FFT remove shiftValues

Author: pschatzmann

examples/examples-audiokit/streams-audiokit-fft-frequp/streams-audiokit-fft-frequp.ino renamed to examples/sandbox/streams-audiokit-fft-frequp/streams-audiokit-fft-frequp.ino

@@ -0,0 +1,85 @@
+/**
+ * @file streams-url_fft_up-audiokit.ino
+ * @author Phil Schatzmann
+ * @brief Using FFT to shift frequency up quite a bit
+ * @version 0.1
+ * @date 2022-06-28
+ * 
+ * @copyright Copyright (c) 2022
+ * 
+ */
+
+#include "AudioTools.h"
+#include "AudioLibs/AudioKit.h"
+#include "AudioCodecs/CodecMP3Helix.h"
+#include "AudioLibs/AudioRealFFT.h" // or AudioKissFFT
+
+URLStream url("SSID","PWD");
+AudioKitStream kit;  
+AudioRealFFT fft; 
+ChannelFormatConverterStream cf(fft);
+EncodedAudioStream dec(&cf, new MP3DecoderHelix()); // Decoding stream
+StreamCopy copier(dec, cf);  // copy mic to tfl
+int channels = 2;
+int samples_per_second = 44100;
+int bits_per_sample = 16;
+float value=0;
+
+// process fft result
+void fftResult(AudioFFTBase &bfft){
+  // get result components
+  float* real = fft.realArray();
+  float* img = fft.imgArray();
+  // increase frequencies by n bins
+  int n = 0;
+  //fft.shiftValues(real, n);
+  //fft.shiftValues(img, n);
+  // invert fft with updated values
+  float *result = fft.ifft(real, img);
+
+  // output audio
+  int16_t samples[2];
+  for (int j=0;j<fft.length();j++){
+    //Serial.println(result[j]);
+    samples[0] = result[j]; // channel 0
+    samples[1] = result[j]; // channel 1
+    kit.write((uint8_t*)&samples, sizeof(samples));
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+  AudioLogger::instance().begin(Serial, AudioLogger::Info);
+
+  // setup Audiokit
+  auto cfg = kit.defaultConfig(TX_MODE);
+  cfg.channels = channels;
+  cfg.sample_rate = samples_per_second;
+  cfg.bits_per_sample = bits_per_sample;
+  kit.begin(cfg);
+  kit.setVolume(1.0);
+
+  // Setup FFT
+  auto tcfg = fft.defaultConfig();
+  tcfg.length = 1024;
+  tcfg.channels = channels;
+  tcfg.sample_rate = samples_per_second;
+  tcfg.bits_per_sample = bits_per_sample;
+  tcfg.callback = &fftResult;
+  fft.begin(tcfg);
+
+  copier.setCheckAvailableForWrite(false);
+  // mp3 radio
+  url.begin("https://stream.live.vc.bbcmedia.co.uk/bbc_world_service","audio/mp3");
+
+  // convert 2 to 1 channel
+  cf.begin(2,1);
+
+  // initialize decoder
+  dec.begin();
+
+}
+
+void loop() { 
+  copier.copy();
+}

examples/sandbox/streams-url-fft_up-audiokit/streams-url_fft_up-audiokit.ino

@@ -26,7 +26,7 @@ struct AudioFFTResult {
     }
 };
 
-/// Configuration for AudioFFT
+/// Configuration for AudioFFT. If there are more then 1 channel the channel_used is defining which channel is used to perform the fft on.
 struct AudioFFTConfig : public  AudioBaseInfo {
     AudioFFTConfig(){
         channels = 2;
@@ -59,7 +59,7 @@ class FFTDriver {
 };
 
 /**
- * @brief Executes FFT using audio data. The Driver which is passed in the constructor selects a specifc FFT implementation
+ * @brief Executes FFT using audio data. The Driver which is passed in the constructor selects a specifc FFT implementation. 
  * @author Phil Schatzmann
  * @copyright GPLv3
  */

src/AudioLibs/AudioFFT.h

@@ -68,36 +68,11 @@ class AudioRealFFT : public AudioFFTBase {
         float* ifft(float *real, float* complex){
            // update mirrored values
            int len = length();
-           for (int j=0;j<size();j++){
-               real[len-j] = real[j]; 
-               complex[len-j] = complex[j]; 
-           }
            static_cast<FFTDriverRealFFT*>(driver())->p_fft_object->do_ifft(real, complex);
            return real;
         }
 
-        /// Shift the values in the array up or down
-        void shiftValues(float *values, int n){
-            if (n>0){
-                // shift values up
-                for (int j=n;j<size();j++){
-                    values[j]=values[j-n];
-                }
-                // clear beginning
-                for (int j=0;j<n;j++){
-                    values[j]=0;
-                }   
-            } else {
-                // shift values down
-                for (int j=size();j>=0;j--){
-                    values[j+n]=values[j];
-                }
-                // clear end
-                for (int j=0;j<abs(n);j++){
-                    values[size()-j]=0;
-                }   
-            }
-        }
+
 
         FFTDriverRealFFT* driverEx() {
             return (FFTDriverRealFFT*)driver();

src/AudioLibs/AudioRealFFT.h

@@ -33,7 +33,7 @@ class ChannelFormatConverterStreamT : public AudioStreamX {
 
         virtual size_t write(const uint8_t *data, size_t size) override { 
            if (from_channels==to_channels){
-              return p_stream->write(data, size);
+              return p_print->write(data, size);
            }
            size_t resultBytes = convert(data, size);
            assert(resultBytes = factor*size);