/**
   * Notifies this <tt>Conference</tt> that the ordered list of <tt>Endpoint</tt>s of {@link
   * #speechActivity} i.e. the dominant speaker history has changed.
   *
   * <p>This instance notifies the video <tt>Channel</tt>s about the change so that they may update
   * their last-n lists and report to this instance which <tt>Endpoint</tt>s are to be asked for
   * video keyframes.
   */
  private void speechActivityEndpointsChanged() {
    List<Endpoint> endpoints = null;

    for (Content content : getContents()) {
      if (MediaType.VIDEO.equals(content.getMediaType())) {
        Set<Endpoint> endpointsToAskForKeyframes = null;

        endpoints = speechActivity.getEndpoints();
        for (Channel channel : content.getChannels()) {
          if (!(channel instanceof RtpChannel)) continue;

          RtpChannel rtpChannel = (RtpChannel) channel;
          List<Endpoint> channelEndpointsToAskForKeyframes =
              rtpChannel.speechActivityEndpointsChanged(endpoints);

          if ((channelEndpointsToAskForKeyframes != null)
              && !channelEndpointsToAskForKeyframes.isEmpty()) {
            if (endpointsToAskForKeyframes == null) {
              endpointsToAskForKeyframes = new HashSet<>();
            }
            endpointsToAskForKeyframes.addAll(channelEndpointsToAskForKeyframes);
          }
        }

        if ((endpointsToAskForKeyframes != null) && !endpointsToAskForKeyframes.isEmpty()) {
          content.askForKeyframes(endpointsToAskForKeyframes);
        }
      }
    }
  }
  /**
   * Finds a <tt>Channel</tt> of this <tt>Conference</tt> which receives a specific SSRC and is with
   * a specific <tt>MediaType</tt>.
   *
   * @param receiveSSRC the SSRC of a received RTP stream whose receiving <tt>Channel</tt> in this
   *     <tt>Conference</tt> is to be found
   * @param mediaType the <tt>MediaType</tt> of the <tt>Channel</tt> to be found
   * @return the <tt>Channel</tt> in this <tt>Conference</tt> which receives the specified
   *     <tt>ssrc</tt> and is with the specified <tt>mediaType</tt>; otherwise, <tt>null</tt>
   */
  public Channel findChannelByReceiveSSRC(long receiveSSRC, MediaType mediaType) {
    for (Content content : getContents()) {
      if (mediaType.equals(content.getMediaType())) {
        Channel channel = content.findChannelByReceiveSSRC(receiveSSRC);

        if (channel != null) return channel;
      }
    }
    return null;
  }
  /**
   * Checks whether media recording is currently enabled for this <tt>Conference</tt>.
   *
   * @return <tt>true</tt> if media recording is currently enabled for this <tt>Conference</tt>,
   *     false otherwise.
   */
  public boolean isRecording() {
    boolean recording = this.recording;

    // if one of the contents is not recording, stop all recording
    if (recording) {
      synchronized (contents) {
        for (Content content : contents) {
          MediaType mediaType = content.getMediaType();

          if (!MediaType.VIDEO.equals(mediaType) && !MediaType.AUDIO.equals(mediaType)) continue;
          if (!content.isRecording()) recording = false;
        }
      }
    }
    if (this.recording != recording) setRecording(recording);

    return this.recording;
  }
  /**
   * Attempts to enable or disable media recording for this <tt>Conference</tt>.
   *
   * @param recording whether to enable or disable recording.
   * @return the state of the media recording for this <tt>Conference</tt> after the attempt to
   *     enable (or disable).
   */
  public boolean setRecording(boolean recording) {
    if (recording != this.recording) {
      if (recording) {
        // try enable recording
        if (logger.isDebugEnabled()) {
          logger.debug("Starting recording for conference with id=" + getID());
        }

        String path = getRecordingPath();
        boolean failedToStart = !checkRecordingDirectory(path);

        if (!failedToStart) {
          RecorderEventHandler handler = getRecorderEventHandler();

          if (handler == null) failedToStart = true;
        }
        if (!failedToStart) {
          EndpointRecorder endpointRecorder = getEndpointRecorder();

          if (endpointRecorder == null) {
            failedToStart = true;
          } else {
            for (Endpoint endpoint : getEndpoints()) endpointRecorder.updateEndpoint(endpoint);
          }
        }

        /*
         * The Recorders of the Contents need to share a single
         * Synchronizer, we take it from the first Recorder.
         */
        boolean first = true;
        Synchronizer synchronizer = null;

        for (Content content : contents) {
          MediaType mediaType = content.getMediaType();

          if (!MediaType.VIDEO.equals(mediaType) && !MediaType.AUDIO.equals(mediaType)) {
            continue;
          }

          if (!failedToStart) failedToStart = !content.setRecording(true, path);
          if (failedToStart) break;

          if (first) {
            first = false;
            synchronizer = content.getRecorder().getSynchronizer();
          } else {
            Recorder recorder = content.getRecorder();

            if (recorder != null) recorder.setSynchronizer(synchronizer);
          }

          content.feedKnownSsrcsToSynchronizer();
        }

        if (failedToStart) {
          recording = false;
          logger.warn("Failed to start media recording for conference " + getID());
        }
      }

      // either we were asked to disable recording, or we failed to
      // enable it
      if (!recording) {
        if (logger.isDebugEnabled()) {
          logger.debug("Stopping recording for conference with id=" + getID());
        }

        for (Content content : contents) {
          MediaType mediaType = content.getMediaType();

          if (MediaType.AUDIO.equals(mediaType) || MediaType.VIDEO.equals(mediaType)) {
            content.setRecording(false, null);
          }
        }

        if (recorderEventHandler != null) recorderEventHandler.close();
        recorderEventHandler = null;
        recordingPath = null;
        recordingDirectory = null;

        if (endpointRecorder != null) endpointRecorder.close();
        endpointRecorder = null;
      }

      this.recording = recording;
    }

    return this.recording;
  }