feat ✨: Updated src/main.cpp to utilize FormatConverterStream for converting 32-bit I2S input to 16-bit output and configured an AudioFFTBase with the correct bits per sample

- Modified `src/main.cpp` to use `FormatConverterStream` for converting 32-bit I2S input to 16-bit output, then configured an `AudioFFTBase` with the appropriate bits per sample.

src/main.cpp

@@ -3,12 +3,17 @@
 #include "AudioTools/AudioLibs/AudioRealFFT.h" // or AudioKissFFT
 
 I2SStream i2sStream;              // I2S input stream for INMP441
-AudioRealFFT fft;                // FFT analyzer
-StreamCopy copier(fft, i2sStream);  // copy I2S mic to FFT
+AudioRealFFT fft;                 // FFT analyzer
+FormatConverterStream converter(i2sStream); // Convert 32-bit input to 16-bit output
+StreamCopy copier(fft, converter);  // copy converted data to FFT
 
 int channels = 1;                // INMP441 is mono
 int samples_per_second = 11025;
-int bits_per_sample = 32;        // INMP441 sends 24-bit data in 32-bit words
+int input_bits_per_sample = 32;        // INMP441 sends 24-bit data in 32-bit words
+int fft_bits_per_sample = 16;
+
+AudioInfo from(samples_per_second, channels, input_bits_per_sample);                                           
+AudioInfo to(samples_per_second, channels, fft_bits_per_sample);  
 
 const char* solfegeName(uint8_t midiNote) {
     static const char* solfegeNames[] = {
@@ -30,7 +35,7 @@ void fftResult(AudioFFTBase &fft) {
         const char* solfege = solfegeName(midiNote);
         int octave = (midiNote / 12) - 1;
 
-        Serial.print(freq, 2);
+        Serial.print(freq, 0);
         Serial.print(" Hz | ");
 
         Serial.print("MIDI ");
@@ -50,6 +55,9 @@ void fftResult(AudioFFTBase &fft) {
 
         Serial.print(" | Diff: ");
         Serial.println(diff, 2);
+
+        Serial.print(" | Amp: ");
+        Serial.println(result.magnitude, 0);
     }
 }
 
@@ -61,7 +69,7 @@ void setup() {
   // Configure I2SStream for INMP441
   auto cfg = i2sStream.defaultConfig(RX_MODE);
   cfg.i2s_format = I2S_STD_FORMAT;
-  cfg.bits_per_sample = bits_per_sample;
+  cfg.bits_per_sample = input_bits_per_sample;
   cfg.channels = channels;
   cfg.sample_rate = samples_per_second;
   cfg.is_master = true;
@@ -70,12 +78,15 @@ void setup() {
   cfg.pin_data = 10;   // SD
   i2sStream.begin(cfg);
 
+  // Configure FormatConverterStream to convert 32-bit to 16-bit
+  converter.begin(from, to);  // Convert to 16-bit
+
   // Configure FFT
   auto tcfg = fft.defaultConfig();
   tcfg.length = 8192;    // 186ms @ 11kHz minimun C2 theoretical
   tcfg.channels = channels;
   tcfg.sample_rate = samples_per_second;
-  tcfg.bits_per_sample = bits_per_sample;
+  tcfg.bits_per_sample = fft_bits_per_sample; // FFT expects 16-bit data after conversion
   tcfg.callback = &fftResult;
   fft.begin(tcfg);