From c2401e7a75cc738215e3b7c9958cdec1b552a35f Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sat, 12 Jul 2014 12:21:57 -0700
Subject: [PATCH] Remove object allocations from audio decoding path

---
 .../com/limelight/nvstream/av/RtpPacket.java  | 26 ++++++++++++-------
 .../nvstream/av/audio/AudioDepacketizer.java  |  7 +++--
 .../nvstream/av/audio/AudioStream.java        |  9 ++++---
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/moonlight-common/src/com/limelight/nvstream/av/RtpPacket.java b/moonlight-common/src/com/limelight/nvstream/av/RtpPacket.java
index 1e60a728..0d0d15ed 100644
--- a/moonlight-common/src/com/limelight/nvstream/av/RtpPacket.java
+++ b/moonlight-common/src/com/limelight/nvstream/av/RtpPacket.java
@@ -1,29 +1,37 @@
 package com.limelight.nvstream.av;
 
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 
 public class RtpPacket {
 	
 	private byte packetType;
 	private short seqNum;
+	
 	private ByteBufferDescriptor buffer;
+	private ByteBuffer bb;
 	
 	public static final int HEADER_SIZE = 12;
 	
-	public RtpPacket(ByteBufferDescriptor buffer)
+	public RtpPacket(byte[] buffer)
+	{
+		this.buffer = new ByteBufferDescriptor(buffer, 0, buffer.length);
+		this.bb = ByteBuffer.wrap(buffer).order(ByteOrder.BIG_ENDIAN);
+	}
+	
+	public void initializeWithLength(int length)
 	{
-		this.buffer = new ByteBufferDescriptor(buffer);
-		
-		ByteBuffer bb = ByteBuffer.wrap(buffer.data, buffer.offset, buffer.length);
-		
 		// Discard the first byte
-		bb.position(bb.position()+1);
+		bb.position(1);
 		
 		// Get the packet type
 		packetType = bb.get();
 		
 		// Get the sequence number
 		seqNum = bb.getShort();
+		
+		// Update descriptor length
+		buffer.length = length;
 	}
 	
 	public byte getPacketType()
@@ -36,13 +44,13 @@ public class RtpPacket {
 		return seqNum;
 	}
 	
-	public byte[] getBackingBuffer()
+	public byte[] getBuffer()
 	{
 		return buffer.data;
 	}
 	
-	public ByteBufferDescriptor getNewPayloadDescriptor()
+	public void initializePayloadDescriptor(ByteBufferDescriptor bb)
 	{
-		return new ByteBufferDescriptor(buffer.data, buffer.offset+HEADER_SIZE, buffer.length-HEADER_SIZE);
+		bb.reinitialize(buffer.data, buffer.offset+HEADER_SIZE, buffer.length-HEADER_SIZE);
 	}
 }
diff --git a/moonlight-common/src/com/limelight/nvstream/av/audio/AudioDepacketizer.java b/moonlight-common/src/com/limelight/nvstream/av/audio/AudioDepacketizer.java
index 1002589c..d8a6a707 100644
--- a/moonlight-common/src/com/limelight/nvstream/av/audio/AudioDepacketizer.java
+++ b/moonlight-common/src/com/limelight/nvstream/av/audio/AudioDepacketizer.java
@@ -20,6 +20,9 @@ public class AudioDepacketizer {
 	private byte[][] pcmRing;
 	private int ringIndex;
 	
+	// Cached objects
+	private ByteBufferDescriptor cachedDesc = new ByteBufferDescriptor(null, 0, 0);
+	
 	// Sequencing state
 	private short lastSequenceNumber;
 	
@@ -88,8 +91,8 @@ public class AudioDepacketizer {
 		lastSequenceNumber = seq;
 		
 		// This is all the depacketizing we need to do
-		ByteBufferDescriptor rtpPayload = packet.getNewPayloadDescriptor();
-		decodeData(rtpPayload.data, rtpPayload.offset, rtpPayload.length);
+		packet.initializePayloadDescriptor(cachedDesc);
+		decodeData(cachedDesc.data, cachedDesc.offset, cachedDesc.length);
 	}
 	
 	public ByteBufferDescriptor getNextDecodedData() throws InterruptedException
diff --git a/moonlight-common/src/com/limelight/nvstream/av/audio/AudioStream.java b/moonlight-common/src/com/limelight/nvstream/av/audio/AudioStream.java
index 1b73188c..5aa3fe15 100644
--- a/moonlight-common/src/com/limelight/nvstream/av/audio/AudioStream.java
+++ b/moonlight-common/src/com/limelight/nvstream/av/audio/AudioStream.java
@@ -152,17 +152,18 @@ public class AudioStream {
 		Thread t = new Thread() {
 			@Override
 			public void run() {
-				ByteBufferDescriptor desc = new ByteBufferDescriptor(new byte[MAX_PACKET_SIZE], 0, MAX_PACKET_SIZE);
-				DatagramPacket packet = new DatagramPacket(desc.data, desc.length);
+				byte[] buffer = new byte[MAX_PACKET_SIZE];
+				DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
+				RtpPacket rtpPacket = new RtpPacket(buffer);
 				
 				while (!isInterrupted())
 				{
 					try {
 						rtp.receive(packet);
-						desc.length = packet.getLength();
 						
 						// DecodeInputData() doesn't hold onto the buffer so we are free to reuse it
-						depacketizer.decodeInputData(new RtpPacket(desc));
+						rtpPacket.initializeWithLength(packet.getLength());
+						depacketizer.decodeInputData(rtpPacket);
 						
 						packet.setLength(MAX_PACKET_SIZE);
 					} catch (IOException e) {