#2654 NXDN Audio Removes Additive Non-Clipping Gain and uses JMBE AGC only (#2655)

Co-authored-by: denny <dennis.sheirer@gmail.com>

src/main/java/io/github/dsheirer/audio/codec/mbe/AmbeAudioModule.java

@@ -41,11 +41,11 @@ public abstract class AmbeAudioModule extends JmbeAudioModule
         {
             if(getAudioCodec() != null)
             {
-                mLog.info("AMBE CODEC successfully loaded - P25-2/DMR/NXDN audio will be available");
+                mLog.info("AMBE CODEC successfully loaded - P25-2/DMR/NXDN audio can be processed");
             }
             else
             {
-                mLog.warn("AMBE CODEC not loaded - P25-2/DMR/NXDN audio will NOT be available");
+                mLog.warn("AMBE CODEC not loaded - P25-2/DMR/NXDN audio will NOT be processed");
             }
 
             sLibraryStatusLogged = true;

src/main/java/io/github/dsheirer/dsp/gain/NonClippingGain.java

@@ -1,51 +0,0 @@
-package io.github.dsheirer.dsp.gain;
-
-public class NonClippingGain
-{
-	private float mGain;
-	private float mMaxValue;
-	
-	/**
-	 * Applies a fixed gain value to the float samples.
-	 * 
-	 * @param gain value
-	 * @param maxValue max absolute value to prevent clipping ( 0.0 to 1.0 )
-	 */
-	public NonClippingGain( float gain, float maxValue )
-	{
-		mGain = gain;
-		mMaxValue = maxValue;
-	}
-
-	/**
-	 * Applies gain to the sample
-	 */
-	public float apply( float sample )
-	{
-		float adjusted = sample * mGain;
-
-		if( adjusted > mMaxValue )
-		{
-			adjusted = mMaxValue;
-		}
-		if( adjusted < -mMaxValue )
-		{
-			adjusted = -mMaxValue;
-		}
-		
-		return adjusted;
-	}
-
-	/**
-	 * Applies gain to the sample array
-	 */
-	public float[] apply( float[] samples )
-	{
-		for( int x = 0; x < samples.length; x++ )
-		{
-			samples[ x ] = apply( samples[ x ]);
-		}
-		
-		return samples;
-	}
-}

src/main/java/io/github/dsheirer/module/decode/nxdn/audio/NXDNAudioModule.java

@@ -22,7 +22,6 @@ import io.github.dsheirer.alias.AliasList;
 import io.github.dsheirer.audio.codec.mbe.AmbeAudioModule;
 import io.github.dsheirer.audio.squelch.SquelchState;
 import io.github.dsheirer.audio.squelch.SquelchStateEvent;
-import io.github.dsheirer.dsp.gain.NonClippingGain;
 import io.github.dsheirer.message.IMessage;
 import io.github.dsheirer.module.decode.nxdn.layer3.call.Audio;
 import io.github.dsheirer.module.decode.nxdn.layer3.call.Disconnect;
@@ -41,7 +40,6 @@ import java.util.List;
 public class NXDNAudioModule extends AmbeAudioModule
 {
     private final SquelchStateListener mSquelchStateListener = new SquelchStateListener();
-    private final NonClippingGain mGain = new NonClippingGain(5.0f, 0.95f);
     private final List<Audio> mCachedAudioMessages = new ArrayList<>();
     private boolean mEncryptedCall = false;
     private boolean mEncryptedCallStateEstablished = false;
@@ -142,9 +140,7 @@ public class NXDNAudioModule extends AmbeAudioModule
         {
             for(byte[] frame : audio.getAudioFrames())
             {
-                float[] generatedAudio = getAudioCodec().getAudio(frame);
+                addAudio(getAudioCodec().getAudio(frame));
-                generatedAudio = mGain.apply(generatedAudio);
-                addAudio(generatedAudio);
             }
         }
         else

src/main/java/io/github/dsheirer/module/decode/p25/audio/P25P1AudioModule.java

@@ -22,7 +22,6 @@ import io.github.dsheirer.alias.AliasList;
 import io.github.dsheirer.audio.codec.mbe.ImbeAudioModule;
 import io.github.dsheirer.audio.squelch.SquelchState;
 import io.github.dsheirer.audio.squelch.SquelchStateEvent;
-import io.github.dsheirer.dsp.gain.NonClippingGain;
 import io.github.dsheirer.message.IMessage;
 import io.github.dsheirer.module.decode.p25.phase1.message.hdu.HDUMessage;
 import io.github.dsheirer.module.decode.p25.phase1.message.ldu.LDU1Message;