jitterbuffer: Improve performance

Rework the jittebuffer for SampleBuilder use

pkg/jitterbuffer/jitter_buffer.go

@@ -66,7 +66,7 @@ type (
 // order, and allows removing in either sequence number order or via a
 // provided timestamp.
 type JitterBuffer struct {
-	packets       *PriorityQueue
+	packets       *RBTree
 	minStartCount uint16
 	lastSequence  uint16
 	playoutHead   uint16
@@ -253,8 +253,6 @@ func (jb *JitterBuffer) PopAtSequence(sq uint16) (*rtp.Packet, error) {
 // PeekAtSequence will return an RTP packet from the jitter buffer at the specified Sequence
 // without removing it from the buffer.
 func (jb *JitterBuffer) PeekAtSequence(sq uint16) (*rtp.Packet, error) {
-	jb.mutex.Lock()
-	defer jb.mutex.Unlock()
 	packet, err := jb.packets.Find(sq)
 	if err != nil {
 		return nil, err

pkg/jitterbuffer/jitter_buffer_test.go

@@ -132,6 +132,7 @@ func TestJitterBuffer(t *testing.T) {
 		assert.Equal(jb.packets.Length(), uint16(100))
 		assert.Equal(jb.state, Emitting)
 		head, err := jb.PopAtTimestamp(uint32(513))
+		assert.NotNil(head)
 		assert.Equal(head.SequenceNumber, uint16(math.MaxUint16-32+1))
 		assert.Equal(err, nil)
 		head, err = jb.PopAtTimestamp(uint32(513))