Initial commit of redesigned internal processing and audio management.

Note: Several of the decoders are currently non-functioning in this
commit.  If you want the latest functioning codebase, please checkout
the commit prior to this one.  All decoders will eventually be updated
with this new architecture.

Currently broken:
- Logging and recording
- Aux decoders (Fleetsync/MDC/LoJack/Tait)
- LTR/Passport decoders

Changes in this commit:
- Module architecture for decoders and components with central
provisioning by the DecoderFactory
- Transition from Complex sample stream processing to float buffer
processing for improved memory management
- Redesigned filter structures - to support buffers and streams
- Resolved several memory leak issues
- Universal sharing of the thread pool manager
- Added centralized audio management with call/user prioritization and
new gui with mute/volume controls
- Embedded audio metadata for eventual streaming support
- Redesigned ProcessingChain to support independent re-use
- Added new TrafficChannelManager to handle traffic channel allocations
- Traffic Channel pool size and Call timeout available in P25 and
MPT1327 configs
- Redesigned channel and decoder gui components

src/audio/AudioModule.java

@@ -0,0 +1,191 @@
+package audio;
+
+import module.Module;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import sample.Listener;
+import sample.real.IRealBufferListener;
+import sample.real.RealBuffer;
+import alias.Metadata;
+import audio.metadata.AudioMetadata;
+import audio.metadata.IMetadataListener;
+import audio.squelch.ISquelchStateListener;
+import audio.squelch.SquelchState;
+import controller.channel.ChannelEvent;
+import controller.channel.IChannelEventListener;
+import dsp.filter.Filters;
+import dsp.filter.dc.AveragingDCRemovalFilter_RB;
+import dsp.filter.dc.DCRemovalFilter_RB;
+import dsp.filter.fir.real.RealFIRFilter_R_R;
+
+/**
+ * Provides packaging of demodulated audio sample buffers into audio packets for 
+ * broadcast to registered audio packet listeners.  Includes audio packet 
+ * metadata in constructed audio packets.
+ * 
+ * Incorporates audio squelch state listener to control if audio packets are
+ * broadcast or ignored.
+ */
+public class AudioModule extends Module implements IAudioPacketProvider, 
+												   IChannelEventListener,
+												   IMetadataListener, 
+												   IRealBufferListener, 
+												   ISquelchStateListener,
+												   Listener<RealBuffer>
+{
+	protected static final Logger mLog = LoggerFactory.getLogger( AudioModule.class );
+	
+	/* Determines responsiveness of DC filter to frequency changes */
+	private static final float DC_REMOVAL_RATIO = 0.000003f;
+
+	/* Provides a unique identifier for this audio module instance to use as a
+	 * source identifier for all audio packets */
+	private static int UNIQUE_ID = 0;
+	private int mSourceID;
+	
+	private AudioMetadata mAudioMetadata;
+
+	private ChannelEventListener mChannelEventListener = new ChannelEventListener();
+	
+	private SquelchStateListener mSquelchStateListener = new SquelchStateListener();
+	private SquelchState mSquelchState = SquelchState.SQUELCH;
+	
+	private RealFIRFilter_R_R mAudioFilter = new RealFIRFilter_R_R( 
+					Filters.FIR_BANDPASS_AUDIO_48KHZ.getCoefficients(), 2.0f );
+
+	private DCRemovalFilter_RB mDCRemovalFilter;
+	
+	private Listener<AudioPacket> mAudioPacketListener;
+	
+	private boolean mRemoveDC = false;
+	
+	public AudioModule()
+	{
+		this( false );
+	}
+	
+	public AudioModule( boolean removeDC )
+	{
+		mSourceID = ++UNIQUE_ID;
+		
+		mAudioMetadata = new AudioMetadata( mSourceID );
+		
+		mRemoveDC = removeDC;
+		
+		if( mRemoveDC )
+		{
+			mDCRemovalFilter = new AveragingDCRemovalFilter_RB( DC_REMOVAL_RATIO );
+			mDCRemovalFilter.setListener( this );
+		}
+	}
+	
+	@Override
+	public void dispose()
+	{
+		mSquelchStateListener = null;
+		mAudioPacketListener = null;
+	}
+
+	@Override
+	public void init()
+	{
+		mAudioMetadata.reset();
+	}
+
+	/**
+	 * Processes demodulated audio samples into audio packets with current audio
+	 * metadata and sends to the registered listener
+	 */
+	@Override
+	public void receive( RealBuffer buffer )
+	{
+		if( mAudioPacketListener != null && mSquelchState == SquelchState.UNSQUELCH )
+		{
+			float[] audio = buffer.getSamples();
+			
+			mAudioFilter.filter( audio );
+			
+			AudioPacket packet = new AudioPacket( audio, mAudioMetadata.copyOf() );
+			
+			mAudioPacketListener.receive( packet );
+		}
+	}
+
+	@Override
+	public Listener<RealBuffer> getRealBufferListener()
+	{
+		if( mRemoveDC )
+		{
+			return mDCRemovalFilter;
+		}
+		
+		return this;
+	}
+
+	@Override
+	public Listener<Metadata> getMetadataListener()
+	{
+		return mAudioMetadata;
+	}
+
+	@Override
+	public void setAudioPacketListener( Listener<AudioPacket> listener )
+	{
+		mAudioPacketListener = listener;
+	}
+
+	@Override
+	public void removeAudioPacketListener()
+	{
+		mAudioPacketListener = null;
+	}
+
+	@Override
+	public Listener<ChannelEvent> getChannelEventListener()
+	{
+		return mChannelEventListener;
+	}
+
+	@Override
+	public Listener<SquelchState> getSquelchStateListener()
+	{
+		return mSquelchStateListener;
+	}
+
+	/**
+	 * Wrapper for channel event listener.  Responds to channel state reset
+	 * events to remove/cleanup current audio metadata
+	 */
+	public class ChannelEventListener implements Listener<ChannelEvent>
+	{
+		@Override
+		public void receive( ChannelEvent event )
+		{
+			switch( event.getEvent() )
+			{
+				case CHANNEL_STATE_RESET:
+					mAudioMetadata.reset();
+					break;
+				case CHANGE_SELECTED:
+					mAudioMetadata.setSelected( event.getChannel().isSelected() );
+					break;
+				default:
+					break;
+			}
+		}
+	}
+
+	/**
+	 * Wrapper for squelch state listener
+	 */
+	public class SquelchStateListener implements Listener<SquelchState>
+	{
+		@Override
+		public void receive( SquelchState state )
+		{
+			mSquelchState = state;
+		}
+	}
+}