Add instant start for WebRTC consumer

pkg/core/track.go

@@ -113,7 +113,12 @@ func NewSender(media *Media, codec *Codec) *Sender {
 type HandlerFunc func(packet *rtp.Packet)
 
 func (s *Sender) HandleRTP(track *Receiver) {
-	bufferSize := 100
+	s.Bind(track)
+	go s.worker(track)
+}
+
+func (s *Sender) Bind(track *Receiver) {
+	var bufferSize uint16
 
 	if GetKind(track.Codec.Name) == KindVideo {
 		if track.Codec.IsRTP() {
@@ -123,6 +128,8 @@ func (s *Sender) HandleRTP(track *Receiver) {
 		} else {
 			bufferSize = 50
 		}
+	} else {
+		bufferSize = 100
 	}
 
 	buffer := make(chan *rtp.Packet, bufferSize)
@@ -133,28 +140,43 @@ func (s *Sender) HandleRTP(track *Receiver) {
 	}
 	track.senders[s] = buffer
 	track.mu.Unlock()
+
 	s.mu.Lock()
 	s.receivers = append(s.receivers, track)
 	s.mu.Unlock()
+}
 
-	go func() {
-		// read packets from buffer channel until it will be closed
+func (s *Sender) worker(track *Receiver) {
+	track.mu.Lock()
+	buffer := track.senders[s]
+	track.mu.Unlock()
+
+	// read packets from buffer channel until it will be closed
+	if buffer != nil {
 		for packet := range buffer {
 			s.bytes += len(packet.Payload)
 			s.Handler(packet)
 		}
+	}
 
-		// remove current receiver from list
-		// it can only happen when receiver close buffer channel
-		s.mu.Lock()
-		for i, receiver := range s.receivers {
-			if receiver == track {
-				s.receivers = append(s.receivers[:i], s.receivers[i+1:]...)
-				break
-			}
+	// remove current receiver from list
+	// it can only happen when receiver close buffer channel
+	s.mu.Lock()
+	for i, receiver := range s.receivers {
+		if receiver == track {
+			s.receivers = append(s.receivers[:i], s.receivers[i+1:]...)
+			break
 		}
-		s.mu.Unlock()
-	}()
+	}
+	s.mu.Unlock()
+}
+
+func (s *Sender) Start() {
+	s.mu.Lock()
+	for _, track := range s.receivers {
+		go s.worker(track)
+	}
+	s.mu.Unlock()
 }
 
 func (s *Sender) Close() {