SPEEX - AEC on Android device for stereo input

Question

Sample rate: 16k

I m using <speex_echo_state_init_mc(jBufSize, jTotalSize, 2 , 2>

Also as suggested in the doc frame_size should be of 20 ms & filter_length is of 100-500ms

I tried using frame_size as 16000 * 20/1000 = 320 & filter_size as 16000 * 500/1000 = 32000

Also tried other values for fram_size & filter_lenght but no luck !

JNIEXPORT void JNICALL Java_com_speex_SpeexInterface_open
  (JNIEnv *env, jobject jObj, jint jSampleRate, jint jBufSize, jint jTotalSize) {
     //init
     int sampleRate = jSampleRate;
     st = speex_echo_state_init_mc(jBufSize, jTotalSize, 2 , 2);
     den = speex_preprocess_state_init(jBufSize, sampleRate);
     speex_echo_ctl(st, SPEEX_ECHO_SET_SAMPLING_RATE, &sampleRate);
     speex_preprocess_ctl(den, SPEEX_PREPROCESS_SET_ECHO_STATE, st);
}

JNIEXPORT jshortArray JNICALL Java_com_speex_SpeexInterface_process
  (JNIEnv * env, jobject jObj, jshortArray input_frame, jshortArray echo_frame) {
  //create native shorts from java shorts
  jshort *native_input_frame = env->GetShortArrayElements(input_frame, 0);
  jshort *native_echo_frame = env->GetShortArrayElements(echo_frame, 0);
 
  //allocate memory for output data
  jint length = env->GetArrayLength(input_frame);
  jshortArray temp = env->NewShortArray(length);
  jshort *native_output_frame = env->GetShortArrayElements(temp, 0);
 
  //call echo cancellation
  speex_echo_cancellation(st, native_input_frame, native_echo_frame, native_output_frame);
  
  //preprocess output frame
  speex_preprocess_run(den, native_output_frame);
  
  //convert native output to java layer output
  jshortArray output_shorts = env->NewShortArray(length);
  env->SetShortArrayRegion(output_shorts, 0, length, native_output_frame);
  
  //cleanup and return
  env->ReleaseShortArrayElements(input_frame, native_input_frame, 0);
  env->ReleaseShortArrayElements(echo_frame, native_echo_frame, 0);
  env->ReleaseShortArrayElements(temp, native_output_frame, 0);
  return output_shorts;  
}

Please help me where I making mistake !!