Fix nil rtcpInterceptor on track.Bind

Create rtcpInterceptor before bind called.

rtpsender.go

@@ -311,6 +311,12 @@ func (r *RTPSender) Send(parameters RTPSendParameters) error {
 		trackEncoding.ssrc = parameters.Encodings[idx].SSRC
 		trackEncoding.ssrcRTX = parameters.Encodings[idx].RTX.SSRC
 		trackEncoding.ssrcFEC = parameters.Encodings[idx].FEC.SSRC
+		trackEncoding.rtcpInterceptor = r.api.interceptor.BindRTCPReader(
+			interceptor.RTCPReaderFunc(func(in []byte, a interceptor.Attributes) (n int, attributes interceptor.Attributes, err error) {
+				n, err = trackEncoding.srtpStream.Read(in)
+				return n, a, err
+			}),
+		)
 		trackEncoding.context = &baseTrackLocalContext{
 			id:              r.id,
 			params:          rtpParameters,
@@ -339,13 +345,6 @@ func (r *RTPSender) Send(parameters RTPSendParameters) error {
 			parameters.HeaderExtensions,
 		)
 
-		trackEncoding.rtcpInterceptor = r.api.interceptor.BindRTCPReader(
-			interceptor.RTCPReaderFunc(func(in []byte, a interceptor.Attributes) (n int, attributes interceptor.Attributes, err error) {
-				n, err = trackEncoding.srtpStream.Read(in)
-				return n, a, err
-			}),
-		)
-
 		rtpInterceptor := r.api.interceptor.BindLocalStream(
 			&trackEncoding.streamInfo,
 			interceptor.RTPWriterFunc(func(header *rtp.Header, payload []byte, _ interceptor.Attributes) (int, error) {

rtpsender_test.go

@@ -484,3 +484,40 @@ func Test_RTPSender_RTX_Support(t *testing.T) {
 		assert.NoError(t, peerConnection.Close())
 	})
 }
+
+func Test_RTPSender_RTCPReader_Bind_Not_Nil(t *testing.T) {
+	track, err := NewTrackLocalStaticSample(RTPCodecCapability{MimeType: MimeTypeVP8}, "video", "pion")
+	assert.NoError(t, err)
+
+	peerConnection, err := NewPeerConnection(Configuration{})
+	assert.NoError(t, err)
+
+	bindCalled := make(chan struct{})
+	rtpSender, err := peerConnection.AddTrack(&TrackLocalCheckRTCPReaderOnBind{
+		t:                      t,
+		TrackLocalStaticSample: track,
+		bindCalled:             bindCalled,
+	})
+	assert.NoError(t, err)
+
+	parameter := rtpSender.GetParameters()
+	err = rtpSender.Send(parameter)
+	<-rtpSender.sendCalled
+	<-bindCalled
+	assert.NoError(t, err)
+
+	assert.NoError(t, peerConnection.Close())
+}
+
+type TrackLocalCheckRTCPReaderOnBind struct {
+	*TrackLocalStaticSample
+	t          *testing.T
+	bindCalled chan struct{}
+}
+
+func (s *TrackLocalCheckRTCPReaderOnBind) Bind(ctx TrackLocalContext) (RTPCodecParameters, error) {
+	assert.NotNil(s.t, ctx.RTCPReader())
+	p, err := s.TrackLocalStaticSample.Bind(ctx)
+	close(s.bindCalled)
+	return p, err
+}