参考以下链接
因为工程中只需要mp3转pcm，所以对此做了些裁剪，记录一下。
import android.media.MediaCodec;
import android.media.MediaExtractor;
import android.media.MediaFormat;
import android.media.MediaPlayer;
import android.os.Build;
import android.text.TextUtils;
import android.util.Log;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import androidx.annotation.RequiresApi;
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
public class TransPCMHandlerPure {
private String srcFile;
private String outFile;
private long rangeStart = -1;
private long rangeEnd = -1;
private OnProgressListener listener;
public TransPCMHandlerPure(String srcFile, String outFile) {
this(srcFile, outFile, null);
}
public TransPCMHandlerPure(String srcFile, String outFile, OnProgressListener listener) {
this(srcFile, outFile, -1, -1, listener);
}
public TransPCMHandlerPure(String srcFile, String outFile, long rangeStart, long rangeEnd, OnProgressListener listener) {
this.srcFile = srcFile;
this.outFile = outFile;
this.rangeStart = rangeStart;
this.rangeEnd = rangeEnd;
this.listener = listener;
}
public void start() {
DecodeTask task = new DecodeTask(srcFile, outFile, listener);
task.setRangeTime(rangeStart, rangeEnd);
new Thread(task).start();
}
public void setRangeTime(long rangeStart, long rangeEnd) {
this.rangeStart = rangeStart;
this.rangeEnd = rangeEnd;
}
public void setListener(OnProgressListener listener) {
this.listener = listener;
}
private static class DecodeTask implements Runnable{
private static final long TIME_OUT = 5000;
private MediaExtractor extractor;
private String srcFile;
private MediaCodec codec;
private String outFile;
private OnProgressListener listener;
private long rangeStart;
private long rangeEnd;
private int duration = 0;
private OutputStream mOutput;
public void setRangeTime(long rangeStart, long rangeEnd) {
this.rangeStart = rangeStart;
this.rangeEnd = rangeEnd;
}
public DecodeTask(String srcFile, String outFile, OnProgressListener listener) {
this.srcFile = srcFile;
this.outFile = outFile;
this.listener = listener;
}
@Override
public void run() {
if (listener != null) {
listener.onStart();
}
boolean isPrepare = false;
try {
prepare();
isPrepare = true;
} catch (IOException e) {
e.printStackTrace();
}
if (isPrepare) {
output();
}
release();
if (!isPrepare && listener != null) {
listener.onFail();
}
}
private void release() {
if (extractor != null) {
extractor.release();
extractor = null;
}
if (codec != null) {
codec.stop();
codec.release();
codec = null;
}
}
private void prepare() throws IOException {
extractor = new MediaExtractor();
extractor.setDataSource(srcFile);
int numTracks = extractor.getTrackCount();
for (int i = 0; i < numTracks; i++) {
MediaFormat format = extractor.getTrackFormat(i);
String mine = format.getString(MediaFormat.KEY_MIME);
if (!TextUtils.isEmpty(mine) && mine.startsWith("audio")) {
extractor.selectTrack(i);
try {
duration = format.getInteger(MediaFormat.KEY_DURATION) / 1000;
} catch (Exception e) {
e.printStackTrace();
MediaPlayer mediaPlayer = new MediaPlayer();
mediaPlayer.setDataSource(srcFile);
mediaPlayer.prepare();
duration = mediaPlayer.getDuration();
mediaPlayer.release();
}
codec = MediaCodec.createDecoderByType(mine);
codec.configure(format, null, null, 0);
codec.start();
break;
}
}
createFile(outFile + ".pcm", true);
mOutput = new DataOutputStream(new FileOutputStream(outFile + ".pcm"));
}
private void output(){
ByteBuffer[] inputBuffers = codec.getInputBuffers();
ByteBuffer[] outputBuffers = codec.getOutputBuffers();
MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
if (rangeStart > 0) {//如果有裁剪，seek到裁剪的地方
extractor.seekTo(rangeStart * 1000, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
}
boolean isEOS = false;
while (true){
long timestamp = 0;
if (!isEOS) {
int inIndex = codec.dequeueInputBuffer(TIME_OUT);
if (inIndex >= 0) {
ByteBuffer buffer = inputBuffers[inIndex];
int sampleSize = extractor.readSampleData(buffer, 0);
long timestampTemp = extractor.getSampleTime();
timestamp = timestampTemp / 1000;
if (rangeEnd > 0 && timestamp > rangeEnd) {
sampleSize = -1;
}
if (sampleSize <= 0) {
codec.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
isEOS = true;
} else {
codec.queueInputBuffer(inIndex, 0, sampleSize, timestampTemp, 0);
extractor.advance();
}
}
}
int outIndex = codec.dequeueOutputBuffer(info, TIME_OUT);
switch (outIndex) {
case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:
outputBuffers = codec.getOutputBuffers();
break;
case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:
break;
case MediaCodec.INFO_TRY_AGAIN_LATER:
break;
default:
ByteBuffer buffer = outputBuffers[outIndex];
byte[] outData = new byte[info.size];
buffer.get(outData, 0, info.size);
codec.releaseOutputBuffer(outIndex, true);
try {
mOutput.write(outData);
} catch (IOException e) {
e.printStackTrace();
}
if (listener != null) {
listener.onProgress(rangeEnd > 0 ? (int) rangeEnd : duration, rangeStart > 0 ? (int) (timestamp - rangeStart) : (int) timestamp);
}
break;
}
}
}
}
private static boolean createFile(String filePath, boolean recreate) {
if (TextUtils.isEmpty(filePath)) {
return false;
}
try {
File file = new File(filePath);
if (file.exists()) {
if (recreate) {
file.delete();
file.createNewFile();
}
} else {
// 如果路径不存在，先创建路径
File parentFile = file.getParentFile();
if (!parentFile.exists()) {
parentFile.mkdirs();
}
file.createNewFile();
}
} catch (Exception e) {
return false;
}
return true;
}
public interface OnProgressListener {
void onStart();
void onProgress(int max, int progress);
void onSuccess();
void onFail();
}
}
