第一次写这样的博文，写得不好，望大家及时指出博文中的错误，以便于相互学习。
本来主要介绍如何使用mediacodec来转码音频，同时实现音频的裁剪。对于mediacodec相信大家都不陌生，没做过也听过。
转码音频需要的知识点
1、音频基础知识，什么是pcm，什么是音频格式（MP3、aac等），这里给大家推荐一篇博文，/kevindgk/article/details/52924779。
2、mediacodec的基础知识和api调用，mediacodec是典型的CS模式，也就是客户端-服务器模式，建议大家多看看官网api，
这里给大家推荐一篇中文版的api，MediaCodec中文api
转码流程
解码线程：FILE—解码—PCM队列
编码线程：PCM队列—编码—FILE
系统版本和相关Api类
sdk版本>=16；MediaCodec、MediaExtractor
解码线程
主要流程是通过MediaExtractor读取一帧数据，然后进行解码并放入PCM队列，流程分为prepare—decode—release; 相关代码分别如下： 主要线程里面的流程：@Overridepublic void run() {TransAacHandlerPure.logMsg("decodec run");if (listener != null) {listener.onStart();}boolean isPrepare = false;try {prepare();//初始化isPrepare = true;} catch (IOException e) {e.printStackTrace();}TransAacHandlerPure.logMsg("decodec isPrepare " + isPrepare);if (isPrepare) {decode();//解码}release();//释放资源if (!isPrepare && listener != null) {listener.onFail();}isFinish = true;}
prepare里面的代码如下：
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();TransAacHandlerPure.logMsg("New decode codec start:" + format.toString());break;}}// createFile(outFile + ".pcm", true);//测试 输出pcm格式// mOutput = new DataOutputStream(new FileOutputStream(outFile + ".pcm"));}
decode方法如下：
private void decode() {ByteBuffer[] inputBuffers = codec.getInputBuffers();ByteBuffer[] outputBuffers = codec.getOutputBuffers();MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();TransAacHandlerPure.logMsg("loopDecode start");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;TransAacHandlerPure.logMsg("loopDecode readSampleData end sampleSize " + sampleSize + " buffer.capacity()=" + buffer.capacity());TransAacHandlerPure.logMsg("loopDecode readSampleData end timestamp" + timestamp);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);//TransAacHandlerPure.logMsg(" switch (outIndex)");switch (outIndex) {case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:outputBuffers = codec.getOutputBuffers();TransAacHandlerPure.logMsg("dequeueOutputBuffer INFO_OUTPUT_BUFFERS_CHANGED!");break;case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:MediaFormat mf = codec.getOutputFormat();//开始编码线程EncodeTask encodeTask = new EncodeTask(outFile, this, listener);int sampleRate = mf.getInteger(MediaFormat.KEY_SAMPLE_RATE);int pcmEncoding = mf.getInteger(MediaFormat.KEY_PCM_ENCODING);int channelCount = mf.getInteger(MediaFormat.KEY_CHANNEL_COUNT);encodeTask.setAudioParams(sampleRate, pcmEncoding, channelCount);new Thread(encodeTask).start();TransAacHandlerPure.logMsg("New format " + mf.toString());break;case MediaCodec.INFO_TRY_AGAIN_LATER:TransAacHandlerPure.logMsg("dequeueOutputBuffer timed out!");break;default:if (last == 0) {last = System.currentTimeMillis();}long now = System.currentTimeMillis();TransAacHandlerPure.logMsg("解码时间：" + (now - last) + " info.size " + info.size);last = now;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();}pushAvFrame(outData);if (listener != null) {listener.onProgress(rangeEnd > 0 ? (int) rangeEnd : duration, rangeStart > 0 ? (int) (timestamp - rangeStart) : (int) timestamp);}break;}// All decoded frames have been rendered, we can stop playing nowif ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {TransAacHandlerPure.logMsg("OutputBuffer BUFFER_FLAG_END_OF_STREAM");break;}}}
release相关代码
private void release() {if (extractor != null) {extractor.release();extractor = null;}if (codec != null) {codec.stop();codec.release();codec = null;}}
编码线程
主要流程跟解码线程类似，需要说明的是编码线程开始是在解码返回MediaCodec.INFO_OUTPUT_FORMAT_CHANGED这个状态的时候，因为在这个时候可以拿到编码需要的一些必要参数，如采样率等等，虽然也可以在从MediaExtractor里面拿，但是这样可能有些机型拿不到一些数据，所以我认为在这里拿是比较合适的。闲话不多说，直接看代码： run方法：@Overridepublic void run() {boolean isPrepare = false;try {prepare();isPrepare = true;} catch (IOException e) {e.printStackTrace();}if (isPrepare && obtain != null) {encode();}release();if (listener != null) {if (isPrepare) {listener.onSuccess();} else {listener.onFail();}}}
prepare方法，关于比特率的设置，大家多参考之前关于音频基础知识的那篇博文，这个直接影响到文件大小和音质
private void prepare() throws IOException {String mime = MediaFormat.MIMETYPE_AUDIO_AAC;encoder = MediaCodec.createEncoderByType(mime);MediaFormat format = MediaFormat.createAudioFormat(mime, sampleRate, channelCount);format.setInteger(MediaFormat.KEY_BIT_RATE, 96000);format.setInteger(MediaFormat.KEY_PCM_ENCODING, pcmEncoding);format.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, 20 * 1024);format.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);logMsg(" New " + format.toString());encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);encoder.start();createFile(outFile, true);mOutput = new DataOutputStream(new FileOutputStream(outFile));}
encode方法，要注意aac写入的时候需要加入头部分，关于aac格式介绍，大家参考这篇博文-aac格式介绍
private void encode() {boolean isFinish = false;while (true) {if (!isFinish) {byte[] rawData = obtain.getRawFrame();if (rawData == null) {if (obtain.isFinish()) {isFinish = true;int inIndex = encoder.dequeueInputBuffer(TIME_OUT);encoder.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);} else {try {Thread.sleep(10);} catch (InterruptedException e) {e.printStackTrace();}}continue;}ByteBuffer[] inputBuffers = encoder.getInputBuffers();int inIndex = encoder.dequeueInputBuffer(TIME_OUT);if (inIndex >= 0) {ByteBuffer inputBuffer = inputBuffers[inIndex];inputBuffer.clear();inputBuffer.put(rawData);encoder.queueInputBuffer(inIndex, 0, rawData.length, System.nanoTime(), 0);}}ByteBuffer[] outputBuffers = encoder.getOutputBuffers();MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();int outIndex = encoder.dequeueOutputBuffer(info, TIME_OUT);if (outIndex >= 0) {if (last == 0) {last = System.currentTimeMillis();}long now = System.currentTimeMillis();TransAacHandlerPure.logMsg("编码码时间：" + (now - last) + " info.size " + info.size);last = now;while (outIndex >= 0) {ByteBuffer outputBuffer = outputBuffers[outIndex];int len = info.size + 7;byte[] outData = new byte[len];addADTStoPacket(outData, len);outputBuffer.get(outData, 7, info.size);encoder.releaseOutputBuffer(outIndex, false);try {mOutput.write(outData);} catch (Exception e) {e.printStackTrace();} catch (Error e) {e.printStackTrace();}outIndex = encoder.dequeueOutputBuffer(info, TIME_OUT);}}if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {VLog.d("encode OutputBuffer BUFFER_FLAG_END_OF_STREAM");break;}}}
加入aac头方法
/*** 给编码出的aac裸流添加adts头字段** @param packet 要空出前7个字节，否则会搞乱数据* @param packetLen*/private void addADTStoPacket(byte[] packet, int packetLen) {int profile = 2; //AAC LCint freqIdx = 4; //44.1KHzint chanCfg = 2; //CPEpacket[0] = (byte) 0xFF;packet[1] = (byte) 0xF9;packet[2] = (byte) (((profile - 1) << 6) + (freqIdx << 2) + (chanCfg >> 2));packet[3] = (byte) (((chanCfg & 3) << 6) + (packetLen >> 11));packet[4] = (byte) ((packetLen & 0x7FF) >> 3);packet[5] = (byte) (((packetLen & 7) << 5) + 0x1F);packet[6] = (byte) 0xFC;}
release方法
private void release() {if (encoder != null) {encoder.stop();encoder.release();encoder = null;}if (mOutput != null) {try {mOutput.flush();mOutput.close();} catch (IOException e) {e.printStackTrace();}mOutput = null;}}
几个需要注意的地方
1、编码线程初始化的地方，获取初始化所需的必要参数 2、编解码线程之间的同步，由于解码线程一般比编码线程快，所以pcm的队列数据同步显得比较重要，当然了这个消费者模式的基础，相信大家很容易理解 3、aac文件的保存，需要添加头纯净版MP3ToAAc（可以同时剪辑）所有代码
import android.media.MediaCodec;import android.media.MediaCodecInfo;import android.media.MediaExtractor;import android.media.MediaFormat;import android.media.MediaPlayer;import android.os.Build;import android.support.annotation.RequiresApi;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 java.util.Queue;import java.util.concurrent.LinkedBlockingQueue;/*** 音频转换成为aac编码** @author jake* @since /8/3 下午4:28*/@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)public class TransAacHandlerPure {private String srcFile;private String outFile;private long rangeStart = -1;private long rangeEnd = -1;private OnProgressListener listener;public TransAacHandlerPure(String srcFile, String outFile) {this(srcFile, outFile, null);}public TransAacHandlerPure(String srcFile, String outFile, OnProgressListener listener) {this(srcFile, outFile, -1, -1, listener);}public TransAacHandlerPure(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, IDataObtain {private static final long TIME_OUT = 5000;private Queue<byte[]> mRawQueue;private MediaExtractor extractor;private boolean isFinish = false;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;mRawQueue = new LinkedBlockingQueue<>();}private void pushAvFrame(byte[] frame) {if (frame != null) {int len = mRawQueue.size();while (len > 10) {try {Thread.sleep(10);} catch (InterruptedException e) {e.printStackTrace();}len = mRawQueue.size();}synchronized (mRawQueue) {mRawQueue.offer(frame);}}}@Overridepublic void run() {TransAacHandlerPure.logMsg("decodec run");if (listener != null) {listener.onStart();}boolean isPrepare = false;try {prepare();isPrepare = true;} catch (IOException e) {e.printStackTrace();}TransAacHandlerPure.logMsg("decodec isPrepare " + isPrepare);if (isPrepare) {decode();}release();if (!isPrepare && listener != null) {listener.onFail();}isFinish = true;}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();TransAacHandlerPure.logMsg("New decode codec start:" + format.toString());break;}}createFile(outFile + ".pcm", true);//测试 输出pcm格式mOutput = new DataOutputStream(new FileOutputStream(outFile + ".pcm"));}long last;private void decode() {ByteBuffer[] inputBuffers = codec.getInputBuffers();ByteBuffer[] outputBuffers = codec.getOutputBuffers();MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();TransAacHandlerPure.logMsg("loopDecode start");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;TransAacHandlerPure.logMsg("loopDecode readSampleData end sampleSize " + sampleSize + " buffer.capacity()=" + buffer.capacity());TransAacHandlerPure.logMsg("loopDecode readSampleData end timestamp" + timestamp);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);//TransAacHandlerPure.logMsg(" switch (outIndex)");switch (outIndex) {case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:outputBuffers = codec.getOutputBuffers();TransAacHandlerPure.logMsg("dequeueOutputBuffer INFO_OUTPUT_BUFFERS_CHANGED!");break;case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:MediaFormat mf = codec.getOutputFormat();//开始编码线程EncodeTask encodeTask = new EncodeTask(outFile, this, listener);int sampleRate = mf.getInteger(MediaFormat.KEY_SAMPLE_RATE);int pcmEncoding = mf.getInteger(MediaFormat.KEY_PCM_ENCODING);int channelCount = mf.getInteger(MediaFormat.KEY_CHANNEL_COUNT);encodeTask.setAudioParams(sampleRate, pcmEncoding, channelCount);new Thread(encodeTask).start();TransAacHandlerPure.logMsg("New format " + mf.toString());break;case MediaCodec.INFO_TRY_AGAIN_LATER:TransAacHandlerPure.logMsg("dequeueOutputBuffer timed out!");break;default:if (last == 0) {last = System.currentTimeMillis();}long now = System.currentTimeMillis();TransAacHandlerPure.logMsg("解码时间：" + (now - last) + " info.size " + info.size);last = now;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();}pushAvFrame(outData);if (listener != null) {listener.onProgress(rangeEnd > 0 ? (int) rangeEnd : duration, rangeStart > 0 ? (int) (timestamp - rangeStart) : (int) timestamp);}break;}// All decoded frames have been rendered, we can stop playing nowif ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {TransAacHandlerPure.logMsg("OutputBuffer BUFFER_FLAG_END_OF_STREAM");break;}}}@Overridepublic byte[] getRawFrame() {int len = mRawQueue.size();if (len > 0) {synchronized (mRawQueue) {return mRawQueue.poll();}}return null;}@Overridepublic boolean isFinish() {return isFinish;}}private static void logMsg(String msg) {Log.d(TransAacHandlerPure.class.getSimpleName(), msg);}private static class EncodeTask implements Runnable {private static final long TIME_OUT = 5000;private IDataObtain obtain;private String outFile;private MediaCodec encoder;private OutputStream mOutput;private OnProgressListener listener;private long last;private int sampleRate;private int pcmEncoding;private int channelCount;public EncodeTask(String outFile, IDataObtain obtain, OnProgressListener listener) {this.obtain = obtain;this.outFile = outFile;this.listener = listener;}public void setAudioParams(int sampleRate, int pcmEncoding, int channelCount) {this.sampleRate = sampleRate;this.pcmEncoding = pcmEncoding;this.channelCount = channelCount;}@Overridepublic void run() {boolean isPrepare = false;try {prepare();isPrepare = true;} catch (IOException e) {e.printStackTrace();}if (isPrepare && obtain != null) {encode();}release();if (listener != null) {if (isPrepare) {listener.onSuccess();} else {listener.onFail();}}}private void release() {if (encoder != null) {encoder.stop();encoder.release();encoder = null;}if (mOutput != null) {try {mOutput.flush();mOutput.close();} catch (IOException e) {e.printStackTrace();}mOutput = null;}}private void encode() {boolean isFinish = false;while (true) {if (!isFinish) {byte[] rawData = obtain.getRawFrame();if (rawData == null) {if (obtain.isFinish()) {isFinish = true;int inIndex = encoder.dequeueInputBuffer(TIME_OUT);encoder.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);} else {try {Thread.sleep(10);} catch (InterruptedException e) {e.printStackTrace();}}continue;}ByteBuffer[] inputBuffers = encoder.getInputBuffers();int inIndex = encoder.dequeueInputBuffer(TIME_OUT);if (inIndex >= 0) {ByteBuffer inputBuffer = inputBuffers[inIndex];inputBuffer.clear();inputBuffer.put(rawData);encoder.queueInputBuffer(inIndex, 0, rawData.length, System.nanoTime(), 0);}}ByteBuffer[] outputBuffers = encoder.getOutputBuffers();MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();int outIndex = encoder.dequeueOutputBuffer(info, TIME_OUT);if (outIndex >= 0) {if (last == 0) {last = System.currentTimeMillis();}long now = System.currentTimeMillis();TransAacHandlerPure.logMsg("编码码时间：" + (now - last) + " info.size " + info.size);last = now;while (outIndex >= 0) {ByteBuffer outputBuffer = outputBuffers[outIndex];int len = info.size + 7;byte[] outData = new byte[len];addADTStoPacket(outData, len);outputBuffer.get(outData, 7, info.size);encoder.releaseOutputBuffer(outIndex, false);try {mOutput.write(outData);} catch (Exception e) {e.printStackTrace();} catch (Error e) {e.printStackTrace();}outIndex = encoder.dequeueOutputBuffer(info, TIME_OUT);}}if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {VLog.d("encode OutputBuffer BUFFER_FLAG_END_OF_STREAM");break;}}}/*** 给编码出的aac裸流添加adts头字段** @param packet 要空出前7个字节，否则会搞乱数据* @param packetLen*/private void addADTStoPacket(byte[] packet, int packetLen) {int profile = 2; //AAC LCint freqIdx = 4; //44.1KHzint chanCfg = 2; //CPEpacket[0] = (byte) 0xFF;packet[1] = (byte) 0xF9;packet[2] = (byte) (((profile - 1) << 6) + (freqIdx << 2) + (chanCfg >> 2));packet[3] = (byte) (((chanCfg & 3) << 6) + (packetLen >> 11));packet[4] = (byte) ((packetLen & 0x7FF) >> 3);packet[5] = (byte) (((packetLen & 7) << 5) + 0x1F);packet[6] = (byte) 0xFC;}private void prepare() throws IOException {String mime = MediaFormat.MIMETYPE_AUDIO_AAC;encoder = MediaCodec.createEncoderByType(mime);MediaFormat format = MediaFormat.createAudioFormat(mime, sampleRate, channelCount);format.setInteger(MediaFormat.KEY_BIT_RATE, 96000);format.setInteger(MediaFormat.KEY_PCM_ENCODING, pcmEncoding);format.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, 20 * 1024);format.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);logMsg(" New " + format.toString());encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);encoder.start();createFile(outFile, true);mOutput = new DataOutputStream(new FileOutputStream(outFile));}}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 IDataObtain {byte[] getRawFrame();boolean isFinish();}public static interface OnProgressListener {void onStart();void onProgress(int max, int progress);void onSuccess();void onFail();}}
关于音频裁剪比较简单，如果相同格式不需要转码，直接用MediaExtractor读取相关片段后直接写入即可，这样效率比较高。关于这个转码算法的效率还是比较低，主要原因是编码比较慢，虽然多线程解决了部分问题，但是效率还是比较慢，大家有兴趣可以提出修改意见，咱们一起优化一下这个算法！
由于准备匆忙，很多知识点都没有跟大家说清楚，望大家见谅！希望代码写得不是很乱，大家能看得懂，有不懂的地方，欢迎跟我沟通！
