Replace RTCPFeedback in down tracks.

We used to copy the RTCPFeeback field from the up track.  It is
more correct to regenerate it with the exact feedback types
that we expect.

rtpconn/webclient.go

@@ -9,6 +9,7 @@ import (
 	"log"
 	"net"
 	"os"
+	"strings"
 	"sync"
 	"time"
 
@@ -381,8 +382,16 @@ func addDownTrackUnlocked(conn *rtpDownConnection, remoteTrack *rtpUpTrack) erro
 		msid = "dummy"
 	}
 
+	// replace the RTCP feedback types with the ones we understand
+	remoteCodec := remoteTrack.Codec()
+	if strings.HasPrefix(strings.ToLower(remoteCodec.MimeType), "video/") {
+		remoteCodec.RTCPFeedback = group.VideoRTCPFeedback
+	} else {
+		remoteCodec.RTCPFeedback = group.AudioRTCPFeedback
+	}
+
 	local, err := webrtc.NewTrackLocalStaticRTP(
-		remoteTrack.Codec(), id, msid,
+		remoteCodec, id, msid,
 	)
 	if err != nil {
 		return err
@@ -1660,7 +1669,7 @@ func handleClientMessage(c *webClient, m clientMessage) error {
 			m := clientMessage{
 				Type:       "usermessage",
 				Kind:       "clearchat",
-				Value:       m.Value,
+				Value:      m.Value,
 				Privileged: true,
 			}
 			err := broadcast(g.GetClients(nil), m)