P25 Audio Decoder - changed sync pattern matcher to allow up to 2 bit mismatches on audio message frames when in the middle of a call.

Encrypted audio is still going to the audio output -- have to add error detection and correction to the ldu link control messages before I can use the encryption flag as a valid sentinel value.

src/bits/SyncPatternMatcher.java

@@ -23,7 +23,7 @@ package bits;
  * 
  * Note: works for sync patterns up to 63 bits (integer size - 1 ) long.  
  * If a 64 bit or larger sync pattern is applied, then the wrapping feature
- * of the Integer.rotate methods will wrap the MSB around to the LSB and
+ * of the Long.rotate methods will wrap the MSB around to the LSB and
  * corrupt the matching value.
  *
  */
@@ -32,6 +32,8 @@ public class SyncPatternMatcher
 	private long mBits = 0;
 	private long mMask = 0;
 	private long mSync = 0;
+	private boolean mSoftMode = false;
+	private int mSoftModeErrorThreshold = 0;
 	
 	public SyncPatternMatcher( boolean[] syncPattern )
 	{
@@ -54,6 +56,21 @@ public class SyncPatternMatcher
 		mMask = getMask( sync );
 	}
 
+	/**
+	 * Constructs the sync pattern matcher and defines the soft mode maximum
+	 * number of bit errors to allow in the pattern match.
+	 * 
+	 * @param sync pattern
+	 * @param softModeErrorThreshold - maximum bit errors (ie pattern mismatch
+	 * positions) when considering a sync match
+	 */
+	public SyncPatternMatcher( long sync, int softModeErrorThreshold )
+	{
+		this( sync );
+		
+		mSoftModeErrorThreshold = softModeErrorThreshold;
+	}
+
 	/**
 	 * Generates an all ones mask corresponding to the sync pattern
 	 */
@@ -91,6 +108,25 @@ public class SyncPatternMatcher
 	 */
 	public boolean matches()
 	{
-		return ( mBits == mSync );
+		if( mSoftMode )
+		{
+			long difference = mBits ^ mSync;
+			
+			return difference == 0 || 
+					Long.bitCount( difference ) <= mSoftModeErrorThreshold;
+		}
+		else
+		{
+			return ( mBits == mSync );
+		}
+	}
+
+	/**
+	 * Sets the sync pattern matcher in soft mode which allows up to the soft
+	 * mode threshold number of bit errors when considering a sync pattern match
+	 */
+	public void setSoftMode( boolean softMode )
+	{
+		mSoftMode = softMode;
 	}
 }

src/decode/p25/P25Decoder.java

@@ -88,7 +88,7 @@ public class P25Decoder extends Decoder
 	
 	/* Message framers and handlers */
 	private P25MessageFramer mNormalFramer;
-	private P25MessageFramer mInvertedFramer;
+//	private P25MessageFramer mInvertedFramer;
 	private P25MessageProcessor mMessageProcessor;
 	
 	/* Audio */
@@ -114,9 +114,9 @@ public class P25Decoder extends Decoder
                 FrameSync.P25_PHASE1.getSync(), 64, false, mAliasList );
         mNormalFramer.setListener( mMessageProcessor );
 
-        mInvertedFramer = new P25MessageFramer( 
-                FrameSync.P25_PHASE1_INVERTED.getSync(), 64, true, mAliasList );
-        mInvertedFramer.setListener( mMessageProcessor );
+//        mInvertedFramer = new P25MessageFramer( 
+//                FrameSync.P25_PHASE1_INVERTED.getSync(), 64, true, mAliasList );
+//        mInvertedFramer.setListener( mMessageProcessor );
 
         /* Setup demodulation chains based on sample type (real or complex) and 
          * modulation (C4FM or CQPSK) */
@@ -139,7 +139,7 @@ public class P25Decoder extends Decoder
 				mCQPSKDemodulator.setListener( mCQPSKSlicer );
 				
 				mCQPSKSlicer.addListener( mNormalFramer );
-				mCQPSKSlicer.addListener( mInvertedFramer );
+//				mCQPSKSlicer.addListener( mInvertedFramer );
 			}
 			else /* C4FM */
 			{
@@ -172,7 +172,7 @@ public class P25Decoder extends Decoder
 			mSymbolFilter.setListener( mC4FMSlicer );
 			
 	        mC4FMSlicer.addListener( mNormalFramer );
-	        mC4FMSlicer.addListener( mInvertedFramer );
+//	        mC4FMSlicer.addListener( mInvertedFramer );
 		}
 		
 		mAudioOutput = new P25AudioOutput( resourceManager );

src/decode/p25/P25MessageFramer.java

@@ -34,6 +34,8 @@ import edac.CRCP25;
 
 public class P25MessageFramer implements Listener<Dibit>
 {
+	private static final int SYNC_PATTERN_MISMATCH_THRESHOLD = 2;
+	
 	private final static Logger mLog = 
 							LoggerFactory.getLogger( P25MessageFramer.class );
 	
@@ -80,7 +82,7 @@ public class P25MessageFramer implements Listener<Dibit>
 	                         boolean inverted,
 	                         AliasList aliasList )
 	{
-		mMatcher = new SyncPatternMatcher( sync );
+		mMatcher = new SyncPatternMatcher( sync, SYNC_PATTERN_MISMATCH_THRESHOLD );
 		mInverted = inverted;
 		mAliasList = aliasList;
 
@@ -256,10 +258,12 @@ public class P25MessageFramer implements Listener<Dibit>
 					break;
 				case HDU:
 					mComplete = true;
+					mMatcher.setSoftMode( true );
                     dispatch( new HDUMessage( mMessage.copy(), mDUID, mAliasList ) );
 					break;
 				case LDU1:
 					mComplete = true;
+					mMatcher.setSoftMode( true );
 					
 					LDU1Message ldu1 = new LDU1Message( mMessage.copy(), 
 							mDUID, mAliasList );
@@ -269,9 +273,12 @@ public class P25MessageFramer implements Listener<Dibit>
 					break;
 				case LDU2:
 					mComplete = true;
+					mMatcher.setSoftMode( true );
                     dispatch( new LDU2Message( mMessage.copy(), mDUID, mAliasList ) );
 					break;
 				case PDU0:
+					mMatcher.setSoftMode( false );
+
 					/* Remove interleaving */
 					P25Interleave.deinterleaveData( mMessage, PDU0_BEGIN, PDU0_END );
 	
@@ -390,6 +397,8 @@ public class P25MessageFramer implements Listener<Dibit>
 					mComplete = true;
 					break;
 				case PDUC:
+					mMatcher.setSoftMode( true );
+
 					/* De-interleave the latest block*/
 					P25Interleave.deinterleaveData( mMessage, 
 							mMessage.size() - 196, mMessage.size() );
@@ -438,10 +447,12 @@ public class P25MessageFramer implements Listener<Dibit>
 					}
 					break;
 				case TDU:
+					mMatcher.setSoftMode( true );
                     dispatch( new TDUMessage( mMessage.copy(), mDUID, mAliasList ) );
 					mComplete = true;
 					break;
 				case TDULC:
+					mMatcher.setSoftMode( true );
 					TDULinkControlMessage tdulc =  new TDULinkControlMessage( 
 							mMessage.copy(), mDUID, mAliasList );
 
@@ -452,6 +463,7 @@ public class P25MessageFramer implements Listener<Dibit>
 					mComplete = true;
 					break;
 				case TSBK1:
+					mMatcher.setSoftMode( true );
 					/* Remove interleaving */
 					P25Interleave.deinterleaveData( mMessage, TSBK_BEGIN, TSBK_END );
 	

src/decode/p25/audio/P25AudioOutput.java

@@ -7,6 +7,9 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
 import javax.sound.sampled.AudioInputStream;
 import javax.sound.sampled.AudioSystem;
+import javax.sound.sampled.Control;
+import javax.sound.sampled.FloatControl;
+import javax.sound.sampled.FloatControl.Type;
 import javax.sound.sampled.LineUnavailableException;
 import javax.sound.sampled.SourceDataLine;
 
@@ -20,7 +23,6 @@ import audio.AudioType;
 import audio.IAudioOutput;
 import audio.IAudioTypeListener;
 import audio.SquelchListener;
-import audio.SquelchListener.SquelchState;
 import controller.ResourceManager;
 import controller.ThreadPoolManager;
 import controller.ThreadPoolManager.ThreadType;
@@ -145,6 +147,17 @@ public class P25AudioOutput implements IAudioOutput, IAudioTypeListener,
 				        	/* Open the audio line with room for two buffers */ 
 				        	mOutput.open( IMBEAudioFormat.PCM_SIGNED_8KHZ_16BITS, 
 				        			PROCESSED_AUDIO_FRAME_SIZE * 2 );
+				        	
+				        	Control[] controls = mOutput.getControls();
+
+				        	FloatControl gain = (FloatControl)mOutput
+				        			.getControl( FloatControl.Type.MASTER_GAIN );
+
+				        	if( gain != null )
+				        	{
+//				        		gain.setValue( 4.0f );
+				        	}
+				        	
 							mCanProcessAudio = true;
 			        	}
 				        else

src/decode/p25/message/ldu/LDU2Message.java

@@ -44,19 +44,24 @@ public class LDU2Message extends LDUMessage
     {
 		StringBuilder sb = new StringBuilder();
 		
-		sb.append( super.getMessageStub() );
 		
 		Encryption encryption = getEncryption();
 		
 		if( encryption != Encryption.UNENCRYPTED )
 		{
-			sb.append( "ENCRYPTION:" );
+			sb.append( "NAC:" );
+			sb.append( getNAC() );
+			sb.append( " " );
+			sb.append( getDUID().getLabel() );
+			
+			sb.append( " ENCRYPTED VOICE:" );
 			sb.append( encryption.name() );
 			sb.append( " KEY ID:" + getKeyID() );
 			sb.append( " MSG INDICATOR:" + getMessageIndicator() );
 		}
 		else
 		{
+			sb.append( super.getMessageStub() );
 			sb.append( "UNENCRYPTED" );
 		}