What is *required* to change the file I'm streaming from?

[ITServ-DE]

Hello everybody, and thank you for reading.

I'm building kind of a Jukebox, where I have buttons for each song. When I press a button, the corrosponding audio is played.

I now wonder what actually needs to be restarted when I change the file. At the moment, I end the copier, close and reopen the file, and restart the copier, but is there a better way to change the file I want to stream?

Here is the sample code:

#include "LittleFS.h"
#include "AudioTools.h"
#include "AudioLibs/A2DPStream.h"

const int SongOne = 18;  //  pushbutton pin for song 1
const int SongTwo = 19;  // pushbutton pin for song 2
const int SongThree = 21;  //  pushbutton pin for song 3

int song_to_play=0;
int song_playing=0;

File audioFile;
A2DPStream a2dpStream;      // access A2DP as stream
StreamCopy copier;          // copy audioFile to a2dpStream

void setupBT(){
    // start bluetooth
    Serial.println("starting A2DP...");
    auto cfgA2DP = a2dpStream.defaultConfig(TX_MODE);
    cfgA2DP.name = "SR-B7";
    cfgA2DP.auto_reconnect = true; 
    a2dpStream.begin(cfgA2DP);
    // set intial volume
    a2dpStream.setVolume(0.7);
}

void setupButtons(){
  pinMode(SongOne, INPUT_PULLUP);
  pinMode(SongTwo, INPUT_PULLUP);
  pinMode(SongThree, INPUT_PULLUP);
}

void setup() {
  // put your setup code here, to run once:

    Serial.begin(115200);
    AudioLogger::instance().begin(Serial, AudioLogger::Warning);

    setupButtons();
    setupBT();
    
    if(!LittleFS.begin()){
      Serial.println("An Error has occurred while mounting LittleFS");
      return;
    }
}

void loop() {
  // put your main code here, to run repeatedly:
  copier.copy();
    
  song_to_play = (!digitalRead(SongOne) * 1 ) + (!digitalRead(SongTwo) * 2 ) + (!digitalRead(SongThree) * 3 ) ;
  
  if ((song_playing != song_to_play) && (song_to_play != 0)) {
    song_playing = song_to_play;
    Serial.println(song_to_play);
    
    copier.end();
    audioFile.close(); 

    switch (song_to_play){
      case 1:
        audioFile = LittleFS.open("/1.raw");
        break;
      case 2:
        audioFile = LittleFS.open("/2.raw");
        break;
      case 3:
        audioFile = LittleFS.open("/5.raw");
        break;
    }
    
    if (!audioFile) {
      Serial.println("Failed to open file.");
    } else {
      Serial.println ("File successfully opened");
    }

    copier.begin(a2dpStream,audioFile);
  }

}

In addition to that, I run into a problem: if I trigger button 2 and, while playing, immediately button 1, the ESP starts to stream noise only. I suspect the queue or shared memory gets polluted somehow. It also does not recover from that situation. Any idea what I could do against this?

Thank you for your advice.

[pschatzmann]

It should be good enough to close the last file and continue to copy data from the next file.
The copier.end() is currently not necessary as it just sets the from and to variables to zero, but it is a good habit to call end whenever you call begin...