is_auto_center_read for AnalogAudioStream/ESP32

Author: pschatzmann

examples/examples-stream/streams-adc-i2s/streams-adc-i2s.ino

@@ -13,7 +13,7 @@ AudioInfo info(44100, 2, 16);
 AnalogAudioStream in; 
 I2SStream out;                        
 StreamCopy copier(out, in); // copy in to out
-ConverterAutoCenter<int16_t> converter;
+ConverterAutoCenterT<int16_t> converter;
 
 // Arduino Setup
 void setup(void) {

src/AudioAnalog/AnalogAudioArduino.h

@@ -56,13 +56,13 @@ class AnalogDriverArduino : public AnalogDriverBase {
     return buffer->readArray(values, bytes);
   }
 
-  int availableForWrite() {
+  int availableForWrite() override {
     if (config.rx_tx_mode == RX_MODE) return 0;
     if (buffer == nullptr) return 0;
     return config.is_blocking_write ? config.buffer_size : buffer->availableForWrite();
   }
 
-  size_t write(const uint8_t *data, size_t len) {
+  size_t write(const uint8_t *data, size_t len) ovrride {
     LOGD("write: %d", (int)len);
     if (config.rx_tx_mode == RX_MODE) return 0;
     // only process full frames

src/AudioAnalog/AnalogAudioBase.h

@@ -151,12 +151,13 @@ class AnalogConfig : public AudioInfo {
 
 class AnalogDriverBase {
 public:
-    virtual bool begin(AnalogConfig cfg);
-    virtual void end();
+    virtual bool begin(AnalogConfig cfg) = 0;
+    virtual void end() = 0;
 //  virtual void setMaxSampleRate() {}
     virtual size_t write(const uint8_t *src, size_t size_bytes) { return 0;}
-    virtual size_t readBytes(uint8_t *dest, size_t size_bytes);
-    virtual int available();
+    virtual size_t readBytes(uint8_t *dest, size_t size_bytes) = 0;
+    virtual int available() = 0;
+    virtual int availableForWrite() { return DEFAULT_BUFFER_SIZE; }
 };
 
 } // ns

src/AudioAnalog/AnalogAudioESP32.h

@@ -48,6 +48,11 @@ class AnalogDriverESP32  : public AnalogDriverBase {
       TRACEI();
       cfg.logInfo();
 
+      if (adc_config.is_auto_center_read){
+        LOGI("auto_center")
+        auto_center.begin(cfg.channels, cfg.bits_per_sample);
+      }
+
       if (!is_driver_installed){
         port_no = (i2s_port_t) cfg.port_no;
 
@@ -182,6 +187,10 @@ class AnalogDriverESP32  : public AnalogDriverBase {
       if (i2s_read(port_no, dest, size_bytes, &result, portMAX_DELAY)!=ESP_OK){
         TRACEE();
       }
+      // make sure that the center is at 0
+      if (adc_config.is_auto_center_read){
+        auto_center.convert(dest, result);
+      }
       LOGD( "%s - len: %d -> %d", __func__, size_bytes, result);
       return result;
     }
@@ -192,6 +201,7 @@ class AnalogDriverESP32  : public AnalogDriverBase {
 
   protected:
     AnalogConfig adc_config;
+    ConverterAutoCenter auto_center;
     i2s_port_t port_no;
     bool active = false;
     bool is_driver_installed = false;

src/AudioAnalog/AnalogAudioMBED.h

@@ -37,6 +37,7 @@ class AnalogDriverMBED : public AnalogDriverBase {
       return false;
     }
     info = cfg;
+    auto_center.begin(config.channels, config.bits_per.sample);
     int n_samples = cfg.buffer_size / (cfg.bits_per_sample / 8);
     ring_buffer.resize(n_samples);
     switch (info.channels) {
@@ -114,6 +115,12 @@ class AnalogDriverMBED : public AnalogDriverBase {
       }
       break;
     }
+
+    // make sure that the center is at 0
+    if (adc_config.is_auto_center_read){
+        auto_center.convert(dest, result);
+    }
+
     return result;
   }
 
@@ -122,6 +129,7 @@ class AnalogDriverMBED : public AnalogDriverBase {
 protected:
   audio_tools::RingBuffer<Sample> ring_buffer{0};
   AnalogConfig info;
+  ConverterAutoCenter auto_center;
   AdvancedDAC dac1{PIN_DAC_1};
   AdvancedDAC dac2{PIN_DAC_2};
   AdvancedADC adc1{PIN_ANALOG_START};

src/AudioConfig.h

@@ -679,6 +679,10 @@ typedef WiFiClient WiFiClientSecure;
 #  define INLINE_VAR static 
 #endif
 
+#ifndef ANALOG_MAX_SAMPLE_RATE
+#  define ANALOG_MAX_SAMPLE_RATE 44000
+#endif
+
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wunused-function"
 #pragma GCC diagnostic ignored "-Wvla"

src/AudioTools/BaseConverter.h

@@ -111,16 +111,17 @@ class ConverterScaler : public  BaseConverter {
  * @tparam T 
  */
 template<typename T>
-class ConverterAutoCenter : public  BaseConverter {
+class ConverterAutoCenterT : public  BaseConverter {
     public:
-        ConverterAutoCenter(int channels=2){
+        ConverterAutoCenterT(int channels=2){
             this->channels = channels;
         }
 
         size_t convert(uint8_t(*src), size_t byte_count) {
             int size = byte_count / channels / sizeof(T);
             T *sample = (T*) src;
             setup((T*)src, size);
+            // convert data
             if (is_setup){
                 for (size_t j=0; j<size; j++){
                     for (int i=0;i<channels;i++){
@@ -133,33 +134,94 @@ class ConverterAutoCenter : public  BaseConverter {
         }
 
     protected:
-        T offset;
-        float left;
-        float right;
+        T offset = 0;
+        float left = 0.0;
+        float right = 0.0;
         bool is_setup = false;
         int channels;
 
         void setup(T *src, size_t size){
+            if (size==0) return;
             if (!is_setup) {
-                T *sample = (T*) src;
-                for (size_t j=0;j<size;j++){
-                    left += *sample++;
-                    right += *sample++;
-                }
-                left = left / size;
-                right = right / size;
-
-                if (left>0){
-                    offset = left;
-                    is_setup = true;
-                } else if (right>0){
-                    offset = right;
+                if (channels==1){
+                    T *sample = (T*) src;
+                    for (size_t j=0;j<size;j++){
+                        left += *sample++;
+                    }
+                    offset = left / size;
                     is_setup = true;
+                    LOGD("offset: %d",offset);
+                } else if (channels==2){
+                    T *sample = (T*) src;
+                    for (size_t j=0;j<size;j++){
+                        left += *sample++;
+                        right += *sample++;
+                    }
+                    left = left / size;
+                    right = right / size;
+
+                    if (left>0){
+                        offset = left;
+                        is_setup = true;
+                    } else if (right>0){
+                        offset = right;
+                        is_setup = true;
+                    }
+                    LOGD("offset: %d",offset);
                 }
             }
         }
 };
 
+/**
+ * @brief Makes sure that the avg of the signal is set to 0
+ * @ingroup convert
+ */
+class ConverterAutoCenter : public  BaseConverter {
+  public:
+    ConverterAutoCenter() = default;
+
+    ConverterAutoCenter(int channels, int bitsPerSample){
+        begin(channels, bitsPerSample);
+    }
+    ~ConverterAutoCenter(){
+        if (p_converter!=nullptr) delete p_converter;
+    }
+
+    void begin(int channels, int bitsPerSample){
+        this->channels = channels;
+        this->bits_per_sample = bitsPerSample;
+        if (p_converter!=nullptr) delete p_converter;
+        switch(bits_per_sample){
+            case 16:{
+                p_converter = new ConverterAutoCenterT<int16_t>(channels);
+                break;
+            }
+            case 24:{
+                p_converter = new ConverterAutoCenterT<int24_t>(channels);
+                break;
+            }
+            case 32:{
+                p_converter = new ConverterAutoCenterT<int32_t>(channels);
+                break;
+            }
+        }
+    }
+
+    size_t convert(uint8_t *src, size_t size) override {
+        if(p_converter==nullptr) return 0;
+        return p_converter->convert(src, size);
+    }
+
+
+  protected:
+    int channels;
+    int bits_per_sample;
+    BaseConverter *p_converter = nullptr;
+};
+
+
+
 /**
  * @brief Switches the left and right channel
  * @ingroup convert