title: Kurento media server recording is silent
body: <p>Basing on magic-mirror example I've tried to save result MP4 to file. Video is saved well, but audio is muted. </p>
  
  <p>How to enable audio stream in kurento?</p>
  
  <p><strong>UPDATE</strong>
  <em>Server code that creates endpoints and pipelines:</em></p>
  
  <pre><code> ...
   MediaPipeline pipeline = kurento.createMediaPipeline();
   ...
  
  String createWebRTCEndpoint(MediaPipeline pipeline, String uri, String exchange, String sdp) {
      RecorderEndpoint rep = new RecorderEndpoint.Builder(pipeline, uri)
          .stopOnEndOfStream()
          .withMediaProfile(MediaProfileSpecType.MP4)
          .build();
      WebRtcEndpoint webRtcEndpoint = new WebRtcEndpoint.Builder(pipeline)
          .build();
      webRtcEndpoint.connect(rep);
      rep.connect(webRtcEndpoint);
      rep.record();
      final String result = webRtcEndpoint.processOffer(sdp);
      synchronized (pipelinesAcc) {
          pipelines.put(exchange, new Tuple&lt;&gt;(pipeline, new Date()));
      }
      return result;
  }
  </code></pre>
  
  <p><em>SDP:</em></p>
  
  <pre><code>v=0
  o=Mozilla-SIPUA-35.0.1 15423 0 IN IP4 0.0.0.0
  s=SIP Call
  t=0 0
  a=ice-ufrag:358ccbc2
  a=ice-pwd:c40707c14349a6eb2b7fabb670c06c9c
  a=fingerprint:sha-256 B2:B5:89:8A:44:B9:BB:E6:EA:7A:AD:54:75:66:3C:B2:4A:89:CE:EA:22:81:BA:18:83:96:2D:A4:C3:87:E1:63
  m=audio 9 RTP/SAVPF 109 9 0 8 101
  c=IN IP4 0.0.0.0
  a=rtpmap:109 opus/48000/2
  a=ptime:20
  a=rtpmap:9 G722/8000
  a=rtpmap:0 PCMU/8000
  a=rtpmap:8 PCMA/8000
  a=rtpmap:101 telephone-event/8000
  a=fmtp:101 0-15
  a=sendrecv
  a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
  a=setup:actpass
  a=rtcp-mux
  a=candidate:0 1 UDP 2128609535 172.28.151.12 62452 typ host
  a=candidate:0 2 UDP 2128609534 172.28.151.12 62454 typ host
  a=candidate:2 1 UDP 1692467199 195.234.75.189 62452 typ srflx raddr 172.28.151.12 rport 62452
  a=candidate:2 2 UDP 1692467198 195.234.75.189 62454 typ srflx raddr 172.28.151.12 rport 62454
  m=video 9 RTP/SAVPF 120 126 97
  c=IN IP4 0.0.0.0
  a=rtpmap:120 VP8/90000
  a=rtpmap:126 H264/90000
  a=fmtp:126 profile-level-id=42e01f;packetization-mode=1
  a=rtpmap:97 H264/90000
  a=fmtp:97 profile-level-id=42e01f
  a=sendonly
  a=rtcp-fb:120 nack
  a=rtcp-fb:120 nack pli
  a=rtcp-fb:120 ccm fir
  a=rtcp-fb:126 nack
  a=rtcp-fb:126 nack pli
  a=rtcp-fb:126 ccm fir
  a=rtcp-fb:97 nack
  a=rtcp-fb:97 nack pli
  a=rtcp-fb:97 ccm fir
  a=setup:actpass
  a=rtcp-mux
  a=candidate:0 1 UDP 2128609535 172.28.151.12 51748 typ host
  a=candidate:0 2 UDP 2128609534 172.28.151.12 60009 typ host
  a=candidate:2 1 UDP 1692467199 195.234.75.189 51748 typ srflx raddr 172.28.151.12 rport 51748
  a=candidate:2 2 UDP 1692467198 195.234.75.189 60009 typ srflx raddr 172.28.151.12 rport 60009
  </code></pre>
  
  <p><strong>UPDATE-2</strong> </p>
  
  <pre><code>kurento-media-server -v
  Version: 5.0.4
  Found modules:
      Module: 'core' version '5.0.4'
      Module: 'elements' version '5.0.4'
      Module: 'filters' version '5.0.4'
  </code></pre>