Click / pop , once in a while at the beginning of fileloop stream, wav encoder

[KatePimbleton]

Hello,
I'm encountering an issue when playing wav files, once in a while a pop sounds
appear at the very beginning. The beginning of the file is silence though.

I'm starting this discussion after going through wiki , documentation & discussion board, but there's something I'd like
to try and failed to implement myself, in the following code, I would like the volume to raise a few millisecond
after I start playing the file.

I looked into the way "fade" is implemented in the audioplayer, but failed at implementing it in Fileloop.
Maybe I don't need to fade in, but just wait for some time after I start playing the file.

here's the code I've come up with, any help at using the volume to raise after the file is started is welcome:

#define LoRa_frequency 433E6
#define UNUSE_PIN (0)
#define RADIO_SCLK_PIN 5
#define RADIO_MISO_PIN 19
#define RADIO_MOSI_PIN 27
#define RADIO_CS_PIN 18
#define RADIO_DIO0_PIN 26
#define RADIO_RST_PIN 23
#define RADIO_DIO1_PIN 33
#define RADIO_BUSY_PIN 32

#include <LoRa.h>

#include "AudioTools.h"
#include "AudioCodecs/CodecWAV.h"
#include "AudioLibs/FileLoop.h"
#include "AudioLibs/AudioSourceSD.h"
#include <SPI.h>
#include <SD.h>
#include "FileLister.h"
#include <Arduino.h>
#include <Wire.h>

#define initPMU()
#define disablePeripherals()
int currentTrack = 0;
unsigned long lastTime = 0;
int inBytes = 0;
int lastInBytes = 0;
int counter = 0;

FileLister fileLister;
int *fileCounts = fileLister.getFileCounts();
int folderIndex = 0;
char MAC[23];
int id = -1;

SPIClass SDSPI(HSPI);
I2SStream i2s;
const char *startFilePath = "/";
const char *ext = "wav";
VolumeStream volume(i2s);
EncodedAudioStream decoder(&volume, new WAVDecoder());
FileLoop loopingFile;
StreamCopy copier(decoder, loopingFile);

void initBoard() {
Serial.println("initBoard");
SPI.begin(RADIO_SCLK_PIN, RADIO_MISO_PIN, RADIO_MOSI_PIN);
}
void setup() {
Serial.begin(115200);
initBoard();
delay(1500);
int folderCount = fileLister.readDirectoriesAndFiles();
printList();
snprintf(MAC, 23, "%llX", ESP.getEfuseMac());
Serial.println("LoRa Receiver");
Serial.println(MAC);
LoRa.setPins(RADIO_CS_PIN, RADIO_RST_PIN, RADIO_DIO0_PIN);
if (!LoRa.begin(LoRa_frequency)) {
Serial.println("Starting LoRa failed!");
while (1) ;
}
LoRa.setTxPower(20);
//AudioLogger::instance().begin(Serial, AudioLogger::Info);
auto cfg = i2s.defaultConfig(TX_MODE);
cfg.pin_bck = 4;
cfg.pin_ws = 12;
cfg.pin_data = 25;
i2s.begin(cfg);
volume.begin(cfg);
volume.setVolume(1);
decoder.begin();
Serial.println(fileCounts[0]);
// handlePlayFile(0, 1);
}
void loop() {
copier.copy();

int packetSize = LoRa.parsePacket();
if (packetSize) {
String recv = "";
while (LoRa.available()) {
char c = LoRa.read();
if (c == ' ') {
break;
} else {
recv += c;
}
}
recv.trim();
if (recv == "t") {
handlePlayFile(1, 0);
} else if (recv == "l") {
loopingFile.end();
currentTrack = 0;
} else if (recv == "s") {
if (!copier.copy()) {
handlePlayFile(0, currentTrack);
} else if (copier.copy()) {
volume.setVolume(0);
loopingFile.end();
currentTrack = (currentTrack + 1) % fileCounts[0];
}
}
}
}
void handlePlayFile(int folderIndex, int fileIndex) {
loopingFile.setLoopCount(0);
String filePath = fileLister.getFilePath(folderIndex, fileIndex);
File wavFile = SD.open(filePath);
loopingFile.setStartPos(44);
loopingFile.setFile(wavFile);
volume.setVolume(1);
}

Cheers