code: function writeRejectedMediaSection(transceiver) {
    var sdp = '';
    if (transceiver.kind === 'application') {
      if (transceiver.protocol === 'DTLS/SCTP') { // legacy fmt
        sdp += 'm=application 0 DTLS/SCTP 5000\r\n';
      } else {
        sdp += 'm=application 0 ' + transceiver.protocol +
          ' webrtc-datachannel\r\n';
      }
    } else if (transceiver.kind === 'audio') {
      sdp += 'm=audio 0 UDP/TLS/RTP/SAVPF 0\r\n' +
        'a=rtpmap:0 PCMU/8000\r\n';
    } else if (transceiver.kind === 'video') {
      sdp += 'm=video 0 UDP/TLS/RTP/SAVPF 120\r\n' +
        'a=rtpmap:120 VP8/90000\r\n';
    }
    sdp += 'c=IN IP4 0.0.0.0\r\n' +
      'a=inactive\r\n' +
      'a=mid:' + transceiver.mid + '\r\n';
    return sdp;
  }
docs: /* generates a m= SDP from a rejected transceiver.