diff --git a/removeads.py b/removeads.py
index 28c0260..d1cd0e6 100755
--- a/removeads.py
+++ b/removeads.py
@@ -250,6 +250,18 @@ def getTSFrame(frame):
     ts = timedelta(seconds=pts_time)
     return ts
 
+def getPacketDuration(packet):
+    if 'duration' in packet:
+        duration = int(packet['duration'])
+    elif 'pkt_duration' in packet:
+        duration = int(packet['pkt_duration'])
+    else:
+        logger.error('Impossible to find duration of packet %s' % packet)
+        return None
+    
+    return duration
+    
+
 def getFramesInStream(inputFile, begin, end, streamKind, subStreamId=0):
     logger = logging.getLogger(__name__)
     infd = inputFile.fileno()
@@ -537,7 +549,9 @@ def extractAllStreams(inputFile, begin, end, streams, filesPrefix, nbFrames, wid
                 nbPackets = len(packets)
                 logger.debug("Found %d packets to be extracted from audio track." % nbPackets)
                 if(nbPackets > 0):
-                    packetDuration = packets[0]['duration']
+                    packetDuration = getPacketDuration(packets[0])
+                    if packetDuration == None:
+                        return None
                 
                 tmpname = '%s-%d.pcm' % (filesPrefix,audioID)