Increase resilience to packet loss. IDR frames are no longer requested if error correction data was lost. A maximum of one IDR frame is requested per corrupt frame. Error correction data is used to recover from the loss of a single-packet frame.

moonlight-common/src/com/limelight/nvstream/av/ConnectionStatusListener.java

@@ -3,7 +3,7 @@ package com.limelight.nvstream.av;
 public interface ConnectionStatusListener {
 	public void connectionTerminated();
 	
-	public void connectionDetectedPacketLoss();
+	public void connectionDetectedFrameLoss(int firstLostFrame, int lastLostFrame);
 	
-	public void connectionSinkTooSlow();
+	public void connectionSinkTooSlow(int firstLostFrame, int lastLostFrame);
 }

moonlight-common/src/com/limelight/nvstream/av/DecodeUnit.java

@@ -11,13 +11,15 @@ public class DecodeUnit {
 	private List<ByteBufferDescriptor> bufferList;
 	private int dataLength;
 	private int flags;
+	private int frameNumber;
 	
-	public DecodeUnit(int type, List<ByteBufferDescriptor> bufferList, int dataLength, int flags)
+	public DecodeUnit(int type, List<ByteBufferDescriptor> bufferList, int dataLength, int flags, int frameNumber)
 	{
 		this.type = type;
 		this.bufferList = bufferList;
 		this.dataLength = dataLength;
 		this.flags = flags;
+		this.frameNumber = frameNumber;
 	}
 	
 	public int getType()
@@ -39,4 +41,9 @@ public class DecodeUnit {
 	{
 		return dataLength;
 	}
+	
+	public int getFrameNumber()
+	{
+		return frameNumber;
+	}
 }

moonlight-common/src/com/limelight/nvstream/av/video/VideoDepacketizer.java

@@ -10,13 +10,16 @@ import com.limelight.nvstream.av.ConnectionStatusListener;
 
 public class VideoDepacketizer {
 	
-	// Current NAL state
-	private LinkedList<ByteBufferDescriptor> avcNalDataChain = null;
-	private int avcNalDataLength = 0;
+	// Current frame state
+	private LinkedList<ByteBufferDescriptor> avcFrameDataChain = null;
+	private int avcFrameDataLength = 0;
 	private int currentlyDecoding = DecodeUnit.TYPE_UNKNOWN;
 	
 	// Sequencing state
-	private short lastSequenceNumber;
+	private int nextFrameNumber = 1;
+	private int nextPacketNumber;
+	private int startFrameNumber = 1;
+	private boolean waitingForFrameStart;
 	
 	// Cached objects
 	private ByteBufferDescriptor cachedDesc = new ByteBufferDescriptor(null, 0, 0);
@@ -33,31 +36,31 @@ public class VideoDepacketizer {
 		this.controlListener = controlListener;
 	}
 	
-	private void clearAvcNalState()
+	private void clearAvcFrameState()
 	{
-		avcNalDataChain = null;
-		avcNalDataLength = 0;
+		avcFrameDataChain = null;
+		avcFrameDataLength = 0;
 	}
 
-	private void reassembleAvcNal()
+	private void reassembleAvcFrame(int frameNumber)
 	{
-		// This is the start of a new NAL
-		if (avcNalDataChain != null && avcNalDataLength != 0) {
+		// This is the start of a new frame
+		if (avcFrameDataChain != null && avcFrameDataLength != 0) {
 			// Construct the H264 decode unit
-			DecodeUnit du = new DecodeUnit(DecodeUnit.TYPE_H264, avcNalDataChain, avcNalDataLength, 0);
+			DecodeUnit du = new DecodeUnit(DecodeUnit.TYPE_H264, avcFrameDataChain, avcFrameDataLength, 0, frameNumber);
 			if (directSubmitDr != null) {
 				// Submit directly to the decoder
 				directSubmitDr.submitDecodeUnit(du);
 			}
 			else if (!decodedUnits.offer(du)) {
-				// We need a new IDR frame since we're discarding data now
 				System.out.println("Video decoder is too slow! Forced to drop decode units");
+				// Invalidate all frames from the start of the DU queue to this frame number
+				controlListener.connectionSinkTooSlow(decodedUnits.remove().getFrameNumber(), frameNumber);
 				decodedUnits.clear();
-				controlListener.connectionSinkTooSlow();
 			}
 
 			// Clear old state
-			clearAvcNalState();
+			clearAvcFrameState();
 		}
 	}
 	
@@ -80,11 +83,11 @@ public class VideoDepacketizer {
 					if (NAL.isAvcFrameStart(cachedDesc))
 					{
 						// Reassemble any pending AVC NAL
-						reassembleAvcNal();
+						reassembleAvcFrame(packet.getFrameIndex());
 
 						// Setup state for the new NAL
-						avcNalDataChain = new LinkedList<ByteBufferDescriptor>();
-						avcNalDataLength = 0;
+						avcFrameDataChain = new LinkedList<ByteBufferDescriptor>();
+						avcFrameDataLength = 0;
 					}
 
 					// Skip the start sequence
@@ -97,7 +100,7 @@ public class VideoDepacketizer {
 					if (currentlyDecoding == DecodeUnit.TYPE_H264 &&
 						NAL.isPadding(cachedDesc)) {
 						// The decode unit is complete
-						reassembleAvcNal();
+						reassembleAvcFrame(packet.getFrameIndex());
 					}
 
 					// Not decoding AVC
@@ -133,13 +136,13 @@ public class VideoDepacketizer {
 				location.length--;
 			}
 
-			if (currentlyDecoding == DecodeUnit.TYPE_H264 && avcNalDataChain != null)
+			if (currentlyDecoding == DecodeUnit.TYPE_H264 && avcFrameDataChain != null)
 			{
 				ByteBufferDescriptor data = new ByteBufferDescriptor(location.data, start, location.offset-start);
 
 				// Add a buffer descriptor describing the NAL data in this packet
-				avcNalDataChain.add(data);
-				avcNalDataLength += location.offset-start;
+				avcFrameDataChain.add(data);
+				avcFrameDataLength += location.offset-start;
 			}
 		}
 	}
@@ -148,15 +151,13 @@ public class VideoDepacketizer {
 	{
 		if (firstPacket) {
 			// Setup state for the new frame
-			avcNalDataChain = new LinkedList<ByteBufferDescriptor>();
-			avcNalDataLength = 0;
+			avcFrameDataChain = new LinkedList<ByteBufferDescriptor>();
+			avcFrameDataLength = 0;
 		}
 		
 		// Add the payload data to the chain
-		if (avcNalDataChain != null) {
-			avcNalDataChain.add(location);
-			avcNalDataLength += location.length;
-		}
+		avcFrameDataChain.add(location);
+		avcFrameDataLength += location.length;
 	}
 	
 	public void addInputData(VideoPacket packet)
@@ -164,29 +165,87 @@ public class VideoDepacketizer {
 		ByteBufferDescriptor location = packet.getNewPayloadDescriptor();
 		
 		// Runt packets get decoded using the slow path
+		// These packets stand alone so there's no need to verify
+		// sequencing before submitting
 		if (location.length < 968) {
 			addInputDataSlow(packet, location);
             return;
 		}
 		
+		int frameIndex = packet.getFrameIndex();
 		int packetIndex = packet.getPacketIndex();
 		int packetsInFrame = packet.getTotalPackets();
 		
+		// We can use FEC to correct single packet errors
+		// on single packet frames because we just get a
+		// duplicate of the original packet
+		if (packetsInFrame == 1 && packetIndex == 1 &&
+			nextPacketNumber == 0 && frameIndex == nextFrameNumber) {
+			System.out.println("Using FEC for error correction");
+			nextPacketNumber = 1;
+		}
 		// Discard FEC data early
-		if (packetIndex >= packetsInFrame) {
+		else if (packetIndex >= packetsInFrame) {
 			return;
 		}
 		
+		// Check that this is the next frame
+		boolean firstPacket = (packet.getFlags() & VideoPacket.FLAG_SOF) != 0;
+		if (firstPacket && waitingForFrameStart) {
+			// This is the next frame after a loss event
+			controlListener.connectionDetectedFrameLoss(startFrameNumber, frameIndex - 1);
+			startFrameNumber = nextFrameNumber = frameIndex;
+			nextPacketNumber = 0;
+			waitingForFrameStart = false;
+			clearAvcFrameState();
+		}
+		else if (frameIndex > nextFrameNumber) {
+			// Nope, but we can still work with it if it's
+			// the start of the next frame
+			if (firstPacket) {
+				System.out.println("Got start of frame "+frameIndex+
+						" when expecting packet "+nextPacketNumber+
+						" of frame "+nextFrameNumber);
+				controlListener.connectionDetectedFrameLoss(startFrameNumber, frameIndex - 1);
+				startFrameNumber = nextFrameNumber = frameIndex;
+				nextPacketNumber = 0;
+				clearAvcFrameState();
+			}
+			else {
+				System.out.println("Got packet "+packetIndex+" of frame "+frameIndex+
+						" when expecting packet "+nextPacketNumber+
+						" of frame "+nextFrameNumber);
+				// We dropped the start of this frame too, so pick up on the next frame
+				waitingForFrameStart = true;
+				return;
+			}
+		}
+		else if (frameIndex < nextFrameNumber) {
+			System.out.println("Frame "+frameIndex+" is behind our current frame number "+nextFrameNumber);
+			// Discard the frame silently if it's behind our current sequence number
+			return;
+		}
+		
+		// We know it's the right frame, now check the packet number
+		if (packetIndex != nextPacketNumber) {
+			System.out.println("Frame "+frameIndex+": expected packet "+nextPacketNumber+" but got "+packetIndex);
+			// At this point, we're guaranteed that it's not FEC data that we lost
+			waitingForFrameStart = true;
+			return;
+		}
+		
+		nextPacketNumber++;
+		
 		// Remove extra padding
 		location.length = packet.getPayloadLength();
-		
-		boolean firstPacket = (packet.getFlags() & VideoPacket.FLAG_SOF) != 0;
+				
 		if (firstPacket)
 		{
 			if (NAL.getSpecialSequenceDescriptor(location, cachedDesc) && NAL.isAvcFrameStart(cachedDesc)
 				&& cachedDesc.data[cachedDesc.offset+cachedDesc.length] == 0x67)
 			{
 				// SPS and PPS prefix is padded between NALs, so we must decode it with the slow path
+				clearAvcFrameState();
 				addInputDataSlow(packet, location);
 				return;
 			}
@@ -194,32 +253,21 @@ public class VideoDepacketizer {
 
 		addInputDataFast(packet, location, firstPacket);
 		
+		// We can't use the EOF flag here because real frames can be split across
+		// multiple "frames" when packetized to fit under the bandwidth ceiling
+		if (packetIndex + 1 >= packetsInFrame) {
+	        nextFrameNumber++;
+	        nextPacketNumber = 0;
+		}
+		
 		if ((packet.getFlags() & VideoPacket.FLAG_EOF) != 0) {
-	        reassembleAvcNal();
+	        reassembleAvcFrame(packet.getFrameIndex());
+	        startFrameNumber = nextFrameNumber;
 		}
 	}
 	
 	public void addInputData(RtpPacket packet)
 	{
-		short seq = packet.getSequenceNumber();
-		
-		// Toss out the current NAL if we receive a packet that is
-		// out of sequence
-		if (lastSequenceNumber != 0 &&
-			(short)(lastSequenceNumber + 1) != seq)
-		{
-			System.out.println("Received OOS video data (expected "+(lastSequenceNumber + 1)+", got "+seq+")");
-			
-			// Reset the depacketizer state
-			clearAvcNalState();
-			
-			// Request an IDR frame
-			controlListener.connectionDetectedPacketLoss();
-		}
-		
-		lastSequenceNumber = seq;
-		
-		// Pass the payload to the non-sequencing parser
 		ByteBufferDescriptor rtpPayload = packet.getNewPayloadDescriptor();
 		addInputData(new VideoPacket(rtpPayload));
 	}

moonlight-common/src/com/limelight/nvstream/control/ControlStream.java

@@ -8,6 +8,7 @@ import java.net.InetSocketAddress;
 import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.concurrent.LinkedBlockingQueue;
 
 import com.limelight.nvstream.NvConnectionListener;
 import com.limelight.nvstream.StreamConfiguration;
@@ -60,7 +61,7 @@ public class ControlStream implements ConnectionStatusListener {
 	private Thread heartbeatThread;
 	private Thread jitterThread;
 	private Thread resyncThread;
-	private Object resyncNeeded = new Object();
+	private LinkedBlockingQueue<int[]> invalidReferenceFrameTuples = new LinkedBlockingQueue<int[]>();
 	private boolean aborting = false;
 	
 	public ControlStream(InetAddress host, NvConnectionListener listener, StreamConfiguration streamConfig)
@@ -140,12 +141,6 @@ public class ControlStream implements ConnectionStatusListener {
 		}
 	}
 	
-	public void requestResync() throws IOException
-	{
-		System.out.println("CTL: Requesting IDR frame");
-		sendResync();
-	}
-	
 	public void start() throws IOException
 	{
 		// Use a finite timeout during the handshake process
@@ -188,18 +183,36 @@ public class ControlStream implements ConnectionStatusListener {
 			public void run() {
 				while (!isInterrupted())
 				{
+					int[] tuple;
+					
+					// Wait for a tuple
 					try {
-						// Wait for notification of a resync needed
-						synchronized (resyncNeeded) {
-							resyncNeeded.wait();
-						}
+						tuple = invalidReferenceFrameTuples.take();
 					} catch (InterruptedException e) {
 						listener.connectionTerminated(e);
 						return;
 					}
 					
+					// Aggregate all lost frames into one range
+					int[] lastTuple = null;
+					for (;;) {
+						int[] nextTuple = lastTuple = invalidReferenceFrameTuples.poll();
+						if (nextTuple == null) {
+							break;
+						}
+						
+						lastTuple = nextTuple;
+					}
+					
+					// Update the end of the range to the latest tuple
+					if (lastTuple != null) {
+						tuple[1] = lastTuple[1];
+					}
+					
 					try {
-						requestResync();
+						System.err.println("Invalidating reference frames from "+tuple[0]+" to "+tuple[1]);
+						ControlStream.this.sendResync(tuple[0], tuple[1]);
+						System.err.println("Frames invalidated");
 					} catch (IOException e) {
 						listener.connectionTerminated(e);
 						return;
@@ -243,12 +256,14 @@ public class ControlStream implements ConnectionStatusListener {
 		return sendAndGetReply(new NvCtlPacket(PTYPE_1405, PPAYLEN_1405));
 	}
 	
-	private void sendResync() throws IOException
+	private void sendResync(int firstLostFrame, int lastLostFrame) throws IOException
 	{
 		ByteBuffer conf = ByteBuffer.wrap(new byte[PPAYLEN_RESYNC]).order(ByteOrder.LITTLE_ENDIAN);
 		
 		conf.putLong(0);
 		conf.putLong(0xFFFFF);
+		//conf.putLong(firstLostFrame);
+		//conf.putLong(lastLostFrame);
 		
 		sendAndGetReply(new NvCtlPacket(PTYPE_RESYNC, PPAYLEN_RESYNC, conf.array()));
 	}
@@ -413,14 +428,11 @@ public class ControlStream implements ConnectionStatusListener {
 		abort();
 	}
 
-	private void resyncConnection() {
-		synchronized (resyncNeeded) {
-			// Wake up the resync thread
-			resyncNeeded.notify();
-		}
+	private void resyncConnection(int firstLostFrame, int lastLostFrame) {
+		invalidReferenceFrameTuples.add(new int[]{firstLostFrame, lastLostFrame});
 	}
 
-	public void connectionDetectedPacketLoss() {
+	public void connectionDetectedFrameLoss(int firstLostFrame, int lastLostFrame) {
 		if (System.currentTimeMillis() > LOSS_PERIOD_MS + lossTimestamp) {
 			lossCount++;
 			lossTimestamp = System.currentTimeMillis();
@@ -433,15 +445,15 @@ public class ControlStream implements ConnectionStatusListener {
 			}
 		}
 		
-		resyncConnection();
+		resyncConnection(firstLostFrame, lastLostFrame);
 	}
 
-	public void connectionSinkTooSlow() {
+	public void connectionSinkTooSlow(int firstLostFrame, int lastLostFrame) {
 		if (++slowSinkCount == MAX_SLOW_SINK_COUNT) {
 			listener.displayTransientMessage("Your device is processing the A/V data too slowly. Try lowering stream settings.");
 			slowSinkCount = -MAX_SLOW_SINK_COUNT * MESSAGE_DELAY_FACTOR;
 		}
 		
-		resyncConnection();
+		resyncConnection(firstLostFrame, lastLostFrame);
 	}
 }