RTP: integrate the echo canceller from speex.

Currently the filter_length is set to one second.
Will change that when we have a better idea.

Change-Id: Ia942a8fff00b096de8ff0049a448816ea9a68068

2 files changed, 18 insertions, 6 deletions

diff --git a/voip/jni/rtp/Android.mk b/voip/jni/rtp/Android.mk
index a364355..3bd85aa 100644
--- a/voip/jni/rtp/Android.mk
+++ b/voip/jni/rtp/Android.mk
@@ -32,10 +32,11 @@ LOCAL_SHARED_LIBRARIES := \
 	libutils \
 	libmedia
 
-LOCAL_STATIC_LIBRARIES :=
+LOCAL_STATIC_LIBRARIES := libspeex
 
 LOCAL_C_INCLUDES += \
-	$(JNI_H_INCLUDE)
+	$(JNI_H_INCLUDE) \
+	external/speex/include
 
 LOCAL_CFLAGS += -fvisibility=hidden
 
diff --git a/voip/jni/rtp/AudioGroup.cpp b/voip/jni/rtp/AudioGroup.cpp
index bb45a9a..b5a4e22 100644
--- a/voip/jni/rtp/AudioGroup.cpp
+++ b/voip/jni/rtp/AudioGroup.cpp
@@ -40,6 +40,8 @@
 #include <media/AudioTrack.h>
 #include <media/mediarecorder.h>
 
+#include <speex/speex_echo.h>
+
 #include "jni.h"
 #include "JNIHelp.h"
 
@@ -445,6 +447,8 @@ private:
     int mDeviceSocket;
     AudioTrack mTrack;
     AudioRecord mRecord;
+    
+    SpeexEchoState *mEchoState;
 
     bool networkLoop();
     bool deviceLoop();
@@ -506,6 +510,7 @@ AudioGroup::AudioGroup()
     mEventQueue = -1;
     mDtmfEvent = -1;
     mDeviceSocket = -1;
+    mEchoState = NULL;
     mNetworkThread = new NetworkThread(this);
     mDeviceThread = new DeviceThread(this);
 }
@@ -518,6 +523,9 @@ AudioGroup::~AudioGroup()
     mRecord.stop();
     close(mEventQueue);
     close(mDeviceSocket);
+    if (mEchoState) {
+        speex_echo_state_destroy(mEchoState);
+    }
     while (mChain) {
         AudioStream *next = mChain->mNext;
         delete mChain;
@@ -566,7 +574,8 @@ bool AudioGroup::set(int sampleRate, int sampleCount)
     }
     LOGD("latency: output %d, input %d", mTrack.latency(), mRecord.latency());
 
-    // TODO: initialize echo canceler here.
+    // Initialize echo canceller.
+    mEchoState = speex_echo_state_init(sampleCount, sampleRate);
 
     // Create device socket.
     int pair[2];
@@ -633,6 +642,7 @@ bool AudioGroup::setMode(int mode)
     if (mode == MUTED) {
         mRecord.stop();
     } else {
+        speex_echo_state_reset(mEchoState);
         mRecord.start();
     }
 
@@ -793,7 +803,7 @@ bool AudioGroup::deviceLoop()
 
             status_t status = mRecord.obtainBuffer(&buffer, 1);
             if (status == NO_ERROR) {
-                int count = (buffer.frameCount < toRead) ?
+                int count = ((int)buffer.frameCount < toRead) ?
                         buffer.frameCount : toRead;
                 memcpy(&input[mSampleCount - toRead], buffer.i8, count * 2);
                 toRead -= count;
@@ -817,8 +827,9 @@ bool AudioGroup::deviceLoop()
         if (mMode == NORMAL) {
             send(mDeviceSocket, input, sizeof(input), MSG_DONTWAIT);
         } else {
-            // TODO: Echo canceller runs here.
-            send(mDeviceSocket, input, sizeof(input), MSG_DONTWAIT);
+            int16_t result[mSampleCount];
+            speex_echo_cancellation(mEchoState, input, output, result);
+            send(mDeviceSocket, result, sizeof(result), MSG_DONTWAIT);
         }
     }
     return true;