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/*
* Copyright (C) 2008 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.
*/
package android.media;
import android.util.Log;
import java.io.InputStream;
import java.io.IOException;
/**
* AmrInputStream
* @hide
*/
public final class AmrInputStream extends InputStream
{
static {
System.loadLibrary("media_jni");
}
private final static String TAG = "AmrInputStream";
// frame is 20 msec at 8.000 khz
private final static int SAMPLES_PER_FRAME = 8000 * 20 / 1000;
// pcm input stream
private InputStream mInputStream;
// native handle
private int mGae;
// result amr stream
private final byte[] mBuf = new byte[SAMPLES_PER_FRAME * 2];
private int mBufIn = 0;
private int mBufOut = 0;
// helper for bytewise read()
private byte[] mOneByte = new byte[1];
/**
* Create a new AmrInputStream, which converts 16 bit PCM to AMR
* @param inputStream InputStream containing 16 bit PCM.
*/
public AmrInputStream(InputStream inputStream) {
mInputStream = inputStream;
mGae = GsmAmrEncoderNew();
GsmAmrEncoderInitialize(mGae);
}
@Override
public int read() throws IOException {
int rtn = read(mOneByte, 0, 1);
return rtn == 1 ? (0xff & mOneByte[0]) : -1;
}
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
@Override
public int read(byte[] b, int offset, int length) throws IOException {
if (mGae == 0) throw new IllegalStateException("not open");
// local buffer of amr encoded audio empty
if (mBufOut >= mBufIn) {
// reset the buffer
mBufOut = 0;
mBufIn = 0;
// fetch a 20 msec frame of pcm
for (int i = 0; i < SAMPLES_PER_FRAME * 2; ) {
int n = mInputStream.read(mBuf, i, SAMPLES_PER_FRAME * 2 - i);
if (n == -1) return -1;
i += n;
}
// encode it
mBufIn = GsmAmrEncoderEncode(mGae, mBuf, 0, mBuf, 0);
}
// return encoded audio to user
if (length > mBufIn - mBufOut) length = mBufIn - mBufOut;
System.arraycopy(mBuf, mBufOut, b, offset, length);
mBufOut += length;
return length;
}
@Override
public void close() throws IOException {
try {
if (mInputStream != null) mInputStream.close();
} finally {
mInputStream = null;
try {
if (mGae != 0) GsmAmrEncoderCleanup(mGae);
} finally {
try {
if (mGae != 0) GsmAmrEncoderDelete(mGae);
} finally {
mGae = 0;
}
}
}
}
@Override
protected void finalize() throws Throwable {
if (mGae != 0) {
close();
throw new IllegalStateException("someone forgot to close AmrInputStream");
}
}
//
// AudioRecord JNI interface
//
private static native int GsmAmrEncoderNew();
private static native void GsmAmrEncoderInitialize(int gae);
private static native int GsmAmrEncoderEncode(int gae,
byte[] pcm, int pcmOffset, byte[] amr, int amrOffset) throws IOException;
private static native void GsmAmrEncoderCleanup(int gae);
private static native void GsmAmrEncoderDelete(int gae);
}
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