lots of loss

[fensoft]

conditions:

• 1m away from my router
• using localhost mp3 through python3 -m http.server

results: lots of jittering.

actions tried:

• increase esp32 cpu frequency
• increase AudioFileSourceBuffer buffer size
• increase AudioOutputI2S dma_buffer
• set channel to mono
  but no change

here is my code:

#include <Arduino.h>
#include <WiFi.h>
#include "AudioFileSourceICYStream.h"
#include "AudioFileSourceBuffer.h"
#include "AudioGeneratorMP3.h"
#include <AudioOutputI2S.h>
#include "pins.h"

#ifndef STASSID
#define STASSID "wifi_wpa2"
#define STAPSK  "<password>"
#endif

const char* ssid = STASSID;
const char* password = STAPSK;

AudioGeneratorMP3 *mp3;
AudioFileSourceHTTPStream *file;
AudioFileSourceBuffer *buff;
AudioOutputI2S *out;

// Called when there's a warning or error (like a buffer underflow or decode hiccup)
void StatusCallback(void *cbData, int code, const char *string)
{
  const char *ptr = reinterpret_cast<const char *>(cbData);
  // Note that the string may be in PROGMEM, so copy it to RAM for printf
  char s1[64];
  strncpy_P(s1, string, sizeof(s1));
  s1[sizeof(s1)-1]=0;
  Serial.printf("STATUS(%s) '%d' = '%s'\n", ptr, code, s1);
  Serial.flush();
}


void setup()
{
  Serial.begin(115200);
  delay(1000);
  Serial.println("Connecting to WiFi");

  WiFi.disconnect();
  WiFi.softAPdisconnect(true);
  WiFi.mode(WIFI_STA);
  
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    Serial.println("...Connecting to WiFi");
    delay(1000);
  }
  Serial.println("Connected");
  Serial.println((int)getCpuFrequencyMhz());

  audioLogger = &Serial;
  file = new AudioFileSourceHTTPStream("http://localip/file.mp3");
  file->useHTTP10();
  buff = new AudioFileSourceBuffer(file, 8192);
  buff->RegisterStatusCB(StatusCallback, (void*)"buffer");
  out = new AudioOutputI2S(0, 0, 32);
  out->SetChannels(1);
  out->SetOutputModeMono(true);
  out->SetPinout(BCK, WS, DOUT);
  mp3 = new AudioGeneratorMP3();
  mp3->RegisterStatusCB(StatusCallback, (void*)"mp3");
  mp3->begin(buff, out);
}


void loop()
{
  static int lastms = 0;

  if (mp3->isRunning()) {
    if (millis()-lastms > 1000) {
      lastms = millis();
      Serial.printf("Running for %d ms...\n", lastms);
      Serial.flush();
     }
    if (!mp3->loop()) mp3->stop();
  } else {
    Serial.printf("MP3 done\n");
    delay(1000);
  }
}

[fensoft]

Looks like the file is the reason but I don't know why:

ok.mp3: MPEG ADTS, layer III, v1, 128 kbps, 44.1 kHz, JntStereo
bad.mp3: Audio file with ID3 version 2.3.0, contains: MPEG ADTS, layer III, v1, 64 kbps, 44.1 kHz, Stereo