>
#include <PubSubClient.h>
const char* ssid = "Knight";
const char* password = "****";
const char* mqtt_server = "104.21.218.224";
WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (4096)
int i;
byte voice[MSG_BUFFER_SIZE];
void setup_wifi() {
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
randomSeed(micros());
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
// Create a random client ID
String clientId = "ashkan";
// Attempt to connect
if (client.connect(clientId.c_str())) {
Serial.println("connected");
// Once connected, publish an announcement...
if (!client.publish("doorphone/connected", "true")) {
Serial.println("publish failed, either connection lost, or message too large");
}
else {
Serial.println("publish succeeded");
}
// ... and resubscribe
// client.subscribe("doorphone/open");
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void setup() {
pinMode(BUILTIN_LED, OUTPUT); // Initialize the BUILTIN_LED pin as an output
Serial.begin(115200);
setup_wifi();
client.setServer(mqtt_server, 1883);
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
for (i = 0; i < MSG_BUFFER_SIZE; i++) {
voice[i] = analogRead(A0);
// client.write(voice[i]);
delayMicroseconds(125);
}
client.publish("doorphone/connected", voice, MSG_BUFFER_SIZE);
}