Writing i2s Stream to WAV File won't work

[hdsjulian]

I'm trying to write my i2sStream onto a file so that i can see what the mic's input is (for debugging reasons mainly).
i2sStream itself works fine. Taking a generated white noise and writing it into a file works too (that section is commented out in the following code). However writing the i2sStream into the file somehow fails.
what might I be doing wrong?

#include <Arduino.h>
#include <AudioTools.h>
#include "AudioTools/AudioLibs/AudioESP32FFT.h"
#include "SD.h"
#include "SPI.h"

// I2S pins
#define I2S_BCK_PIN 15   // Bit Clock (BCK)
#define I2S_LRCK_PIN 17  // Left-Right Clock (LRCK)
#define I2S_DATA_PIN 16  // Data (DOUT)
#define CHANNELS 1
#define IN_SAMPLES_PER_SECOND 48000
#define IN_BITS_PER_SAMPLE 16


#define SD_MISO 13
#define SD_MOSI 11
#define SD_CLK  12
#define SD_CS   10


#define OUT_SAMPLES_PER_SECOND 48000
#define OUT_BITS_PER_SAMPLE 16

I2SStream i2sStream;
AudioInfo info(48000, 1, 16);
//AudioInfo to(48000, 1, 16);
//WhiteNoiseGenerator<int16_t> noise(32000);                             // subclass of SoundGenerator with max amplitude of 32000
//GeneratedSoundStream<int16_t> in_stream(noise);  

File audioFile;                                                   // final output stream
WAVEncoder encoder;
EncodedAudioStream out_stream(&audioFile, &encoder);  


StreamCopy copier(out_stream, i2sStream);
SPIClass spi = SPIClass(SPI2_HOST);
unsigned long lastMillis = 0;
int fileCounter = 0;

void setup() {
  Serial.begin(115200); // Initialize Serial for Serial Plotter
  while (!Serial) {
    delay(10); // Wait for Serial to be ready
  }
  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Warning);

  // Configure I2S using AudioTools
  
  auto cfg = i2sStream.defaultConfig(RX_MODE);
  cfg.bits_per_sample = IN_BITS_PER_SAMPLE; // 16-bit samples
  cfg.channels = CHANNELS;         // Mono
  cfg.sample_rate = IN_SAMPLES_PER_SECOND;  // Sample rate
  cfg.is_master = false;    // Slave mode
  cfg.i2s_format = I2S_STD_FORMAT;
  cfg.use_apll = true;
  cfg.pin_bck = I2S_BCK_PIN;
  cfg.pin_ws = I2S_LRCK_PIN;
  cfg.pin_data_rx = I2S_DATA_PIN;
  i2sStream.begin(cfg); // Start I2S
  
    lastMillis = millis(); // Initialize startMillis for timing
  
//auto cnfg = noise.defaultConfig();
  //cnfg.copyFrom(info);
  //noise.begin(info);
  //in_stream.begin(cnfg); // Start the input stream with noise generator

  spi.begin(SD_CLK, SD_MISO, SD_MOSI, SD_CS); // Initialize SPI for SD card
  if (!SD.begin(SD_CS, spi, 8000000)) { // Initialize SD card with SPI
    Serial.println("SD card initialization failed!");
    while (true); // Halt execution if SD card fails to initialize
  }
  uint8_t cardType = SD.cardType();
  SD.remove("/audio.wav");
  audioFile = SD.open("/audio.wav", FILE_WRITE);
  if (!audioFile) {
    Serial.println("Failed to open file on SD card!");
    while (true); // Halt execution if file fails to open
  }
  Serial.println("File opened on SD card.");
  
  out_stream.begin(info);


}



void loop() {
    if (millis() - lastMillis >= 30000) { // Check every 30 seconds
        audioFile.close();
        fileCounter++;
        audioFile = SD.open("/audio" + String(fileCounter) + ".wav", FILE_WRITE);
        lastMillis = millis(); // Reset the timer
        Serial.println("File closed and new file opened: audio" + String(fileCounter) + ".wav");
    }
  copier.copy(); 
  }

[pschatzmann]

Please read the Encoding Wiki documentation !

[hdsjulian]

I did, yet either i misunderstood or missed something. Would you care to point me to what i'm missing?

[pschatzmann]

Mainly the second note in the Encoding Section! You create a new file but you do not reopen the encoder!

So you will get just a new file with PCM data but w/o WAV header...

[hdsjulian]

Ah. i should have specified. My WAV files are 72 kb long after 30 seconds and just contain emptiness / white noise. The reopening of the encoder part has been fixed, still no result.

[pschatzmann]

• Check that the micophone provides valid audio
• Check that the write speed can keep up with the amount of generated data.