Android Wear开发之录一段可以被百度媒体云识别的语音文件

感谢http://blog.sina.com.cn/s/blog_4c070656010127tn.html提供的AudioRecoder类的介绍。

原程序：

public class myAudioRecorder extends Activity {
    private boolean isRecording = false ;
    private Object tmp = new Object() ;
   
   
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        Button start = (Button)findViewById(R.id.start_bt) ;
        start.setOnClickListener(new OnClickListener()
        {
 
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                Thread thread = new Thread(new Runnable() {
                    public void run() {
                      record();
                    }    
                  });
                  thread.start();
                  findViewById(R.id.start_bt).setEnabled(false) ;
                  findViewById(R.id.end_bt).setEnabled(true) ;
            }
         
        }) ;
       
        Button play = (Button)findViewById(R.id.play_bt) ;
        play.setOnClickListener(new OnClickListener(){
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                play();
            }
         
        }) ;
       
        Button stop = (Button)findViewById(R.id.end_bt) ;
        stop.setEnabled(false) ;
        stop.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                isRecording = false ;
                findViewById(R.id.start_bt).setEnabled(true) ;
                findViewById(R.id.end_bt).setEnabled(false) ;
            }
         
        }) ;
       
    }
 
    public void play() {
      // Get the file we want to playback.
      File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/reverseme.pcm");
      // Get the length of the audio stored in the file (16 bit so 2 bytes per short)
      // and create a short array to store the recorded audio.
      int musicLength = (int)(file.length()/2);
      short[] music = new short[musicLength];
 
 
      try {
        // Create a DataInputStream to read the audio data back from the saved file.
        InputStream is = new FileInputStream(file);
        BufferedInputStream bis = new BufferedInputStream(is);
        DataInputStream dis = new DataInputStream(bis);
         
        // Read the file into the music array.
        int i = 0;
        while (dis.available() > 0) {
          music[i] = dis.readShort();
          i++;
        }
 
 
        // Close the input streams.
        dis.close();    
 
 
        // Create a new AudioTrack object using the same parameters as the AudioRecord
        // object used to create the file.
        AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                                               11025,
                                               AudioFormat.CHANNEL_CONFIGURATION_MONO,
                                               AudioFormat.ENCODING_PCM_16BIT,
                                               musicLength*2,
                                               AudioTrack.MODE_STREAM);
        // Start playback
        audioTrack.play();
     
        // Write the music buffer to the AudioTrack object
        audioTrack.write(music, 0, musicLength);
 
        audioTrack.stop() ;
 
      } catch (Throwable t) {
        Log.e("AudioTrack","Playback Failed");
      }
    }
 
    public void record() {
      int frequency = 11025;
      int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
      int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
      File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/reverseme.pcm");
      
      // Delete any previous recording.
      if (file.exists())
        file.delete();
 
 
      // Create the new file.
      try {
        file.createNewFile();
      } catch (IOException e) {
        throw new IllegalStateException("Failed to create " + file.toString());
      }
      
      try {
        // Create a DataOuputStream to write the audio data into the saved file.
        OutputStream os = new FileOutputStream(file);
        BufferedOutputStream bos = new BufferedOutputStream(os);
        DataOutputStream dos = new DataOutputStream(bos);
        
        // Create a new AudioRecord object to record the audio.
        int bufferSize = AudioRecord.getMinBufferSize(frequency, channelConfiguration,  audioEncoding);
        AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,
                                                  frequency, channelConfiguration,
                                                  audioEncoding, bufferSize);
      
        short[] buffer = new short[bufferSize];  
        audioRecord.startRecording();
 
        isRecording = true ;
        while (isRecording) {
          int bufferReadResult = audioRecord.read(buffer, 0, bufferSize);
          for (int i = 0; i < bufferReadResult; i++)
            dos.writeShort(buffer[i]);
        }
 
 
        audioRecord.stop();
        dos.close();
      
      } catch (Throwable t) {
        Log.e("AudioRecord","Recording Failed");
      }
    }
}

由于百度媒体云的语音识别只支持小端字节序的音频，而使用上面的方法输出的文件是大端字节序，所以要对record函数进行一下修改。(单声道的API已经被划横线，下面使用了新的单声道API,相关参数也已经调为百度提供的DEMO使用的参数)：

    public void record() {
        int frequency = 8000;
        int channelConfiguration = AudioFormat.CHANNEL_IN_DEFAULT;
        int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
        File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/order.pcm");

        // Delete any previous recording.
        if (file.exists())
            file.delete();


        // Create the new file.
        try {
            file.createNewFile();
        } catch (IOException e) {
            throw new IllegalStateException("Failed to create " + file.toString());
        }

        try {
            // Create a DataOuputStream to write the audio data into the saved file.
            OutputStream os = new FileOutputStream(file);
            BufferedOutputStream bos = new BufferedOutputStream(os);
            DataOutputStream dos = new DataOutputStream(bos);

            // Create a new AudioRecord object to record the audio.
            int bufferSize = AudioRecord.getMinBufferSize(frequency, channelConfiguration, audioEncoding);
            AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,
                    frequency, channelConfiguration,
                    audioEncoding, bufferSize);

            short[] buffer = new short[bufferSize];
            byte[] bt = new byte[2];
            audioRecord.startRecording();

            isRecording = true;
            while (isRecording) {
                int bufferReadResult = audioRecord.read(buffer, 0, bufferSize);
                for (int i = 0; i < bufferReadResult; i++) {
                    bt[1] = (byte) (buffer[i] >> 8);
                    bt[0] = (byte) (buffer[i] >> 0);
                    dos.writeShort((short) (((bt[0] << 8) | bt[1] & 0xff)));
                }
            }
            for (int i = 0; i <= 100; i++) {
                dos.writeShort(0x00);
            }

            audioRecord.stop();
            dos.flush();
            dos.close();
            
        } catch (Throwable t) {
            Log.e("AudioRecord", "Recording Failed");
        }
    }