audio (BluetoothA2DPSource) seems choppy

[tastewar]

Hi-

I am working from the basic-file_mps example (https://github.com/pschatzmann/arduino-audio-tools/blob/main/examples/examples-communication/a2dp/basic-file_mp3-a2dp/basic-file_mp3-a2dp.ino) and my code is nearly identical, with the exception of the speaker I am connecting to, the source file, and the fact that the file is stored in SPIFFS. The mp3 I am using is encoded at 128 k and is 40 s long (all I could fit on the device!).
Any strategies for reducing this? Here is the contents of the .ino file, and I could post a video on YouTube showing the effect if that would be helpful:

#include <AudioTools.h>
#include "BluetoothA2DPSource.h"
#include "SPIFFS.h"
#include "AudioTools/AudioLibs/A2DPStream.h"
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"

BluetoothA2DPSource a2dp_source;
File song;
MP3DecoderHelix mp3;
EncodedAudioStream decoder(&song, &mp3);

int32_t get_sound_data(uint8_t* data, int32_t size)
{
  delay(1); // feed the dog
  return decoder.readBytes((uint8_t*)data, size);
}

void setup()
{
  Serial.begin(115200);
  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);
  SPIFFS.begin();
  song = SPIFFS.open("/fb128s.mp3", "r");
  decoder.transformationReader().resizeResultQueue(1024 * 8);
  decoder.begin();
  a2dp_source.set_auto_reconnect(false);
  a2dp_source.set_data_callback(get_sound_data);
  a2dp_source.set_volume(50);
  a2dp_source.start("M3");
}

void loop()
{
  // to prevent watchdog in release > 1.0.6
  delay(1000);
}

[pschatzmann]

• Using a MemoryStream instead should remove quite some overhead.
• Or better just use an SD card to store the data: this gives you max 64GB!

[tastewar]

Thank you. I struggled for half an hour trying to understand why my compiled version didn't fit. I had even read your note, "After you generated the file you need to add the const qualifier to the generated array definition..." but I could have sworn I saw const in the file that was produced, and figured that xxd had been updated or something. Oops.