change video resolution in sip mid call

[mansuu]

I want to change video resolution in sip mid call based on network speed.I tried a lot but failed One of my trials is i reinvite second person with updated resolution code is NgnAVSession session= NgnAVSession.getSession(new NgnPredicate() {

            @Override
            public boolean apply(NgnAVSession session) {
                // TODO Auto-generated method stub
                return session.isActive();
            }

        });
        //INgnConfigurationService configurationService = Engine.getInstance().getConfigurationService();
        MediaSessionMgr.defaultsSetPrefVideoSize(tmedia_pref_video_size_t.tmedia_pref_video_size_720p);
        //session.getMediaSessionMgr().defaultsSetPrefVideoSize(tmedia_pref_video_size_t.tmedia_pref_video_size_720p);

    session.makeCall(remoteUri);

but it does not work also.