Bolting on send side simulcast

Introduces AddEncoding method in RTP sender to add simulcast encodings.

Added UTs for AddEncoding.
Also modified the Simulcast send test to use the new API.

errors.go

@@ -142,6 +142,9 @@ var (
 	// ErrRTPSenderNewTrackHasIncorrectKind indicates that the new track is of a different kind than the previous/original
 	ErrRTPSenderNewTrackHasIncorrectKind = errors.New("new track must be of the same kind as previous")
 
+	// ErrRTPSenderNewTrackHasIncorrectEnvelope indicates that the new track has a different envelope than the previous/original
+	ErrRTPSenderNewTrackHasIncorrectEnvelope = errors.New("new track must have the same envelope as previous")
+
 	// ErrUnbindFailed indicates that a TrackLocal was not able to be unbind
 	ErrUnbindFailed = errors.New("failed to unbind TrackLocal from PeerConnection")
 
@@ -202,10 +205,16 @@ var (
 	errRTPReceiverWithSSRCTrackStreamNotFound = errors.New("unable to find stream for Track with SSRC")
 	errRTPReceiverForRIDTrackStreamNotFound   = errors.New("no trackStreams found for RID")
 
-	errRTPSenderTrackNil          = errors.New("Track must not be nil")
-	errRTPSenderDTLSTransportNil  = errors.New("DTLSTransport must not be nil")
-	errRTPSenderSendAlreadyCalled = errors.New("Send has already been called")
-	errRTPSenderTrackRemoved      = errors.New("Sender Track has been removed or replaced to nil")
+	errRTPSenderTrackNil             = errors.New("Track must not be nil")
+	errRTPSenderDTLSTransportNil     = errors.New("DTLSTransport must not be nil")
+	errRTPSenderSendAlreadyCalled    = errors.New("Send has already been called")
+	errRTPSenderStopped              = errors.New("Sender has already been stopped")
+	errRTPSenderTrackRemoved         = errors.New("Sender Track has been removed or replaced to nil")
+	errRTPSenderRidNil               = errors.New("Sender cannot add encoding as rid is empty")
+	errRTPSenderNoBaseEncoding       = errors.New("Sender cannot add encoding as there is no base track")
+	errRTPSenderBaseEncodingMismatch = errors.New("Sender cannot add encoding as provided track does not match base track")
+	errRTPSenderRIDCollision         = errors.New("Sender cannot encoding due to RID collision")
+	errRTPSenderNoTrackForRID        = errors.New("Sender does not have track for RID")
 
 	errRTPTransceiverCannotChangeMid        = errors.New("errRTPSenderTrackNil")
 	errRTPTransceiverSetSendingInvalidState = errors.New("invalid state change in RTPTransceiver.setSending")

peerconnection_media_test.go

@@ -162,7 +162,7 @@ func TestPeerConnection_Media_Sample(t *testing.T) {
 	go func() {
 		for {
 			time.Sleep(time.Millisecond * 100)
-			if routineErr := pcOffer.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{SenderSSRC: uint32(sender.ssrc), MediaSSRC: uint32(sender.ssrc)}}); routineErr != nil {
+			if routineErr := pcOffer.WriteRTCP([]rtcp.Packet{&rtcp.PictureLossIndication{SenderSSRC: uint32(sender.trackEncodings[0].ssrc), MediaSSRC: uint32(sender.trackEncodings[0].ssrc)}}); routineErr != nil {
 				awaitRTCPSenderSend <- routineErr
 			}
 
@@ -643,12 +643,12 @@ func TestAddTransceiverAddTrack_Reuse(t *testing.T) {
 	track1, sender1 := addTrack()
 	assert.Equal(t, 1, len(pc.GetTransceivers()))
 	assert.Equal(t, sender1, tr.Sender())
-	assert.Equal(t, track1, tr.Sender().track)
+	assert.Equal(t, track1, tr.Sender().Track())
 	require.NoError(t, pc.RemoveTrack(sender1))
 
 	track2, _ := addTrack()
 	assert.Equal(t, 1, len(pc.GetTransceivers()))
-	assert.Equal(t, track2, tr.Sender().track)
+	assert.Equal(t, track2, tr.Sender().Track())
 
 	addTrack()
 	assert.Equal(t, 2, len(pc.GetTransceivers()))
@@ -1256,23 +1256,47 @@ func TestPeerConnection_Simulcast(t *testing.T) {
 		pcOffer, pcAnswer, err := NewAPI(WithMediaEngine(m)).newPair(Configuration{})
 		assert.NoError(t, err)
 
-		vp8Writer, err := NewTrackLocalStaticRTP(RTPCodecCapability{MimeType: MimeTypeVP8}, "video", "pion2")
+		vp8WriterA, err := NewTrackLocalStaticRTP(RTPCodecCapability{MimeType: MimeTypeVP8}, "video", "pion2", WithRTPStreamID("a"))
 		assert.NoError(t, err)
 
-		_, err = pcOffer.AddTrack(vp8Writer)
+		sender, err := pcOffer.AddTrack(vp8WriterA)
+		assert.NoError(t, err)
+		assert.NotNil(t, sender)
+
+		vp8WriterB, err := NewTrackLocalStaticRTP(RTPCodecCapability{MimeType: MimeTypeVP8}, "video", "pion2", WithRTPStreamID("b"))
+		assert.NoError(t, err)
+		err = sender.AddEncoding(vp8WriterB)
+		assert.NoError(t, err)
+
+		vp8WriterC, err := NewTrackLocalStaticRTP(RTPCodecCapability{MimeType: MimeTypeVP8}, "video", "pion2", WithRTPStreamID("c"))
+		assert.NoError(t, err)
+		err = sender.AddEncoding(vp8WriterC)
 		assert.NoError(t, err)
 
 		ridMap = map[string]int{}
 		pcAnswer.OnTrack(onTrackHandler)
 
-		assert.NoError(t, signalPairWithModification(pcOffer, pcAnswer, func(sessionDescription string) string {
-			sessionDescription = strings.Split(sessionDescription, "a=end-of-candidates\r\n")[0]
-			sessionDescription = filterSsrc(sessionDescription)
-			for _, rid := range rids {
-				sessionDescription += "a=" + sdpAttributeRid + ":" + rid + " send\r\n"
+		parameters := sender.GetParameters()
+		assert.Equal(t, "a", parameters.Encodings[0].RID)
+		assert.Equal(t, "b", parameters.Encodings[1].RID)
+		assert.Equal(t, "c", parameters.Encodings[2].RID)
+
+		var midID, ridID, rsidID uint8
+		for _, extension := range parameters.HeaderExtensions {
+			switch extension.URI {
+			case sdp.SDESMidURI:
+				midID = uint8(extension.ID)
+			case sdp.SDESRTPStreamIDURI:
+				ridID = uint8(extension.ID)
+			case sdesRepairRTPStreamIDURI:
+				rsidID = uint8(extension.ID)
 			}
-			return sessionDescription + "a=simulcast:send " + strings.Join(rids, ";") + "\r\n"
-		}))
+		}
+		assert.NotZero(t, midID)
+		assert.NotZero(t, ridID)
+		assert.NotZero(t, rsidID)
+
+		assert.NoError(t, signalPair(pcOffer, pcAnswer))
 
 		for sequenceNumber := uint16(0); !ridsFullfilled(); sequenceNumber++ {
 			time.Sleep(20 * time.Millisecond)
@@ -1284,17 +1308,26 @@ func TestPeerConnection_Simulcast(t *testing.T) {
 					SequenceNumber: sequenceNumber,
 					PayloadType:    96,
 				}
-				assert.NoError(t, header.SetExtension(1, []byte("0")))
+				assert.NoError(t, header.SetExtension(midID, []byte("0")))
 
 				// Send RSID for first 10 packets
 				if sequenceNumber >= 10 {
-					assert.NoError(t, header.SetExtension(2, []byte(rid)))
+					assert.NoError(t, header.SetExtension(ridID, []byte(rid)))
 				} else {
-					assert.NoError(t, header.SetExtension(3, []byte(rid)))
+					assert.NoError(t, header.SetExtension(rsidID, []byte(rid)))
 					header.SSRC += 10
 				}
 
-				_, err := vp8Writer.bindings[0].writeStream.WriteRTP(header, []byte{0x00})
+				var writer *TrackLocalStaticRTP
+				switch rid {
+				case "a":
+					writer = vp8WriterA
+				case "b":
+					writer = vp8WriterB
+				case "c":
+					writer = vp8WriterC
+				}
+				_, err = writer.bindings[0].writeStream.WriteRTP(header, []byte{0x00})
 				assert.NoError(t, err)
 			}
 		}

peerconnection_renegotiation_test.go

@@ -371,7 +371,7 @@ func TestPeerConnection_Transceiver_Mid(t *testing.T) {
 	// Must have 3 media descriptions (2 video channels)
 	assert.Equal(t, len(offer.parsed.MediaDescriptions), 2)
 
-	assert.True(t, sdpMidHasSsrc(offer, "0", sender1.ssrc), "Expected mid %q with ssrc %d, offer.SDP: %s", "0", sender1.ssrc, offer.SDP)
+	assert.True(t, sdpMidHasSsrc(offer, "0", sender1.trackEncodings[0].ssrc), "Expected mid %q with ssrc %d, offer.SDP: %s", "0", sender1.trackEncodings[0].ssrc, offer.SDP)
 
 	// Remove first track, must keep same number of media
 	// descriptions and same track ssrc for mid 1 as previous
@@ -382,7 +382,7 @@ func TestPeerConnection_Transceiver_Mid(t *testing.T) {
 
 	assert.Equal(t, len(offer.parsed.MediaDescriptions), 2)
 
-	assert.True(t, sdpMidHasSsrc(offer, "1", sender2.ssrc), "Expected mid %q with ssrc %d, offer.SDP: %s", "1", sender2.ssrc, offer.SDP)
+	assert.True(t, sdpMidHasSsrc(offer, "1", sender2.trackEncodings[0].ssrc), "Expected mid %q with ssrc %d, offer.SDP: %s", "1", sender2.trackEncodings[0].ssrc, offer.SDP)
 
 	_, err = pcAnswer.CreateAnswer(nil)
 	assert.Equal(t, err, &rtcerr.InvalidStateError{Err: ErrIncorrectSignalingState})
@@ -402,8 +402,8 @@ func TestPeerConnection_Transceiver_Mid(t *testing.T) {
 	// We reuse the existing non-sending transceiver
 	assert.Equal(t, len(offer.parsed.MediaDescriptions), 2)
 
-	assert.True(t, sdpMidHasSsrc(offer, "0", sender3.ssrc), "Expected mid %q with ssrc %d, offer.sdp: %s", "0", sender3.ssrc, offer.SDP)
-	assert.True(t, sdpMidHasSsrc(offer, "1", sender2.ssrc), "Expected mid %q with ssrc %d, offer.sdp: %s", "1", sender2.ssrc, offer.SDP)
+	assert.True(t, sdpMidHasSsrc(offer, "0", sender3.trackEncodings[0].ssrc), "Expected mid %q with ssrc %d, offer.sdp: %s", "0", sender3.trackEncodings[0].ssrc, offer.SDP)
+	assert.True(t, sdpMidHasSsrc(offer, "1", sender2.trackEncodings[0].ssrc), "Expected mid %q with ssrc %d, offer.sdp: %s", "1", sender2.trackEncodings[0].ssrc, offer.SDP)
 
 	closePairNow(t, pcOffer, pcAnswer)
 }