AudioTools: Using Multiple Decoders

In all my demo sketches so far, I have used just one decoder only, but what if we want to play multiple audio file types ?

To support this scenario, I decided to provide the MultiDecoder class, that lets you register your codecs with the corresponding mime type.

This class works together with my MimeDetector which detects the file type based on the first couple of bytes.

Here is an example sketch that can play aac, mp3 and wav files from the SD drive:

#include "AudioTools.h"
#include "AudioTools/AudioLibs/AudioBoardStream.h"
#include "AudioTools/AudioLibs/AudioSourceSD.h" // or AudioSourceIdxSD.h
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"
#include "AudioTools/AudioCodecs/CodecAACHelix.h"

const char *startFilePath="/multi";
const char* ext="";
AudioSourceSD source(startFilePath, ext, SS);
I2SStream i2s;
MultiDecoder multi;
MP3DecoderHelix mp3;
AACDecoderHelix aac;
WAVDecoder wav;
AudioPlayer player(source, i2s, multi);

void setup() {
  Serial.begin(115200);
  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);

  // optionally define you custom pins for the SD drive
  // SPI.begin(PIN_AUDIO_KIT_SD_CARD_CLK, PIN_AUDIO_KIT_SD_CARD_MISO, PIN_AUDIO_KIT_SD_CARD_MOSI, PIN_AUDIO_KIT_SD_CARD_CS);

  // register supported codecs with their mime type
  multi.addDecoder(mp3, "audio/mpeg");
  multi.addDecoder(aac, "audio/aac");
  multi.addDecoder(wav, "audio/vnd.wave");

  // setup output
  auto cfg = i2s.defaultConfig(TX_MODE);
  // sd_active is setting up SPI with the right SD pins by calling 
  i2s.begin(cfg);

  // setup player
  player.setVolume(0.7);
  player.begin();

}

void loop() {
  player.copy();
}

Dependencies

You need to install the following Arduino libraries:

• Arduino AudioTools
• libhelix