RTP: Add a baseline echo suppressor. (a8a10096) · Commits · e / os / android_frameworks_base

voip/jni/rtp/Android.mk

+1 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@ LOCAL_MODULE := librtp_jni
		LOCAL_SRC_FILES := \
		AudioCodec.cpp \
		AudioGroup.cpp \
		EchoSuppressor.cpp \
		RtpStream.cpp \
		util.cpp \
		rtp_jni.cpp

voip/jni/rtp/AudioGroup.cpp

+5 −2

Original line number	Diff line number	Diff line
		@@ -44,6 +44,7 @@
		#include "JNIHelp.h"

		#include "AudioCodec.h"
		#include "EchoSuppressor.h"

		extern int parse(JNIEnv env, jstring jAddress, int port, sockaddr_storage ss);

		@@ -766,7 +767,9 @@ bool AudioGroup::DeviceThread::threadLoop()
		}
		LOGD("latency: output %d, input %d", track.latency(), record.latency());

		// TODO: initialize echo canceler here.
		// Initialize echo canceler.
		EchoSuppressor echo(sampleRate, sampleCount, sampleCount * 2 +
		(track.latency() + record.latency()) * sampleRate / 1000);

		// Give device socket a reasonable buffer size.
		setsockopt(deviceSocket, SOL_SOCKET, SO_RCVBUF, &output, sizeof(output));
		@@ -839,7 +842,7 @@ bool AudioGroup::DeviceThread::threadLoop()
		if (mode == NORMAL) {
		send(deviceSocket, input, sizeof(input), MSG_DONTWAIT);
		} else {
		// TODO: Echo canceller runs here.
		echo.run(output, input);
		send(deviceSocket, input, sizeof(input), MSG_DONTWAIT);
		}
		}

voip/jni/rtp/EchoSuppressor.cpp

0 → 100644

+171 −0

Original line number	Diff line number	Diff line
		/*
		* Copyrightm (C) 2010 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#include <stdio.h>
		#include <stdint.h>
		#include <math.h>

		#define LOG_TAG "Echo"
		#include <utils/Log.h>

		#include "EchoSuppressor.h"

		EchoSuppressor::EchoSuppressor(int sampleRate, int sampleCount, int tailLength)
		{
		int scale = 1;
		while (tailLength > 200 * scale) {
		scale <<= 1;
		}
		if (scale > sampleCount) {
		scale = sampleCount;
		}

		mScale = scale;
		mSampleCount = sampleCount;
		mWindowSize = sampleCount / scale;
		mTailLength = (tailLength + scale - 1) / scale;
		mRecordLength = (sampleRate + sampleCount - 1) / sampleCount;
		mRecordOffset = 0;

		mXs = new float[mTailLength + mWindowSize];
		memset(mXs, 0, sizeof(float) * (mTailLength + mWindowSize));
		mXYs = new float[mTailLength];
		memset(mXYs, 0, sizeof(float) * mTailLength);
		mXXs = new float[mTailLength];
		memset(mXYs, 0, sizeof(float) * mTailLength);
		mYY = 0;

		mXYRecords = new float[mRecordLength * mTailLength];
		memset(mXYRecords, 0, sizeof(float) * mRecordLength * mTailLength);
		mXXRecords = new float[mRecordLength * mWindowSize];
		memset(mXXRecords, 0, sizeof(float) * mRecordLength * mWindowSize);
		mYYRecords = new float[mRecordLength];
		memset(mYYRecords, 0, sizeof(float) * mRecordLength);

		mLastX = 0;
		mLastY = 0;
		}

		EchoSuppressor::~EchoSuppressor()
		{
		delete [] mXs;
		delete [] mXYs;
		delete [] mXXs;
		delete [] mXYRecords;
		delete [] mXXRecords;
		delete [] mYYRecords;
		}

		void EchoSuppressor::run(int16_t playbacked, int16_t recorded)
		{
		float *records;

		// Update Xs.
		for (int i = 0; i < mTailLength; ++i) {
		mXs[i] = mXs[mWindowSize + i];
		}
		for (int i = 0, j = 0; i < mWindowSize; ++i, j += mScale) {
		float sum = 0;
		for (int k = 0; k < mScale; ++k) {
		float x = playbacked[j + k] >> 8;
		mLastX += x;
		sum += (mLastX >= 0) ? mLastX : -mLastX;
		mLastX = 0.005f * mLastX - x;
		}
		mXs[mTailLength - 1 + i] = sum;
		}

		// Update XXs and XXRecords.
		for (int i = 0; i < mTailLength - mWindowSize; ++i) {
		mXXs[i] = mXXs[mWindowSize + i];
		}
		records = &mXXRecords[mRecordOffset * mWindowSize];
		for (int i = 0, j = mTailLength - mWindowSize; i < mWindowSize; ++i, ++j) {
		float xx = mXs[mTailLength - 1 + i] * mXs[mTailLength - 1 + i];
		mXXs[j] = mXXs[j - 1] + xx - records[i];
		records[i] = xx;
		if (mXXs[j] < 0) {
		mXXs[j] = 0;
		}
		}

		// Compute Ys.
		float ys[mWindowSize];
		for (int i = 0, j = 0; i < mWindowSize; ++i, j += mScale) {
		float sum = 0;
		for (int k = 0; k < mScale; ++k) {
		float y = recorded[j + k] >> 8;
		mLastY += y;
		sum += (mLastY >= 0) ? mLastY : -mLastY;
		mLastY = 0.005f * mLastY - y;
		}
		ys[i] = sum;
		}

		// Update YY and YYRecords.
		float yy = 0;
		for (int i = 0; i < mWindowSize; ++i) {
		yy += ys[i] * ys[i];
		}
		mYY += yy - mYYRecords[mRecordOffset];
		mYYRecords[mRecordOffset] = yy;
		if (mYY < 0) {
		mYY = 0;
		}

		// Update XYs and XYRecords.
		records = &mXYRecords[mRecordOffset * mTailLength];
		for (int i = 0; i < mTailLength; ++i) {
		float xy = 0;
		for (int j = 0;j < mWindowSize; ++j) {
		xy += mXs[i + j] * ys[j];
		}
		mXYs[i] += xy - records[i];
		records[i] = xy;
		if (mXYs[i] < 0) {
		mXYs[i] = 0;
		}
		}

		// Computes correlations from XYs, XXs, and YY.
		float weight = 1.0f / (mYY + 1);
		float correlation = 0;
		int latency = 0;
		for (int i = 0; i < mTailLength; ++i) {
		float c = mXYs[i] * mXYs[i] * weight / (mXXs[i] + 1);
		if (c > correlation) {
		correlation = c;
		latency = i;
		}
		}

		correlation = sqrtf(correlation);
		if (correlation > 0.3f) {
		float factor = 1.0f - correlation;
		factor *= factor;
		for (int i = 0; i < mSampleCount; ++i) {
		recorded[i] *= factor;
		}
		}
		// LOGI("latency %5d, correlation %.10f", latency, correlation);


		// Increase RecordOffset.
		++mRecordOffset;
		if (mRecordOffset == mRecordLength) {
		mRecordOffset = 0;
		}
		}

voip/jni/rtp/EchoSuppressor.h

0 → 100644

+51 −0

Original line number	Diff line number	Diff line
		/*
		* Copyrightm (C) 2010 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#ifndef __ECHO_SUPPRESSOR_H__
		#define __ECHO_SUPPRESSOR_H__

		#include <stdint.h>

		class EchoSuppressor
		{
		public:
		// The sampleCount must be power of 2.
		EchoSuppressor(int sampleRate, int sampleCount, int tailLength);
		~EchoSuppressor();
		void run(int16_t playbacked, int16_t recorded);

		private:
		int mScale;
		int mSampleCount;
		int mWindowSize;
		int mTailLength;
		int mRecordLength;
		int mRecordOffset;

		float *mXs;
		float *mXYs;
		float *mXXs;
		float mYY;

		float *mXYRecords;
		float *mXXRecords;
		float *mYYRecords;

		float mLastX;
		float mLastY;
		};

		#endif