test-lowpass.ino

Author: pschatzmann

examples/tests/filters/test-lowpass/test-lowpass.ino

@@ -0,0 +1,49 @@
+#include "AudioTools.h"
+
+AudioInfo info(44100, 2 , 16);
+VolumeMeter meter;
+FilteredStream<int16_t, float> filtered(meter);
+SineWaveGenerator<int16_t> sine;
+GeneratedSoundStream<int16_t> sine_stream(sine);
+StreamCopy copier(filtered, sine_stream);
+float filter_freq = 8000;
+
+// Filter: or replace with other filters
+LowPassFilter<float> filter1(filter_freq, info.sample_rate);
+LowPassFilter<float> filter2(filter_freq, info.sample_rate);
+
+void setup() {
+  Serial.begin(115200);
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Warning);
+
+  sine.begin(info, 0);
+  if (!sine_stream.begin(info)){
+    Serial.println("Generator error");
+    stop();
+  }
+  
+  if (!filtered.begin(info)){
+    Serial.println("filter error");
+    stop();
+  }
+  filtered.setFilter(0, filter1);
+  filtered.setFilter(1, filter2);
+
+  if (!meter.begin(info)){
+    Serial.println("meter error");
+    stop();
+  }
+
+}
+
+void loop() {
+  for (int freq= 20; freq<20000; freq+=100){
+      meter.clear();
+      sine.setFrequency(freq);
+      copier.copyN(10);  
+      Serial.print(freq);
+      Serial.print(": ");
+      Serial.println(meter.volumeRatio());      
+  }
+  stop(); 
+}

src/AudioTools/CoreAudio/AudioStreams.h

@@ -1589,7 +1589,7 @@ class FilteredStream : public ModifyingStream {
         bool begin(AudioInfo info){
           setAudioInfo(info);
           this->channels = info.channels;
-          if (p_converter !=nullptr && info.channels!=channels){
+          if (p_converter !=nullptr  && p_converter->getChannels()!=channels){
             LOGE("Inconsistent number of channels");
             return false;
           }
@@ -1650,7 +1650,7 @@ class FilteredStream : public ModifyingStream {
         int channels=0;
         Stream *p_stream = nullptr;
         Print *p_print = nullptr;
-        ConverterNChannels<T,TF> *p_converter;
+        ConverterNChannels<T,TF> *p_converter = nullptr;
 
 };