diff --git a/av/pubsub/queue.go b/av/pubsub/queue.go
index 6727ce7..2d312c4 100644
--- a/av/pubsub/queue.go
+++ b/av/pubsub/queue.go
@@ -49,41 +49,43 @@ func NewQueue(streams []av.CodecData) *Queue {
 // Set max buffered total packets duration.
 func (self *Queue) SetMaxDuration(dur time.Duration) {
 	self.lock.Lock()
-	defer self.lock.Unlock()
 
 	self.maxdur = dur
 	for self.maxdur > 0 && len(self.pkts) >= 2 && self.pkts[len(self.pkts)-1].Time - self.pkts[0].Time > self.maxdur {
 		self.pkts = self.pkts[1:]
 		self.head++
 	}
+
+	self.lock.Unlock()
 	return
 }
 
 // Currently buffered packets total duration.
 func (self *Queue) Duration() (dur time.Duration) {
 	self.lock.RLock()
-	defer self.lock.RUnlock()
 
 	if len(self.pkts) >= 2 {
 		dur = self.pkts[len(self.pkts)-1].Time - self.pkts[0].Time
 	}
+
+	self.lock.RUnlock()
 	return
 }
 
 // After Close() called, all QueueCursor's ReadPacket will return io.EOF.
 func (self *Queue) Close() (err error) {
 	self.lock.Lock()
-	defer self.lock.Unlock()
 
 	self.closed = true
 	self.cond.Broadcast()
+
+	self.lock.Unlock()
 	return
 }
 
 // Put packet into buffer, old packets will be discared.
 func (self *Queue) WritePacket(pkt av.Packet) (err error) {
 	self.lock.Lock()
-	defer self.lock.Unlock()
 
 	if self.maxdur > 0 && len(self.pkts) >= 2 && self.pkts[len(self.pkts)-1].Time - self.pkts[0].Time > self.maxdur {
 		self.pkts = self.pkts[1:]
@@ -92,6 +94,8 @@ func (self *Queue) WritePacket(pkt av.Packet) (err error) {
 	self.pkts = append(self.pkts, pkt)
 	self.tail++
 	self.cond.Broadcast()
+
+	self.lock.Unlock()
 	return
 }
 
@@ -164,9 +168,8 @@ func (self *Queue) DelayedGopCount(n int) *QueueCursor {
 
 func (self *QueueCursor) Streams() (streams []av.CodecData, err error) {
 	self.que.lock.RLock()
-	defer self.que.lock.RUnlock()
-
 	streams = self.que.streams
+	self.que.lock.RUnlock()
 	return
 }