Fix receiveForRtx usage for simulcast

peerconnection.go

@@ -1622,7 +1622,7 @@ func (pc *PeerConnection) handleIncomingSSRC(rtpStream io.Reader, ssrc SSRC) err
 			if rsid != "" {
 				receiver.mu.Lock()
 				defer receiver.mu.Unlock()
-				return receiver.receiveForRtx(SSRC(0), rsid, streamInfo, readStream, interceptor, rtcpReadStream, rtcpInterceptor)
+				return receiver.receiveForSimulcastRtx(rsid, streamInfo, readStream, interceptor, rtcpReadStream, rtcpInterceptor)
 			}
 
 			track, err := receiver.receiveForRid(rid, params, streamInfo, readStream, interceptor, rtcpReadStream, rtcpInterceptor)

rtpreceiver.go

@@ -225,7 +225,7 @@ func (r *RTPReceiver) startReceive(parameters RTPReceiveParameters) error {
 				return err
 			}
 
-			if err = r.receiveForRtx(rtxSsrc, "", streamInfo, rtpReadStream, rtpInterceptor, rtcpReadStream, rtcpInterceptor); err != nil {
+			if err = r.receiveForRtx(rtxSsrc, streamInfo, rtpReadStream, rtpInterceptor, rtcpReadStream, rtcpInterceptor); err != nil {
 				return err
 			}
 		}
@@ -409,21 +409,44 @@ func (r *RTPReceiver) receiveForRid(rid string, params RTPParameters, streamInfo
 	return nil, fmt.Errorf("%w: %s", errRTPReceiverForRIDTrackStreamNotFound, rid)
 }
 
+func (r *RTPReceiver) receiveForSimulcastRtx(rsid string, streamInfo *interceptor.StreamInfo, rtpReadStream *srtp.ReadStreamSRTP, rtpInterceptor interceptor.RTPReader, rtcpReadStream *srtp.ReadStreamSRTCP, rtcpInterceptor interceptor.RTCPReader) error {
+	var track *trackStreams
+	for i := range r.tracks {
+		if r.tracks[i].track.RID() == rsid {
+			track = &r.tracks[i]
+		}
+	}
+
+	if track == nil {
+		return fmt.Errorf("%w: rsid(%s)", errRTPReceiverForRIDTrackStreamNotFound, rsid)
+	}
+
+	track.repairStreamInfo = streamInfo
+	track.repairReadStream = rtpReadStream
+	track.repairInterceptor = rtpInterceptor
+	track.repairRtcpReadStream = rtcpReadStream
+	track.repairRtcpInterceptor = rtcpInterceptor
+
+	go func() {
+		b := make([]byte, r.api.settingEngine.getReceiveMTU())
+		for {
+			if _, _, readErr := track.repairInterceptor.Read(b, nil); readErr != nil {
+				return
+			}
+		}
+	}()
+	return nil
+}
+
 // receiveForRtx starts a routine that processes the repair stream
-func (r *RTPReceiver) receiveForRtx(ssrc SSRC, rsid string, streamInfo *interceptor.StreamInfo, rtpReadStream *srtp.ReadStreamSRTP, rtpInterceptor interceptor.RTPReader, rtcpReadStream *srtp.ReadStreamSRTCP, rtcpInterceptor interceptor.RTCPReader) error {
+func (r *RTPReceiver) receiveForRtx(ssrc SSRC, streamInfo *interceptor.StreamInfo, rtpReadStream *srtp.ReadStreamSRTP, rtpInterceptor interceptor.RTPReader, rtcpReadStream *srtp.ReadStreamSRTCP, rtcpInterceptor interceptor.RTCPReader) error {
 	var track *trackStreams
 	if ssrc != 0 && len(r.tracks) == 1 {
 		track = &r.tracks[0]
-	} else {
-		for i := range r.tracks {
-			if r.tracks[i].track.RID() == rsid {
-				track = &r.tracks[i]
-			}
-		}
 	}
 
 	if track == nil {
-		return fmt.Errorf("%w: ssrc(%d) rsid(%s)", errRTPReceiverForRIDTrackStreamNotFound, ssrc, rsid)
+		return fmt.Errorf("%w: ssrc(%d)", errRTPReceiverForRIDTrackStreamNotFound, ssrc)
 	}
 
 	track.repairStreamInfo = streamInfo