DRAFT CodecDSF

Author: pschatzmann

src/AudioTools/AudioCodecs/CodecDSF.h

@@ -57,7 +57,7 @@ struct DSFMetadata : public AudioInfo {
   float duration_sec = 0;   ///< Approximate audio duration in seconds
   uint32_t dsd_buffer_size =
       DSD_BUFFER_SIZE;  ///< Internal buffer size for DSD processing
-  float filter_q = 1.41f;
+  float filter_q = 0.5f; //1.41f;
   float filter_cutoff = 0.4f;  ///< Cutoff frequency as fraction of Nyquist
   int output_buffer_size = 1024;
 };
@@ -293,11 +293,11 @@ class DSFDecoder : public AudioDecoder {
     // parse the data
     parseFMT(data + fmtPos, len - fmtPos);
     parseData(data + dataPos, len - dataPos);
+    headerParsed = true;
 
     // update audio info and initialize filters
     setAudioInfo(meta);
 
-    headerParsed = true;
     return dataPos + sizeof(DSFDataHeader);
   }
 
@@ -397,26 +397,29 @@ class DSFDecoder : public AudioDecoder {
 
             // Add integrated value to channel accumulator
             channelAccum[ch] += channelIntegrator[ch];
+            samplesProcessed += 8;
           }
         }
       }
 
-      for (int ch = 0; ch < meta.channels; ch++) {
-        // store max_value to scale to max 1.0
-        if (channelAccum[ch] > max_value) {
-          max_value = channelAccum[ch];
-        }
+      float samplesPerChannel = samplesProcessed / meta.channels;
+
+      if (samplesPerChannel > 0) {
+        for (int ch = 0; ch < meta.channels; ch++) {
+          // Normalize by sample count and apply scaling factor
+          channelAccum[ch] = channelAccum[ch] / samplesPerChannel * 0.8f;
 
-        // Apply low-pass filter to remove high-frequency noise
-        channelAccum[ch] = channelFilters[ch].process(channelAccum[ch]);
-        // Serial.print(channelAccum[ch]/max_value);
-        // Serial.print(" ");
+          // Apply low-pass filter to remove high-frequency noise
+          channelAccum[ch] = channelFilters[ch].process(channelAccum[ch]);
+          //Serial.print(channelAccum[ch]);
+          //Serial.print(" ");
 
-        // Convert to PCM sample and store in buffer
-        writePCMSample(clip(channelAccum[ch] / max_value));
+          // Convert to PCM sample and store in buffer
+          writePCMSample(clip(channelAccum[ch]));
+        }
       }
 
-      // Serial.println();
+      //Serial.println();
 
       // Output the PCM samples for all channels
       if (pcmBuffer.isFull()) {

src/AudioTools/CoreAudio/AudioFilter/Filter.h

@@ -313,7 +313,7 @@ class LowPassFilter : public BiQuadDF2<T> {
     begin(frequency, sampleRate, q);
   }
   void begin(float frequency, float sampleRate, float q = 0.7071f) {
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     T alpha = sinW0 / ((float)q * 2.0);
     T cosW0 = cos(w0);
@@ -347,7 +347,7 @@ class HighPassFilter : public BiQuadDF2<T> {
     begin(frequency, sampleRate, q);
   }
   void begin(float frequency, float sampleRate, float q = 0.7071) {
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     T alpha = sinW0 / ((float)q * 2.0);
     T cosW0 = cos(w0);
@@ -381,7 +381,7 @@ class BandPassFilter : public BiQuadDF2<T> {
     begin(frequency, sampleRate, q);
   }
   void begin(float frequency, float sampleRate, float q = 1.0) {
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     T alpha = sinW0 / ((T)q * 2.0);
     T cosW0 = cos(w0);
@@ -416,7 +416,7 @@ class NotchFilter : public BiQuadDF2<T> {
   }
 
   void begin(float frequency, float sampleRate, float q = 1.0) {
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     T alpha = sinW0 / ((float)q * 2.0);
     T cosW0 = cos(w0);
@@ -454,7 +454,7 @@ class LowShelfFilter : public BiQuadDF2<T> {
   void begin(float frequency, float sampleRate, float gain,
              float slope = 1.0f) {
     T a = pow(10.0, gain / 40.0f);
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     // float alpha = (sinW0 * sqrt((a+1/a)*(1/slope-1)+2) ) / 2.0;
     T cosW0 = cos(w0);
@@ -496,7 +496,7 @@ class HighShelfFilter : public BiQuadDF2<T> {
   void begin(float frequency, float sampleRate, float gain,
              float slope = 1.0f) {
     T a = pow(10.0, gain / 40.0f);
-    T w0 = frequency * (2.0f * 3.141592654f / sampleRate);
+    T w0 = frequency * (2.0f * PI / sampleRate);
     T sinW0 = sin(w0);
     // float alpha = (sinW0 * sqrt((a+1/a)*(1/slope-1)+2) ) / 2.0;
     T cosW0 = cos(w0);