diff --git a/src/net/java/sip/communicator/impl/neomedia/RawPacket.java b/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
index bf3e1c7fb..d1a787cb2 100755
--- a/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
+++ b/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
@@ -375,7 +375,11 @@ public int getPaddingSize()
      */
     public int getHeaderLength()
     {
-        return FIXED_HEADER_SIZE + 4 * getCsrcCount() + getExtensionLength();
+        if(getExtensionBit())
+            return FIXED_HEADER_SIZE + 4 * getCsrcCount()
+                + EXT_HEADER_SIZE + getExtensionLength();
+        else
+            return FIXED_HEADER_SIZE + 4 * getCsrcCount();
     }
 
     /**
diff --git a/src/net/java/sip/communicator/impl/neomedia/device/AudioMixerMediaDevice.java b/src/net/java/sip/communicator/impl/neomedia/device/AudioMixerMediaDevice.java
index b005c9600..3a4e35e99 100644
--- a/src/net/java/sip/communicator/impl/neomedia/device/AudioMixerMediaDevice.java
+++ b/src/net/java/sip/communicator/impl/neomedia/device/AudioMixerMediaDevice.java
@@ -302,7 +302,10 @@ else if (dataSource
                                 = streamAudioLevelListeners.get(receiveStream);
                         }
 
-                        if(streamEventDispatcher != null)
+                        if(streamEventDispatcher != null
+                            && !buffer.isDiscard()
+                            && buffer.getLength() > 0
+                            && buffer.getData() != null)
                         {
                             if(! streamEventDispatcher.isRunning())
                                 new Thread(streamEventDispatcher,
diff --git a/src/net/java/sip/communicator/impl/neomedia/transform/zrtp/ZRTPTransformEngine.java b/src/net/java/sip/communicator/impl/neomedia/transform/zrtp/ZRTPTransformEngine.java
index 62671ac9c..9044b2420 100644
--- a/src/net/java/sip/communicator/impl/neomedia/transform/zrtp/ZRTPTransformEngine.java
+++ b/src/net/java/sip/communicator/impl/neomedia/transform/zrtp/ZRTPTransformEngine.java
@@ -564,8 +564,6 @@ public RawPacket transform(RawPacket pkt)
         /*
          * Never transform outgoing ZRTP (invalid RTP) packets.
          */        
-        byte[] buffer = pkt.getBuffer();
-        int offset = pkt.getOffset();
         if (ZrtpRawPacket.isZrtpData(pkt))
         {
             return pkt;
@@ -574,7 +572,7 @@ public RawPacket transform(RawPacket pkt)
         // ZRTP needs the SSRC of the sending stream.
         if (enableZrtp && ownSSRC == 0)
         {
-            ownSSRC = (int)(pkt.readUnsignedIntAsLong(8) & 0xffffffff);
+            ownSSRC = pkt.getSSRC();
         }
 
         // If SRTP is active then srtpTransformer is set, use it.