#1241 Adds user preference to enable/disable audio normalization prior to MP3 encoding/recording. (#1242)

Co-authored-by: Dennis Sheirer <dsheirer@github.com>

src/main/java/io/github/dsheirer/audio/broadcast/BroadcastFactory.java

@@ -30,10 +30,8 @@ import io.github.dsheirer.audio.broadcast.shoutcast.v1.ShoutcastV1AudioBroadcast
 import io.github.dsheirer.audio.broadcast.shoutcast.v1.ShoutcastV1Configuration;
 import io.github.dsheirer.audio.broadcast.shoutcast.v2.ShoutcastV2AudioStreamingBroadcaster;
 import io.github.dsheirer.audio.broadcast.shoutcast.v2.ShoutcastV2Configuration;
-import io.github.dsheirer.audio.convert.IAudioConverter;
 import io.github.dsheirer.audio.convert.ISilenceGenerator;
 import io.github.dsheirer.audio.convert.InputAudioFormat;
-import io.github.dsheirer.audio.convert.MP3AudioConverter;
 import io.github.dsheirer.audio.convert.MP3Setting;
 import io.github.dsheirer.audio.convert.MP3SilenceGenerator;
 import io.github.dsheirer.preference.UserPreferences;
@@ -88,26 +86,6 @@ public class BroadcastFactory
         return null;
     }
 
-    /**
-     * Creates an audio convert to convert from 8 kHz PCM audio to the specified format
-     *
-     * @param configuration containing the requested output audio format
-     * @return audio convert or null
-     */
-    public static IAudioConverter getAudioConverter(BroadcastConfiguration configuration, InputAudioFormat inputAudioFormat,
-                                                    MP3Setting mp3Setting)
-    {
-        switch(configuration.getBroadcastFormat())
-        {
-            case MP3:
-                return new MP3AudioConverter(inputAudioFormat, mp3Setting);
-            default:
-                mLog.info("Unrecognized broadcastAudio format: " + configuration.getBroadcastFormat().name());
-        }
-
-        return null;
-    }
-
     /**
      * Creates a broadcastAudio configuration for the specified server type and format
      *

src/main/java/io/github/dsheirer/audio/convert/MP3AudioConverter.java

@@ -21,17 +21,16 @@ package io.github.dsheirer.audio.convert;
 import io.github.dsheirer.audio.AudioUtils;
 import io.github.dsheirer.dsp.filter.resample.RealResampler;
 import io.github.dsheirer.sample.ConversionUtils;
-import net.sourceforge.lame.lowlevel.LameEncoder;
-import net.sourceforge.lame.mp3.Lame;
-import org.apache.commons.math3.util.FastMath;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import net.sourceforge.lame.lowlevel.LameEncoder;
+import net.sourceforge.lame.mp3.Lame;
+import org.apache.commons.math3.util.FastMath;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Converts PCM audio packets to Mono, MP3 encoded audio
@@ -46,16 +45,20 @@ public class MP3AudioConverter implements IAudioConverter
     private byte[] mOutputFramesBuffer;
     private InputAudioFormat mInputAudioFormat;
 
+    private boolean mNormalizeAudio;
+
     /**
      * Constructs an instance.
      *
      * @param inputAudioFormat for the desired input sample rate and bit size (resampled from default 8 kHz as needed)
      * @param setting to configure the LAME encoder
+     * @param normalizeAudio to normalize the audio gain prior to encoding
      */
-    public MP3AudioConverter(InputAudioFormat inputAudioFormat, MP3Setting setting)
+    public MP3AudioConverter(InputAudioFormat inputAudioFormat, MP3Setting setting, boolean normalizeAudio)
     {
         mInputAudioFormat = inputAudioFormat;
         mEncoder = LameFactory.getLameEncoder(inputAudioFormat, setting);
+        mNormalizeAudio = normalizeAudio;
 
         //Resampling is only required if desired input sample rate is not system default of 8kHz
         if(inputAudioFormat != InputAudioFormat.SR_8000 && inputAudioFormat != InputAudioFormat.SR_32_8000)
@@ -74,7 +77,11 @@ public class MP3AudioConverter implements IAudioConverter
     public List<byte[]> convert(List<float[]> audioPackets)
     {
         List<byte[]> converted = new ArrayList<>();
-        audioPackets = AudioUtils.normalize(audioPackets);
+
+        if(mNormalizeAudio)
+        {
+            audioPackets = AudioUtils.normalize(audioPackets);
+        }
 
         if(mResampler != null)
         {

src/main/java/io/github/dsheirer/audio/convert/MP3SilenceGenerator.java

@@ -18,11 +18,10 @@
  */
 package io.github.dsheirer.audio.convert;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.util.ArrayList;
 import java.util.List;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class MP3SilenceGenerator implements ISilenceGenerator
 {
@@ -40,7 +39,7 @@ public class MP3SilenceGenerator implements ISilenceGenerator
     public MP3SilenceGenerator(InputAudioFormat inputAudioFormat, MP3Setting setting)
     {
         mInputAudioFormat = inputAudioFormat;
-        mMP3AudioConverter = new MP3AudioConverter(inputAudioFormat, setting);
+        mMP3AudioConverter = new MP3AudioConverter(inputAudioFormat, setting, false);
     }
 
     /**

src/main/java/io/github/dsheirer/gui/preference/mp3/MP3PreferenceEditor.java

@@ -25,6 +25,7 @@ import io.github.dsheirer.preference.UserPreferences;
 import io.github.dsheirer.preference.mp3.MP3Preference;
 import javafx.geometry.HPos;
 import javafx.geometry.Insets;
+import javafx.scene.control.CheckBox;
 import javafx.scene.control.ComboBox;
 import javafx.scene.control.Label;
 import javafx.scene.layout.GridPane;
@@ -44,7 +45,12 @@ public class MP3PreferenceEditor extends HBox
     private GridPane mEditorPane;
     private ComboBox<MP3Setting> mMP3SettingComboBox;
     private ComboBox<InputAudioFormat> mAudioSampleRateComboBox;
+    private CheckBox mNormalizeAudioCheckBox;
 
+    /**
+     * Constructs an instance
+     * @param userPreferences
+     */
     public MP3PreferenceEditor(UserPreferences userPreferences)
     {
         mMP3Preference = userPreferences.getMP3Preference();
@@ -65,6 +71,9 @@ public class MP3PreferenceEditor extends HBox
             Label topLabel = new Label("MP3 Encoder Preferences");
             mEditorPane.add(topLabel, 0, row++, 2, 1);
 
+
+            mEditorPane.add(getNormalizeAudioCheckBox(), 1, row++);
+
             Label label = new Label("(LAME) Encoder Setting:");
             GridPane.setHalignment(label, HPos.RIGHT);
             mEditorPane.add(label, 0, row);
@@ -76,7 +85,7 @@ public class MP3PreferenceEditor extends HBox
             mEditorPane.add(getAudioSampleRateComboBox(), 1, row++);
 
             Label notice = new Label("Note: sdrtrunk default 8 kHz audio rate is resampled to input sample rate before MP3 encoding");
-            mEditorPane.add(notice, 0, row, 2, 1);
+            mEditorPane.add(notice, 0, row++, 2, 1);
         }
 
         return mEditorPane;
@@ -109,4 +118,17 @@ public class MP3PreferenceEditor extends HBox
 
         return mAudioSampleRateComboBox;
     }
+
+    private CheckBox getNormalizeAudioCheckBox()
+    {
+        if(mNormalizeAudioCheckBox == null)
+        {
+            mNormalizeAudioCheckBox = new CheckBox("Normalize Audio Before Encoding");
+            mNormalizeAudioCheckBox.setSelected(mMP3Preference.isNormalizeAudioBeforeEncode());
+            mNormalizeAudioCheckBox.onActionProperty().set(event ->
+                    mMP3Preference.setNormalizeAudioBeforeEncode(getNormalizeAudioCheckBox().isSelected()));
+        }
+
+        return mNormalizeAudioCheckBox;
+    }
 }

src/main/java/io/github/dsheirer/preference/mp3/MP3Preference.java

@@ -24,11 +24,10 @@ import io.github.dsheirer.audio.convert.MP3Setting;
 import io.github.dsheirer.preference.Preference;
 import io.github.dsheirer.preference.PreferenceType;
 import io.github.dsheirer.sample.Listener;
+import java.util.prefs.Preferences;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.prefs.Preferences;
-
 /**
  * User preferences for playlists
  */
@@ -36,11 +35,14 @@ public class MP3Preference extends Preference
 {
     private static final String PREFERENCE_KEY_AUDIO_MP3_SETTING = "audio.mp3.setting";
     private static final String PREFERENCE_KEY_AUDIO_MP3_SAMPLE_RATE = "audio.mp3.sample.rate";
+    private static final String PREFERENCE_KEY_AUDIO_MP3_NORMALIZE_BEFORE_ENCODE = "audio.mp3.normalize.before.encode";
     private final static Logger mLog = LoggerFactory.getLogger(MP3Preference.class);
     private Preferences mPreferences = Preferences.userNodeForPackage(MP3Preference.class);
     private InputAudioFormat mInputAudioFormat;
     private MP3Setting mMP3Setting;
 
+    private Boolean mNormalizeAudio;
+
     /**
      * Constructs this preference with an update listener
      * @param updateListener to receive notifications whenever these preferences change
@@ -128,4 +130,29 @@ public class MP3Preference extends Preference
         mPreferences.put(PREFERENCE_KEY_AUDIO_MP3_SAMPLE_RATE, mInputAudioFormat.name());
         notifyPreferenceUpdated();
     }
+
+    /**
+     * Indicates if the user prefers to normalize audio before encoding to MP3
+     * @return true to normalize
+     */
+    public boolean isNormalizeAudioBeforeEncode()
+    {
+        if(mNormalizeAudio == null)
+        {
+            mNormalizeAudio = mPreferences.getBoolean(PREFERENCE_KEY_AUDIO_MP3_NORMALIZE_BEFORE_ENCODE, false);
+        }
+
+        return mNormalizeAudio;
+    }
+
+    /**
+     * Sets the preferenced to normalize audio before encoding to MP3.
+     * @param normalizeAudio true to normalize
+     */
+    public void setNormalizeAudioBeforeEncode(boolean normalizeAudio)
+    {
+        mNormalizeAudio = normalizeAudio;
+        mPreferences.putBoolean(PREFERENCE_KEY_AUDIO_MP3_NORMALIZE_BEFORE_ENCODE, normalizeAudio);
+        notifyPreferenceUpdated();
+    }
 }

src/main/java/io/github/dsheirer/record/AudioSegmentRecorder.java

@@ -29,9 +29,6 @@ import io.github.dsheirer.record.wave.AudioMetadata;
 import io.github.dsheirer.record.wave.AudioMetadataUtils;
 import io.github.dsheirer.record.wave.WaveWriter;
 import io.github.dsheirer.sample.ConversionUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -39,6 +36,8 @@ import java.nio.ByteBuffer;
 import java.nio.file.Path;
 import java.util.List;
 import java.util.Map;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Recording utility for audio segments
@@ -96,7 +95,9 @@ public class AudioSegmentRecorder
             InputAudioFormat inputAudioFormat = userPreferences.getMP3Preference().getAudioSampleRate();
             MP3Setting mp3Setting = userPreferences.getMP3Preference().getMP3Setting();
 
-            MP3AudioConverter converter = new MP3AudioConverter(inputAudioFormat, mp3Setting);
+            boolean normalizeAudio = userPreferences.getMP3Preference().isNormalizeAudioBeforeEncode();
+
+            MP3AudioConverter converter = new MP3AudioConverter(inputAudioFormat, mp3Setting, normalizeAudio);
             List<byte[]> mp3Frames = converter.convert(audioSegment.getAudioBuffers());
             for(byte[] mp3Frame: mp3Frames)
             {