簡易版WoMic（二）

在閱讀這篇文章之前，最好可以看一下這篇文章WoMic虛擬麥克風技術剖析。
這篇文章介紹Womic的技術原理，因此這篇文章按照這個技術路線實現簡單的WoMic。

WoMic由三個部分進行介紹：
1.虛擬聲卡
2.PC端
3.Android 端

虛擬聲卡

Womic採用自己開發的虛擬聲卡，但是這裏我們採用開源的虛擬聲卡 Virtual Audio Cables，它是一款免費個人使用的虛擬聲卡，它在虛擬麥克風中主要作用就是輸入數據並從虛擬麥克中輸出聲音，應用就可以自由從虛擬聲卡中讀取數據。

自行從網站上下載並安裝，我相信這一點不會難到你，若是安裝有問題你回覆評論。

Android 端

Android端是用於錄製聲音的，也就是作爲麥克風。Android 採用的AudioTrack獲取聲音的pcm流，採用的是tcp方式進行傳輸pcm流，不瞭解網絡傳輸的可以參考這篇文章Android中socket(tcp|udp)，websocket基本使用。

設置AudioTrack 頻率，聲道，碼率等等，這些必須也pc端保持一致，不然出來的聲音會是噪音。

• 聲音採集
  下面是聲音採集類AudioTrackUtil.class:

public class AudioTrackUtil {
    AudioRecord mAudioRecord;

    private Integer mRecordBufferSize;
    private boolean mWhetherRecord;

    private void initMinBufferSize() {
        //獲取每一幀的字節流大小
        mRecordBufferSize = AudioRecord.getMinBufferSize(8000
                , AudioFormat.CHANNEL_IN_MONO
                , AudioFormat.ENCODING_PCM_8BIT);
    }

    public AudioTrackUtil() {
        initMinBufferSize();
        if (mAudioRecord == null) {
            mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC
                    , 8000
                    , AudioFormat.CHANNEL_IN_MONO
                    , AudioFormat.ENCODING_PCM_8BIT
                    , mRecordBufferSize);
        }
    }

    public void startRecord() {
        mWhetherRecord = true;
        new Thread(new Runnable() {
            @Override
            public void run() {
                mAudioRecord.startRecording();//開始錄製
                try {
                    byte[] bytes = new byte[mRecordBufferSize];
                    while (mWhetherRecord) {
                        mAudioRecord.read(bytes, 0, bytes.length);//讀取流
                        mIAudioCallBack.callBack(bytes);
                    }
                    Log.e("test", "run: 暫停錄製");
                    mAudioRecord.stop();//停止錄製
                } catch (Exception e) {
                    e.printStackTrace();
                    mWhetherRecord = false;
                    mAudioRecord.stop();
                }
            }
        }).start();
    }

    void stopRecord() {
        if (mAudioRecord != null) {
            mAudioRecord.stop();
            mAudioRecord.release();
        }
    }

    public IAudioCallBack mIAudioCallBack;

    public interface IAudioCallBack {
        void callBack(byte[] o);
    }

    public void setIAudioCallBackListener(IAudioCallBack audioCallBack) {
        mIAudioCallBack = audioCallBack;
    }
}

• 通過TCP方式發送pcm流
  通過Socket類，設置目標IP和Port，通過
  socket.getOutputStream().write(msg);
  socket.getOutputStream().flush();
  進行寫數據，併發送到服務端，這裏就是pc端。代碼如下：

public class MainActivity extends AppCompatActivity {
    private Button mBtnSendMessage;
    public Socket socket;
    private AudioTrackUtil mAudioTrackUtil;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mBtnSendMessage = findViewById(R.id.btn_start_send_message);
        mAudioTrackUtil = new AudioTrackUtil();
        final String ip = "192.168.40.57";//10.5.169.16服務端的IP地址;10.5.206.92
        final int port = 5678;//自己定義個端口號要與服務端匹配。

        startClient(ip, port);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED ||
                ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED ||
                ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.RECORD_AUDIO,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE,
                    Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
        }

        mBtnSendMessage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (socket == null) {
                    startClient(ip, port);
                }
                if (socket.isConnected()) {
                    mAudioTrackUtil.startRecord();
                    mAudioTrackUtil.setIAudioCallBackListener(new AudioTrackUtil.IAudioCallBack() {
                        @Override
                        public void callBack(byte[] o) {
                            sendTcpMessage(o);
                        }
                    });
                }
            }
        });

        findViewById(R.id.btn_stop_send_message).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (socket != null) {
                    try {
                        sendTcpMessage("我要結束了".getBytes());
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        mAudioTrackUtil.startRecord();
    }

    public void startClient(final String address, final int port) {
        if (address == null) {
            return;
        }
        if (socket == null) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        Log.i("tcp", "啓動客戶端");
                        socket = new Socket(address, port);
                        Log.i("tcp", "客戶端連接成功");

                        InputStream inputStream = socket.getInputStream();

                        byte[] buffer = new byte[1024];
                        int len = -1;
                        while ((len = inputStream.read(buffer)) != -1) {
                            String data = new String(buffer, 0, len);
                            Log.i("tcp", "收到服務器的數據-------------------:" + data);
                        }
                        Log.i("tcp", "客戶端斷開連接");

                    } catch (Exception EE) {
                        EE.printStackTrace();
                        Log.i("tcp", "客戶端無法連接服務器" + EE.getMessage());

                    } finally {
                        try {
                            if (socket != null) {
                                socket.close();
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        socket = null;
                    }
                }
            }).start();
        }
    }

    public void sendTcpMessage(final byte[] msg) {
        if (socket != null && socket.isConnected()) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        socket.getOutputStream().write(msg);
                        socket.getOutputStream().flush();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        try {
            if (socket != null) {
                socket.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        mAudioTrackUtil.stopRecord();
    }
   }

pc端

第一步，獲取虛擬聲卡，需要設置採樣頻率，樣本位數，聲道等，需要和Android的參數一致，不然是噪音。

public class AudioVirtualCableUtile {
    SourceDataLine auline = null;

    public AudioVirtualCableUtile() {
        AudioFormat.Encoding encoding = new AudioFormat.Encoding("PCM_SIGNED");
        AudioFormat format = new AudioFormat(encoding,
                8000,
                16,
                2,
                2,
                8000,
                true);//編碼格式，採樣率，每個樣本的位數，聲道，幀長（字節），幀數，是否按big-endian字節順序存儲

        DataLine.Info info = new DataLine.Info(SourceDataLine.class, format);

        try {
            Mixer.Info[] mixerInfos = AudioSystem.getMixerInfo();
            Mixer mixer = null;
            for (int i = 0; i < mixerInfos.length; i++) {
                System.out.println(mixerInfos[i]);
                if (mixerInfos[i].getName().equals("CABLE Input (VB-Audio Virtual Cable)")) {
                    mixer = AudioSystem.getMixer(mixerInfos[i]);
                    System.out.println("get successful");
                }
            }
            auline = (SourceDataLine) mixer.getLine(info);
            auline.open(format);
        } catch (LineUnavailableException e) {
            e.printStackTrace();
            return;
        } catch (Exception e) {
            e.printStackTrace();
            return;
        }
    }

    SourceDataLine getAudioLine() {
        return auline;
    }

第二步，獲取從Android過來的pcm流，並寫入到虛擬聲卡中。

private static ServerSocket mServerSocket;
    private static Socket mSocket;
    private static AudioVirtualCableUtile pcmUtile = new AudioVirtualCableUtile();

    public static void main(String args[]) {
        startServer();
    }


    static void startServer() {
        if (mServerSocket == null) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        mServerSocket = new ServerSocket(5678);
                        System.out.println("tcp connecting");
                        mSocket = mServerSocket.accept();
                        System.out.println("tcp connected");
                        InputStream inputStream = mSocket.getInputStream();
                        byte[] buffer = new byte[1024];
                        int len = -1;
//
                        pcmUtile.getAudioLine().start();
                        while ((len = inputStream.read(buffer)) != -1) {
                            pcmUtile.getAudioLine().write(buffer, 0, len);//寫入到虛擬聲卡中
                            System.out.println("----" + System.currentTimeMillis());
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                        try {
                            mSocket.close();
                            mServerSocket.close();
                        } catch (IOException e1) {
                            e1.printStackTrace();
                        }
                    }
                }
            }).start();
        }
    }
}

運行pc和Android代碼，你會發現麥克有音量變化

到此代碼基本已經完成，還需要持續優化，本篇文章中的代碼純demo，沒有過多考慮，只要功能滿足即可。

備註：
需要手動切換虛擬聲卡。需要先啓動pc端，在啓動Android，因爲pc端爲服務端。