diff -r f5a5d9237d69 -r e8d6255306f8 src/org/sipdroid/net/RtpPacket.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/sipdroid/net/RtpPacket.java	Sat Jan 23 22:19:43 2010 +0100
@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2009 The Sipdroid Open Source Project
+ * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
+ * 
+ * This file is part of Sipdroid (http://www.sipdroid.org)
+ * 
+ * Sipdroid is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This source code is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this source code; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+package src.org.sipdroid.net;
+
+import org.zoolu.tools.Random;
+
+/**
+ * RtpPacket implements a RTP packet.
+ */
+public class RtpPacket {
+	/* RTP packet buffer containing both the RTP header and payload */
+	byte[] packet;
+
+	/* RTP packet length */
+	int packet_len;
+
+	/* RTP header length */
+	// int header_len;
+	/** Gets the RTP packet */
+	public byte[] getPacket() {
+		return packet;
+	}
+
+	/** Gets the RTP packet length */
+	public int getLength() {
+		return packet_len;
+	}
+
+	/** Gets the RTP header length */
+	public int getHeaderLength() {
+		if (packet_len >= 12)
+			return 12 + 4 * getCscrCount();
+		else
+			return packet_len; // broken packet
+	}
+
+	/** Gets the RTP header length */
+	public int getPayloadLength() {
+		if (packet_len >= 12)
+			return packet_len - getHeaderLength();
+		else
+			return 0; // broken packet
+	}
+
+	/** Sets the RTP payload length */
+	public void setPayloadLength(int len) {
+		packet_len = getHeaderLength() + len;
+	}
+
+	// version (V): 2 bits
+	// padding (P): 1 bit
+	// extension (X): 1 bit
+	// CSRC count (CC): 4 bits
+	// marker (M): 1 bit
+	// payload type (PT): 7 bits
+	// sequence number: 16 bits
+	// timestamp: 32 bits
+	// SSRC: 32 bits
+	// CSRC list: 0 to 15 items, 32 bits each
+
+	/** Gets the version (V) */
+	public int getVersion() {
+		if (packet_len >= 12)
+			return (packet[0] >> 6 & 0x03);
+		else
+			return 0; // broken packet
+	}
+
+	/** Sets the version (V) */
+	public void setVersion(int v) {
+		if (packet_len >= 12)
+			packet[0] = (byte) ((packet[0] & 0x3F) | ((v & 0x03) << 6));
+	}
+
+	/** Whether has padding (P) */
+	public boolean hasPadding() {
+		if (packet_len >= 12)
+			return getBit(packet[0], 5);
+		else
+			return false; // broken packet
+	}
+
+	/** Set padding (P) */
+	public void setPadding(boolean p) {
+		if (packet_len >= 12)
+			packet[0] = setBit(p, packet[0], 5);
+	}
+
+	/** Whether has extension (X) */
+	public boolean hasExtension() {
+		if (packet_len >= 12)
+			return getBit(packet[0], 4);
+		else
+			return false; // broken packet
+	}
+
+	/** Set extension (X) */
+	public void setExtension(boolean x) {
+		if (packet_len >= 12)
+			packet[0] = setBit(x, packet[0], 4);
+	}
+
+	/** Gets the CSCR count (CC) */
+	public int getCscrCount() {
+		if (packet_len >= 12)
+			return (packet[0] & 0x0F);
+		else
+			return 0; // broken packet
+	}
+
+	/** Whether has marker (M) */
+	public boolean hasMarker() {
+		if (packet_len >= 12)
+			return getBit(packet[1], 7);
+		else
+			return false; // broken packet
+	}
+
+	/** Set marker (M) */
+	public void setMarker(boolean m) {
+		if (packet_len >= 12)
+			packet[1] = setBit(m, packet[1], 7);
+	}
+
+	/** Gets the payload type (PT) */
+	public int getPayloadType() {
+		if (packet_len >= 12)
+			return (packet[1] & 0x7F);
+		else
+			return -1; // broken packet
+	}
+
+	/** Sets the payload type (PT) */
+	public void setPayloadType(int pt) {
+		if (packet_len >= 12)
+			packet[1] = (byte) ((packet[1] & 0x80) | (pt & 0x7F));
+	}
+
+	/** Gets the sequence number */
+	public int getSequenceNumber() {
+		if (packet_len >= 12)
+			return getInt(packet, 2, 4);
+		else
+			return 0; // broken packet
+	}
+
+	/** Sets the sequence number */
+	public void setSequenceNumber(int sn) {
+		if (packet_len >= 12)
+			setInt(sn, packet, 2, 4);
+	}
+
+	/** Gets the timestamp */
+	public long getTimestamp() {
+		if (packet_len >= 12)
+			return getLong(packet, 4, 8);
+		else
+			return 0; // broken packet
+	}
+
+	/** Sets the timestamp */
+	public void setTimestamp(long timestamp) {
+		if (packet_len >= 12)
+			setLong(timestamp, packet, 4, 8);
+	}
+
+	/** Gets the SSCR */
+	public long getSscr() {
+		if (packet_len >= 12)
+			return getLong(packet, 8, 12);
+		else
+			return 0; // broken packet
+	}
+
+	/** Sets the SSCR */
+	public void setSscr(long ssrc) {
+		if (packet_len >= 12)
+			setLong(ssrc, packet, 8, 12);
+	}
+
+	/** Gets the CSCR list */
+	public long[] getCscrList() {
+		int cc = getCscrCount();
+		long[] cscr = new long[cc];
+		for (int i = 0; i < cc; i++)
+			cscr[i] = getLong(packet, 12 + 4 * i, 16 + 4 * i);
+		return cscr;
+	}
+
+	/** Sets the CSCR list */
+	public void setCscrList(long[] cscr) {
+		if (packet_len >= 12) {
+			int cc = cscr.length;
+			if (cc > 15)
+				cc = 15;
+			packet[0] = (byte) (((packet[0] >> 4) << 4) + cc);
+			cscr = new long[cc];
+			for (int i = 0; i < cc; i++)
+				setLong(cscr[i], packet, 12 + 4 * i, 16 + 4 * i);
+			// header_len=12+4*cc;
+		}
+	}
+
+	/** Sets the payload */
+	public void setPayload(byte[] payload, int len) {
+		if (packet_len >= 12) {
+			int header_len = getHeaderLength();
+			for (int i = 0; i < len; i++)
+				packet[header_len + i] = payload[i];
+			packet_len = header_len + len;
+		}
+	}
+
+	/** Gets the payload */
+	public byte[] getPayload() {
+		int header_len = getHeaderLength();
+		int len = packet_len - header_len;
+		byte[] payload = new byte[len];
+		for (int i = 0; i < len; i++)
+			payload[i] = packet[header_len + i];
+		return payload;
+	}
+
+	/** Creates a new RTP packet */
+	public RtpPacket(byte[] buffer, int packet_length) {
+		packet = buffer;
+		packet_len = packet_length;
+		if (packet_len < 12)
+			packet_len = 12;
+		init(0x0F);
+	}
+
+	/** init the RTP packet header (only PT) */
+	public void init(int ptype) {
+		init(ptype, Random.nextLong());
+	}
+
+	/** init the RTP packet header (PT and SSCR) */
+	public void init(int ptype, long sscr) {
+		init(ptype, Random.nextInt(), Random.nextLong(), sscr);
+	}
+
+	/** init the RTP packet header (PT, SQN, TimeStamp, SSCR) */
+	public void init(int ptype, int seqn, long timestamp, long sscr) {
+		setVersion(2);
+		setPayloadType(ptype);
+		setSequenceNumber(seqn);
+		setTimestamp(timestamp);
+		setSscr(sscr);
+	}
+
+	// *********************** Private and Static ***********************
+
+	/** Gets int value */
+	private static int getInt(byte b) {
+		return ((int) b + 256) % 256;
+	}
+
+	/** Gets long value */
+	private static long getLong(byte[] data, int begin, int end) {
+		long n = 0;
+		for (; begin < end; begin++) {
+			n <<= 8;
+			n += data[begin];
+		}
+		return n;
+	}
+
+	/** Sets long value */
+	private static void setLong(long n, byte[] data, int begin, int end) {
+		for (end--; end >= begin; end--) {
+			data[end] = (byte) (n % 256);
+			n >>= 8;
+		}
+	}
+
+	/** Gets Int value */
+	private static int getInt(byte[] data, int begin, int end) {
+		return (int) getLong(data, begin, end);
+	}
+
+	/** Sets Int value */
+	private static void setInt(int n, byte[] data, int begin, int end) {
+		setLong(n, data, begin, end);
+	}
+
+	/** Gets bit value */
+	private static boolean getBit(byte b, int bit) {
+		return (b >> bit) == 1;
+	}
+
+	/** Sets bit value */
+	private static byte setBit(boolean value, byte b, int bit) {
+		if (value)
+			return (byte) (b | (1 << bit));
+		else
+			return (byte) ((b | (1 << bit)) ^ (1 << bit));
+	}
+}