WIP: simplify interface to TWCC 4/4

examples/bandwidth-estimation-from-disk/main.go

@@ -21,7 +21,7 @@
 	"github.com/pion/interceptor"
 	"github.com/pion/interceptor/pkg/cc"
 	"github.com/pion/interceptor/pkg/gcc"
 	"github.com/pion/webrtc/v4"
 	"github.com/pion/webrtc/v4/pkg/media"
 	"github.com/pion/webrtc/v4/pkg/media/ivfreader"
 )
@@ -59,45 +59,45 @@
 	}
 
 	i := &interceptor.Registry{}
 	m := &webrtc.MediaEngine{}
 	if err := m.RegisterDefaultCodecs(); err != nil {
 		panic(err)
 	}
 
-	// Create a Congestion Controller. This analyzes inbound and outbound data and provides
-	// suggestions on how much we should be sending.
-	//
-	// Passing `nil` means we use the default Estimation Algorithm which is Google Congestion Control.
-	// You can use the other ones that Pion provides, or write your own!
-	congestionController, err := cc.NewInterceptor(func() (cc.BandwidthEstimator, error) {
-		return gcc.NewSendSideBWE(gcc.SendSideBWEInitialBitrate(lowBitrate))
-	})
-	if err != nil {
+	if err := webrtc.ConfigureTWCCHeaderExtensionSender(m, i); err != nil {
 		panic(err)
 	}
 
-	estimatorChan := make(chan cc.BandwidthEstimator, 1)
-	congestionController.OnNewPeerConnection(func(id string, estimator cc.BandwidthEstimator) { //nolint: revive
-		estimatorChan <- estimator
-	})
-
-	i.Add(congestionController)
-	if err = webrtc.ConfigureTWCCHeaderExtensionSender(m, i); err != nil {
+	if err := webrtc.RegisterDefaultInterceptors(m, i); err != nil {
 		panic(err)
 	}
 
-	if err = webrtc.RegisterDefaultInterceptors(m, i); err != nil {
+	api := webrtc.NewAPI(
+		webrtc.WithInterceptorRegistry(i), webrtc.WithMediaEngine(m),
+	)
+
+	estimator, err := gcc.NewSendSideBWE(
+		gcc.SendSideBWEInitialBitrate(lowBitrate),
+	)
+	if err != nil {
 		panic(err)
 	}
-
-	// Create a new RTCPeerConnection
-	peerConnection, err := webrtc.NewAPI(webrtc.WithInterceptorRegistry(i), webrtc.WithMediaEngine(m)).NewPeerConnection(webrtc.Configuration{
+	interceptor, err := cc.NewSingleInterceptor(estimator)
+	if err != nil {
+		panic(err)
+	}
+	configuration := webrtc.Configuration{
 		ICEServers: []webrtc.ICEServer{
 			{
 				URLs: []string{"stun:stun.l.google.com:19302"},
 			},
 		},
-	})
+	}
+
+	peerConnection, err := api.NewPeerConnection(
+		configuration,
+		webrtc.WithInterceptor(interceptor),
+	)
 	if err != nil {
 		panic(err)
 	}
@@ -107,9 +107,6 @@
 		}
 	}()
 
-	// Wait until our Bandwidth Estimator has been created
-	estimator := <-estimatorChan
-
 	// Create a video track
 	videoTrack, err := webrtc.NewTrackLocalStaticSample(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeVP8}, "video", "pion")
 	if err != nil {
@@ -280,7 +277,7 @@
 }
 
 // JSON encode + base64 a SessionDescription
 func encode(obj *webrtc.SessionDescription) string {
 	b, err := json.Marshal(obj)
 	if err != nil {
 		panic(err)
@@ -290,7 +287,7 @@
 }
 
 // Decode a base64 and unmarshal JSON into a SessionDescription
 func decode(in string, obj *webrtc.SessionDescription) {
 	b, err := base64.StdEncoding.DecodeString(in)
 	if err != nil {
 		panic(err)

peerconnection.go

@@ -91,24 +91,26 @@
 	log logging.LeveledLogger
 
 	interceptorRTCPWriter interceptor.RTCPWriter
+
+	extraInterceptors []interceptor.Interceptor
 }
 
 // NewPeerConnection creates a PeerConnection with the default codecs and interceptors.
 //
 // If you wish to customize the set of available codecs and/or the set of active interceptors,
 // create an API with a custom MediaEngine and/or interceptor.Registry,
 // then call [(*API).NewPeerConnection] instead of this function.
-func NewPeerConnection(configuration Configuration) (*PeerConnection, error) {
+func NewPeerConnection(configuration Configuration, options... func (*PeerConnection) error) (*PeerConnection, error) {
 	api := NewAPI()
-	return api.NewPeerConnection(configuration)
+	return api.NewPeerConnection(configuration, options...)
 }
 
 // NewPeerConnection creates a new PeerConnection with the provided configuration against the received API object.
 // This method will attach a default set of codecs and interceptors to
 // the resulting PeerConnection.  If this behavior is not desired,
 // set the set of codecs and interceptors explicitly by using
 // [WithMediaEngine] and [WithInterceptorRegistry] when calling [NewAPI].
-func (api *API) NewPeerConnection(configuration Configuration) (*PeerConnection, error) {
+func (api *API) NewPeerConnection(configuration Configuration, options... func (*PeerConnection) error) (*PeerConnection, error) {
 	// https://w3c.github.io/webrtc-pc/#constructor (Step #2)
 	// Some variables defined explicitly despite their implicit zero values to
 	// allow better readability to understand what is happening.
@@ -136,12 +138,20 @@
 		api: api,
 		log: api.settingEngine.LoggerFactory.NewLogger("pc"),
 	}
+
+	for _, option := range options {
+		err := option(pc)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	pc.ops = newOperations(pc.updateNegotiationNeededFlagOnEmptyChain, pc.onNegotiationNeeded)
 
 	pc.iceConnectionState.Store(ICEConnectionStateNew)
 	pc.connectionState.Store(PeerConnectionStateNew)
 
-	i, err := api.interceptorRegistry.Build("")
+	i, err := api.interceptorRegistry.Build("", pc.extraInterceptors...)
 	if err != nil {
 		return nil, err
 	}
@@ -195,6 +205,13 @@
 	return pc, nil
 }
 
+func WithInterceptor(i interceptor.Interceptor) func (*PeerConnection) error {
+	return func(pc *PeerConnection) error {
+		pc.extraInterceptors = append(pc.extraInterceptors, i)
+		return nil
+	}
+}
+
 // initConfiguration defines validation of the specified Configuration and
 // its assignment to the internal configuration variable. This function differs
 // from its SetConfiguration counterpart because most of the checks do not