android开发，静音录制视频，在一般清晰度的前提下保证文件大小越小越好

public void startRecord() {
        mediarecorder = new MediaRecorder();// 创建mediarecorder对象
        mCamera = getCameraInstance();
        Parameters parameters = mCamera.getParameters(); 
        mCamera.autoFocus(null);
        // 解锁camera
        mCamera.setDisplayOrientation(90);
        mCamera.unlock();
        mediarecorder.setCamera(mCamera);

        
        List<Size> supportedPreviewSizes = parameters.getSupportedPreviewSizes(); 
        for(int i=0;i<supportedPreviewSizes.size();i++)
        {
            Log.v("startRecord", "width="+supportedPreviewSizes.get(i).width+";height="+supportedPreviewSizes.get(i).height);
        }
        // 设置录制视频源为Camera(相机)
//        mediarecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mediarecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        // 设置录制文件质量，格式，分辨率之类，这个全部包括了
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_480P));  //7.43M  10frame
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_1080P));   //70.94M  10frame
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_CIF));  // 2.6M  5frame/10frame
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_QCIF));  //0.76M   30frame  模糊
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_QVGA));  //2.1M 
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_TIME_LAPSE_CIF));  //不支持
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_LOW));  //766KB  还行  比QUALITY_QCIF好
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_TIME_LAPSE_LOW));  //1M 质量类似LOW
//        mediarecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_TIME_LAPSE_480P));  //480p效果
//        mediarecorder.setAudioEncoder(MediaRecorder.AudioEncoder.);
//        mediarecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
        
//        boolean isSupQUALITY_TIME_LAPSE_CIF = CamcorderProfile.hasProfile(CamcorderProfile.QUALITY_TIME_LAPSE_CIF);
//        boolean isSupQUALITY_LOW = CamcorderProfile.hasProfile(CamcorderProfile.QUALITY_LOW);
//        Log.v("startRecord", "isSupQUALITY_TIME_LAPSE_CIF="+isSupQUALITY_TIME_LAPSE_CIF+";isSupQUALITY_LOW="+isSupQUALITY_LOW);
//        
//        mediarecorder.setVideoFrameRate(30);
        
        
        
      //start实现录像静音
        mediarecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
//        mediarecorder.setVideoSize(640,480);
        mediarecorder.setVideoSize(1280,720);
        //设置编码比特率,不设置会使视频图像模糊
//        mediarecorder.setVideoEncodingBitRate(5*1024*1024);  //清晰     512*1024(不清楚)
        mediarecorder.setVideoEncodingBitRate(900*1024); //较为清晰，且文件大小为3.26M(30秒)
        mediarecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);  //H263的貌似有点不清晰
//        mediarecorder.setVideoFrameRate(10);  //设置无效
        //end
        
        mediarecorder.setPreviewDisplay(surfaceHolder.getSurface());

        // 设置视频文件输出的路径
        mediarecorder.setOutputFile(Environment.getExternalStorageDirectory().getAbsolutePath() + "/data/data/"+System.currentTimeMillis()+".mp4");
        try {
            // 准备录制
            mediarecorder.prepare();
            // 开始录制
            mediarecorder.start();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }