WebRTC - Echo issue in Multiple calls on android devices

Question

I am working on an Android app that allows live chat and call functionality. I am new to WebRTC in android. I am trying to add multiple call functionality using WebRTC. I got success in connecting multiple P2P calls (Upto 6 users are easily gets connected using Mesh Topology.

Here are the steps that I am following:

A => B Call successful ==> Result: audio clear no problem on both the ends A => C Adding New Caller C from A ==> Result: audio clear no problem on both the ends. C => B in background C gives call to B and gets accepted on B's end => Result: audio clear no problem on all the ends.

Now, All 3 participants are connected and can communicate easily.

The issue is:

When any of the participants leaves the call, Any of the remaining participants are hearing Echo of their own voice.

All my call related setups are done using RingRTC. Please help if anyone has faced this issue.

I tried setting up Noisce Supressors, AcousticEchoCanceler and other options for each remaining audio sessions as below. But its not helping.

public void enable(int audioSession) {
    Logging.d(TAG, "enable(audioSession=" + audioSession + ")");
    assertTrue(aec == null);
    assertTrue(agc == null);
    assertTrue(ns == null);

    // Add logging of supported effects but filter out "VoIP effects", i.e.,
    // AEC, AEC and NS.
    for (Descriptor d : AudioEffect.queryEffects()) {
      if (effectTypeIsVoIP(d.type) || DEBUG) {
        Logging.d(TAG, "name: " + d.name + ", "
            + "mode: " + d.connectMode + ", "
            + "implementor: " + d.implementor + ", "
            + "UUID: " + d.uuid);
      }
    }

    if (isAcousticEchoCancelerSupported()) {
      // Create an AcousticEchoCanceler and attach it to the AudioRecord on
      // the specified audio session.
      aec = AcousticEchoCanceler.create(audioSession);
      if (aec != null) {
        boolean enabled = aec.getEnabled();
        boolean enable = shouldEnableAec && canUseAcousticEchoCanceler();
        if (aec.setEnabled(enable) != AudioEffect.SUCCESS) {
          Logging.e(TAG, "Failed to set the AcousticEchoCanceler state");
        }
        Logging.d(TAG, "AcousticEchoCanceler: was "
            + (enabled ? "enabled" : "disabled")
            + ", enable: " + enable + ", is now: "
            + (aec.getEnabled() ? "enabled" : "disabled"));
      } else {
        Logging.e(TAG, "Failed to create the AcousticEchoCanceler instance");
      }
    }

    if (isAutomaticGainControlSupported()) {
      // Create an AutomaticGainControl and attach it to the AudioRecord on
      // the specified audio session.
      agc = AutomaticGainControl.create(audioSession);
      if (agc != null) {
        boolean enabled = agc.getEnabled();
        boolean enable = shouldEnableAgc && canUseAutomaticGainControl();
        if (agc.setEnabled(enable) != AudioEffect.SUCCESS) {
          Logging.e(TAG, "Failed to set the AutomaticGainControl state");
        }
        Logging.d(TAG, "AutomaticGainControl: was "
            + (enabled ? "enabled" : "disabled")
            + ", enable: " + enable + ", is now: "
            + (agc.getEnabled() ? "enabled" : "disabled"));
      } else {
        Logging.e(TAG, "Failed to create the AutomaticGainControl instance");
      }
    }

    if (isNoiseSuppressorSupported()) {
      // Create an NoiseSuppressor and attach it to the AudioRecord on the
      // specified audio session.
      ns = NoiseSuppressor.create(audioSession);
      if (ns != null) {
        boolean enabled = ns.getEnabled();
        boolean enable = shouldEnableNs && canUseNoiseSuppressor();
        if (ns.setEnabled(enable) != AudioEffect.SUCCESS) {
          Logging.e(TAG, "Failed to set the NoiseSuppressor state");
        }
        Logging.d(TAG, "NoiseSuppressor: was "
            + (enabled ? "enabled" : "disabled")
            + ", enable: " + enable + ", is now: "
            + (ns.getEnabled() ? "enabled" : "disabled"));
      } else {
        Logging.e(TAG, "Failed to create the NoiseSuppressor instance");
      }
    }
  }