Fix backchannel reconnection issue

cmd/rtsp/rtsp.go

@@ -84,10 +84,10 @@ func rtspHandler(url string) (streamer.Producer, error) {
 		}
 
 		// second try without backchannel, we need to reconnect
+		conn.Backchannel = false
 		if err = conn.Dial(); err != nil {
 			return nil, err
 		}
-		conn.Backchannel = false
 		if err = conn.Describe(); err != nil {
 			return nil, err
 		}

cmd/streams/producer.go

@@ -64,6 +64,9 @@ func (p *Producer) GetTrack(media *streamer.Media, codec *streamer.Codec) *strea
 	}
 
 	track := p.element.GetTrack(media, codec)
+	if track == nil {
+		return nil
+	}
 
 	for _, t := range p.tracks {
 		if track == t {