When you don't have enough Music data from Bluetooth, OutputMixer goes Crasy!..

[Knottis]

ツ🎵 Hope someone can help me with this!

If you Start and Stop the Music too quickly (for example from Spotify) before or at the end of the Main loop, the OutputMixer goes into lock/crasy.
When you continues to play music again and adding more Bluetooth-Data then everything works as it should again!

How can I check that I have sufficient Music data stored in cache before running the Sin-frequency => Play(XX.YY) function!...
So that the OutputMixer does not stall!... (Should only play Note when I have music).

Have tested around a bit with: mixer.flushMixer();

---

#include <BluetoothA2DPSink.h>
#include <AudioConfig.h>
#include <AudioTools.h>

I2SStream OutI2S;
BluetoothA2DPSink a2dp_sink(OutI2S);

AudioInfo info(44100, 2, 16);
SineWaveGenerator<int16_t> sineWave(10000);
GeneratedSoundStream<int16_t> Sound(sineWave);
OutputMixer<int16_t> mixer(OutI2S, 2);

const int buffer_size = 128;
uint8_t sound_buffer[buffer_size];

//=================================================================
//                     Enough Bluetooth-Data ?..
//=================================================================
//  How to test that I have enough Bluetooth Data in Cache?...
//=================================================================
void Play(float frequency, int durationMs) {
  sineWave.setFrequency(frequency);
  delay(durationMs);
  sineWave.setFrequency(0);
}
//=================================================================

void Read_Data_Stream(const uint8_t *A2DPdata, uint32_t length) {
  // Write data to Mixer.
  // To keep the mixing buffer small we split up the output into small chunks
  int count = length / buffer_size + 1;
  for (int j = 0; j < count; j++) {
    const uint8_t *start = A2DPdata + (j * buffer_size);
    const uint8_t *end = min(A2DPdata + length, start + buffer_size);
    int len = end - start;
    if (len > 0) {
      // write a2dp
      mixer.write(start, len);
      // write sine tone with identical length
      Sound.readBytes(sound_buffer, len);
      mixer.write(sound_buffer, len);
    }
  }
}


void setup() {
  // Register data callback
  a2dp_sink.set_stream_reader(Read_Data_Stream, false);

  // Setup Output mixer with min necessary memory
  mixer.begin(buffer_size);   //  128

  // Update sample rate
  info.sample_rate = a2dp_sink.sample_rate();
  // Start sine wave
  sineWave.begin(info, 0);
  // Setup Output
  auto config = OutI2S.defaultConfig();
  config.copyFrom(info);
  // Configure I2S pins for the external DAC - PCM5102
  config.pin_data = 25;  // Data pin -> 25
  config.pin_bck = 32;   // Bit Clock pin
  config.pin_ws = 33;    // Word Select pin

  config.buffer_count = 4;
  config.buffer_size = buffer_size;  //  4*128=1024
  
  OutI2S.begin(config);

  // Start Bluetooth Audio
  a2dp_sink.start("BluetoothAudio", true);
}


//--------------------------------------------------------
//        If not enough Music data..."MAD-MAX..."
//--------------------------------------------------------
void loop() {
  Play(N_E5, 700);
  Play(N_CS5, 700);
  Play(N_A4, 700);
  delay(5000);
}
//--------------------------------------------------------