Echo cancellation gstreamer, android NDK

[Valer Nur]

I do not have an answer on the tactical level with regards to the specific coding issue but, on the strategic level you might want to read the following post discussing echo cancellation on Android http://www.solicall.com/blog/why-echo-cancellation-for-android-is-a-difficult-task/. 

 


On Tuesday, July 1, 2014 10:36 PM, Puyol <paul9510 at hotmail.fr> wrote:
 


Hello!!
My problem is how to cancel echo using jni in android between two devices. 
I tried to use this code but it didn't work to me! 

#include <jni.h>
#include "speex/speex_echo.h"
#include "speex/speex_preprocess.h"
#include "EchoCanceller_jniHeader.h"
SpeexEchoState *st;
SpeexPreprocessState *den;

JNIEXPORT void JNICALL Java_speex_EchoCanceller_open
  (JNIEnv *env, jobject jObj, jint jSampleRate, jint jBufSize, jint
jTotalSize)
{
     //init
     int sampleRate=jSampleRate;
     st = speex_echo_state_init(jBufSize, jTotalSize);
     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_speex_EchoCanceller_process
  (JNIEnv * env, jobject jObj, jshortArray input_frame, jshortArray
echo_frame)
{
  //create native shorts from java shorts
  jshort *native_input_frame = (*env)->GetShortArrayElements(env,
input_frame, NULL);
  jshort *native_echo_frame = (*env)->GetShortArrayElements(env, echo_frame,
NULL);

  //allocate memory for output data
  jint length = (*env)->GetArrayLength(env, input_frame);
  jshortArray temp = (*env)->NewShortArray(env, length);
  jshort *native_output_frame = (*env)->GetShortArrayElements(env, 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(env, length);
  (*env)->SetShortArrayRegion(env, output_shorts, 0, length,
native_output_frame);

  //cleanup and return
  (*env)->ReleaseShortArrayElements(env, input_frame, native_input_frame,
0);
  (*env)->ReleaseShortArrayElements(env, echo_frame, native_echo_frame, 0);
  (*env)->ReleaseShortArrayElements(env, temp, native_output_frame, 0);

  return output_shorts;  
}

JNIEXPORT void JNICALL Java_speex_EchoCanceller_close
  (JNIEnv *env, jobject jObj)
{
     //close
     speex_echo_state_destroy(st);
     speex_preprocess_state_destroy(den);
}

the first problem is that there is no file with name
"EchoCanceller_jniHeader.h"
the second : in SpeexEchoState *st; SpeexPreprocessState *den; I get this
error: Type 'SpeexEchoState' could not be resolved
How can I resolve this?



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