Feat/switch codec

go.mod

@@ -1,6 +1,10 @@
 module github.com/pion/webrtc/v4
 
-go 1.20
+go 1.22.0
+
+toolchain go1.22.6
+
+replace github.com/pion/rtp => github.com/aginetwork7/rtp v1.0.0-alpha.0
 
 require (
 	github.com/pion/datachannel v1.5.10
@@ -25,7 +29,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/onsi/ginkgo v1.16.5 // indirect
-	github.com/onsi/gomega v1.17.0 // indirect
+	github.com/onsi/gomega v1.36.2 // indirect
 	github.com/pion/mdns/v2 v2.0.7 // indirect
 	github.com/pion/turn/v4 v4.0.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/aginetwork7/rtp v1.0.0-alpha.0 h1:XNJlS5Ccb320r0vKOlVKiYqIEyKLlVBV1KW+VbY/+TI=
+github.com/aginetwork7/rtp v1.0.0-alpha.0/go.mod h1:8uMBJj32Pa1wwx8Fuv/AsFhn8jsgw+3rUC2PfoBZ8p4=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -12,29 +14,29 @@ github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrU
 github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
-github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
 github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=
 github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.12.1/go.mod h1:zj2OWP4+oCPe1qIXoGWkgMRwljMUYCdkwsT2108oapk=
-github.com/onsi/ginkgo v1.16.4/go.mod h1:dX+/inL/fNMqNlz0e9LfyB9TswhZpCVdJM/Z6Vvnwo0=
 github.com/onsi/ginkgo v1.16.5 h1:8xi0RTUf59SOSfEtZMvwTvXYMzG4gV23XVHOZiXNtnE=
 github.com/onsi/ginkgo v1.16.5/go.mod h1:+E8gABHa3K6zRBolWtd+ROzc/U5bkGt0FwiG042wbpU=
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
-github.com/onsi/gomega v1.17.0 h1:9Luw4uT5HTjHTN8+aNcSThgH1vdXnmdJ8xIfZ4wyTRE=
-github.com/onsi/gomega v1.17.0/go.mod h1:HnhC7FXeEQY45zxNK3PPoIUhzk/80Xly9PcubAlGdZY=
+github.com/onsi/gomega v1.36.2 h1:koNYke6TVk6ZmnyHrCXba/T/MoLBXFjeC1PtvYgw0A8=
+github.com/onsi/gomega v1.36.2/go.mod h1:DdwyADRjrc825LhMEkD76cHR5+pUnjhUN8GlHlRPHzY=
 github.com/pion/datachannel v1.5.10 h1:ly0Q26K1i6ZkGf42W7D4hQYR90pZwzFOjTq5AuCKk4o=
 github.com/pion/datachannel v1.5.10/go.mod h1:p/jJfC9arb29W7WrxyKbepTU20CFgyx5oLo8Rs4Py/M=
 github.com/pion/dtls/v3 v3.0.4 h1:44CZekewMzfrn9pmGrj5BNnTMDCFwr+6sLH+cCuLM7U=
@@ -51,8 +53,6 @@ github.com/pion/randutil v0.1.0 h1:CFG1UdESneORglEsnimhUjf33Rwjubwj6xfiOXBa3mA=
 github.com/pion/randutil v0.1.0/go.mod h1:XcJrSMMbbMRhASFVOlj/5hQial/Y8oH/HVo7TBZq+j8=
 github.com/pion/rtcp v1.2.15 h1:LZQi2JbdipLOj4eBjK4wlVoQWfrZbh3Q6eHtWtJBZBo=
 github.com/pion/rtcp v1.2.15/go.mod h1:jlGuAjHMEXwMUHK78RgX0UmEJFV4zUKOFHR7OP+D3D0=
-github.com/pion/rtp v1.8.13 h1:8uSUPpjSL4OlwZI8Ygqu7+h2p9NPFB+yAZ461Xn5sNg=
-github.com/pion/rtp v1.8.13/go.mod h1:8uMBJj32Pa1wwx8Fuv/AsFhn8jsgw+3rUC2PfoBZ8p4=
 github.com/pion/sctp v1.8.37 h1:ZDmGPtRPX9mKCiVXtMbTWybFw3z/hVKAZgU81wcOrqs=
 github.com/pion/sctp v1.8.37/go.mod h1:cNiLdchXra8fHQwmIoqw0MbLLMs+f7uQ+dGMG2gWebE=
 github.com/pion/sdp/v3 v3.0.11 h1:VhgVSopdsBKwhCFoyyPmT1fKMeV9nLMrEKxNOdy3IVI=
@@ -87,7 +87,6 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.0.0-20210428140749-89ef3d95e781/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
 golang.org/x/net v0.35.0 h1:T5GQRQb2y08kTAByq9L4/bz8cipCdA8FbRTXewonqY8=
 golang.org/x/net v0.35.0/go.mod h1:EglIi67kWsHKlRzzVMUD93VMSWGFOMSZgxFjparz1Qk=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -101,16 +100,13 @@ golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210112080510-489259a85091/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
 golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
+golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20201224043029-2b0845dc783e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
@@ -124,17 +120,14 @@ google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQ
 google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
-google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
-gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

peerconnection.go

@@ -1042,14 +1042,18 @@ func (pc *PeerConnection) SetLocalDescription(desc SessionDescription) error {
 	weAnswer := desc.Type == SDPTypeAnswer
 	remoteDesc := pc.RemoteDescription()
 	if weAnswer && remoteDesc != nil {
-		_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, false)
+		rejectedMids := []string{}
+		_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, false, &rejectedMids)
 		if err := pc.startRTPSenders(currentTransceivers); err != nil {
 			return err
 		}
 		pc.configureRTPReceivers(haveLocalDescription, remoteDesc, currentTransceivers)
 		pc.ops.Enqueue(func() {
 			pc.startRTP(haveLocalDescription, remoteDesc, currentTransceivers)
 		})
+		pc.mu.Lock()
+		pc.removeRTPTransceiver(rejectedMids)
+		pc.mu.Unlock()
 	}
 
 	mediaSection, ok := selectCandidateMediaSection(desc.parsed)
@@ -1226,14 +1230,18 @@ func (pc *PeerConnection) SetRemoteDescription(desc SessionDescription) error {
 
 	if isRenegotiation {
 		if weOffer {
-			_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, true)
+			rejected := []string{}
+			_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, true, &rejected)
 			if err = pc.startRTPSenders(currentTransceivers); err != nil {
 				return err
 			}
 			pc.configureRTPReceivers(true, &desc, currentTransceivers)
 			pc.ops.Enqueue(func() {
 				pc.startRTP(true, &desc, currentTransceivers)
 			})
+			pc.mu.Lock()
+			pc.removeRTPTransceiver(rejected)
+			pc.mu.Unlock()
 		}
 
 		return nil
@@ -1258,7 +1266,7 @@ func (pc *PeerConnection) SetRemoteDescription(desc SessionDescription) error {
 	// Start the networking in a new routine since it will block until
 	// the connection is actually established.
 	if weOffer {
-		_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, true)
+		_ = setRTPTransceiverCurrentDirection(&desc, currentTransceivers, true, nil)
 		if err := pc.startRTPSenders(currentTransceivers); err != nil {
 			return err
 		}
@@ -1333,12 +1341,8 @@ func (pc *PeerConnection) startReceiver(incoming trackDetails, receiver *RTPRece
 	}
 }
 
-//nolint:cyclop
-func setRTPTransceiverCurrentDirection(
-	answer *SessionDescription,
-	currentTransceivers []*RTPTransceiver,
-	weOffer bool,
-) error {
+// rejected is only meaningful when SessionDescription is answer
+func setRTPTransceiverCurrentDirection(answer *SessionDescription, currentTransceivers []*RTPTransceiver, weOffer bool, rejectedMids *[]string) error {
 	currentTransceivers = append([]*RTPTransceiver{}, currentTransceivers...)
 	for _, media := range answer.parsed.MediaDescriptions {
 		midValue := getMidValue(media)
@@ -1379,7 +1383,10 @@ func setRTPTransceiverCurrentDirection(
 		if !weOffer && direction == RTPTransceiverDirectionSendonly && transceiver.Sender() == nil {
 			direction = RTPTransceiverDirectionInactive
 		}
-
+		// reject transceiver if it is inactive
+		if rejectedMids != nil && media.MediaName.Port.Value == 0 && direction == RTPTransceiverDirectionInactive {
+			*rejectedMids = append(*rejectedMids, midValue)
+		}
 		transceiver.setCurrentDirection(direction)
 	}
 
@@ -2419,6 +2426,38 @@ func (pc *PeerConnection) addRTPTransceiver(t *RTPTransceiver) {
 	pc.onNegotiationNeeded()
 }
 
+// removeRTPTransceiver remove inactive
+// and fires onNegotiationNeeded;
+// caller of this method should hold `pc.mu` lock
+func (pc *PeerConnection) removeRTPTransceiver(mids []string) {
+	if len(mids) == 0 {
+		return
+	}
+
+	midSet := make(map[string]struct{}, len(mids))
+	for _, mid := range mids {
+		if mid == "" {
+			continue
+		}
+		midSet[mid] = struct{}{}
+	}
+
+	n := 0
+	for _, transceiver := range pc.rtpTransceivers {
+		if _, exists := midSet[transceiver.Mid()]; exists {
+			err := transceiver.Stop()
+			if err != nil {
+				pc.log.Errorf("Failed to stop transceiver: %s", err)
+			}
+		} else {
+			pc.rtpTransceivers[n] = transceiver
+			n++
+		}
+	}
+	// Resize the slice to remove unwanted transceivers
+	pc.rtpTransceivers = pc.rtpTransceivers[:n]
+}
+
 // CurrentLocalDescription represents the local description that was
 // successfully negotiated the last time the PeerConnection transitioned
 // into the stable state plus any local candidates that have been generated
@@ -2830,10 +2869,16 @@ func (pc *PeerConnection) generateMatchedSDP(
 			mediaTransceivers := []*RTPTransceiver{transceiver}
 
 			extensions, _ := rtpExtensionsFromMediaDescription(media)
-			mediaSections = append(
-				mediaSections,
-				mediaSection{id: midValue, transceivers: mediaTransceivers, matchExtensions: extensions, rids: getRids(media)},
-			)
+			rejected := false
+			if media.MediaName.Port.Value == 0 {
+				for _, attr := range media.Attributes {
+					if attr.Key == sdp.AttrKeyInactive {
+						rejected = true
+						break
+					}
+				}
+			}
+			mediaSections = append(mediaSections, mediaSection{id: midValue, transceivers: mediaTransceivers, matchExtensions: extensions, rids: getRids(media), rejected: rejected})
 		}
 	}
 

peerconnection_test.go

@@ -753,6 +753,51 @@ func TestAddTransceiver(t *testing.T) {
 }
 
 // Assert that SCTPTransport -> DTLSTransport -> ICETransport works after connected.
+func TestRemoveMiddleTransceiverAndRenegotiate(t *testing.T) {
+	// Initialize the offerPC PeerConnection
+	offerPC, err := NewPeerConnection(Configuration{})
+	assert.NoError(t, err)
+	defer offerPC.Close()
+
+	// Initialize the answerPC PeerConnection
+	answerPC, err := NewPeerConnection(Configuration{})
+	assert.NoError(t, err)
+	defer answerPC.Close()
+
+	// Add multiple transceivers to the offerer
+	videoTransceiver1, err := offerPC.AddTransceiverFromKind(RTPCodecTypeVideo)
+	assert.NoError(t, err)
+	audioTransceiver, err := offerPC.AddTransceiverFromKind(RTPCodecTypeAudio)
+	assert.NoError(t, err)
+	videoTransceiver2, err := offerPC.AddTransceiverFromKind(RTPCodecTypeVideo)
+	assert.NoError(t, err)
+
+	// Perform initial SDP negotiation
+	offer, err := offerPC.CreateOffer(nil)
+	assert.NoError(t, err)
+	assert.NoError(t, offerPC.SetLocalDescription(offer))
+	assert.NoError(t, answerPC.SetRemoteDescription(*offerPC.LocalDescription()))
+	answer, err := answerPC.CreateAnswer(nil)
+	assert.NoError(t, err)
+	assert.NoError(t, answerPC.SetLocalDescription(answer))
+	assert.NoError(t, offerPC.SetRemoteDescription(*answerPC.LocalDescription()))
+
+	// Ensure MIDs are assigned
+	assert.NotEmpty(t, videoTransceiver1.Mid())
+	assert.NotEmpty(t, audioTransceiver.Mid())
+	assert.NotEmpty(t, videoTransceiver2.Mid())
+
+	// Remove the middle transceiver (audio) using its MID
+	offerPC.removeRTPTransceiver([]string{audioTransceiver.Mid()})
+
+	// Verify the transceiver was removed
+	remainingTransceivers := offerPC.GetTransceivers()
+	assert.Len(t, remainingTransceivers, 2)
+	assert.Equal(t, videoTransceiver1.Mid(), remainingTransceivers[0].Mid())
+	assert.Equal(t, videoTransceiver2.Mid(), remainingTransceivers[1].Mid())
+}
+
+// Assert that SCTPTransport -> DTLSTransport -> ICETransport works after connected
 func TestTransportChain(t *testing.T) {
 	offer, answer, err := newPair()
 	assert.NoError(t, err)

sdp.go

@@ -519,10 +519,12 @@ func addTransceiverSDP(
 			media.WithValueAttribute("rtcp-fb", fmt.Sprintf("%d %s %s", codec.PayloadType, feedback.Type, feedback.Parameter))
 		}
 	}
-	if len(codecs) == 0 {
+	if len(codecs) == 0 || mediaSection.rejected {
 		// If we are sender and we have no codecs throw an error early
 		if transceiver.Sender() != nil {
-			return false, ErrSenderWithNoCodecs
+			if !mediaSection.rejected {
+				return false, ErrSenderWithNoCodecs
+			}
 		}
 
 		// Explicitly reject track if we don't have the codec
@@ -546,9 +548,14 @@ func addTransceiverSDP(
 					Address: "0.0.0.0",
 				},
 			},
+			Attributes: []sdp.Attribute{
+				{Key: RTPTransceiverDirectionInactive.String(), Value: ""},
+				{Key: "mid", Value: midValue},
+			},
 		})
 
 		return false, nil
+
 	}
 
 	directions := []RTPTransceiverDirection{}
@@ -619,6 +626,7 @@ type mediaSection struct {
 	data            bool
 	matchExtensions map[string]int
 	rids            []*simulcastRid
+	rejected        bool
 }
 
 func bundleMatchFromRemote(matchBundleGroup *string) func(mid string) bool {