安卓拍摄视频如何全屏适配？

Question

1，最近遇到个问题，用camera录制的视频，在拍摄预览过程中是全屏的，到文件管理器中播放就不是的了，会比拍摄时看到的宽一些，困扰了很久，不知道怎么解决，恳请大佬指点一下？

2，代码：

public class MainActivity extends AppCompatActivity {

    private SurfaceView surfaceview;
    private MediaRecorder mr;
    private Button bt_start;
    private Button bt_stop;
    private boolean isRecording = false;
    private Camera mCamera;
    private int width;
    private int height;
    private Camera.Size previewSize;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        surfaceview = (SurfaceView) findViewById(R.id.surfaceview);

        bt_start = (Button) findViewById(R.id.bt_start);
        bt_stop = (Button) findViewById(R.id.bt_stop);
        WindowManager wm = (WindowManager) this
                .getSystemService(Context.WINDOW_SERVICE);
        width = wm.getDefaultDisplay().getWidth();
        height = wm.getDefaultDisplay().getHeight();
        SurfaceHolder holder = surfaceview.getHolder();
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        holder.setFixedSize(width, height);
        surfaceview.setKeepScreenOn(true);
    }

    public void start(View v){
        //实际的权限申请不应该这么写
        new RxPermissions(this)
                .request(Manifest.permission.CAMERA,
                        Manifest.permission.CAPTURE_SECURE_VIDEO_OUTPUT,
                        Manifest.permission.RECORD_AUDIO,
                        Manifest.permission.READ_EXTERNAL_STORAGE,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE)
                .subscribe(new Consumer<Boolean>() {
                    @Override
                    public void accept(Boolean aBoolean) throws Exception {
                        if(aBoolean){
                            Toast.makeText(MainActivity.this,"已授权",Toast.LENGTH_SHORT).show();
                        }else {
                            Toast.makeText(MainActivity.this,"未授权",Toast.LENGTH_SHORT).show();
                        }
                    }
                });
        try {
            mCamera = Camera.open();
            Camera.Parameters parameters = mCamera.getParameters();
            mCamera.setDisplayOrientation(90);
            mCamera.setPreviewDisplay(surfaceview.getHolder());
            mCamera.startPreview();
            List<Camera.Size> mSupportedPreviewSizes = parameters.getSupportedPreviewSizes();

            if (mSupportedPreviewSizes != null) {
                previewSize = getOptimalPreviewSize(mSupportedPreviewSizes,
                        Math.max(width, height), Math.min(width, height));
            }
            Camera.Parameters mParams = mCamera.getParameters();
            mParams.setPreviewSize(previewSize.width, previewSize.height);
//            mCamera.setDisplayOrientation(90);
            List<String> focusModes = mParams.getSupportedFocusModes();
            if(focusModes.contains("continuous-video")){
                mParams.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
            }
            mCamera.setParameters(mParams);

            mCamera.unlock();

            mr = new MediaRecorder();
            mr.setCamera(mCamera);
            mr.reset();



            mr.setPreviewDisplay(surfaceview.getHolder().getSurface());
            mr.setVideoSource(MediaRecorder.VideoSource.CAMERA);// 视频源
            mr.setAudioSource(MediaRecorder.AudioSource.MIC);// 音频源
            mr.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);// 视频输出格式
            mr.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);// 音频格式
            mr.setVideoSize(previewSize.width,previewSize.height);
            mr.setVideoFrameRate(30);
            mr.setVideoEncodingBitRate(3*1024*1024);// 设置帧频率，然后就清晰了
            mr.setOrientationHint(90);// 输出旋转90度，保持竖屏录制
            mr.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);// 视频录制格式
            File file = new File(Environment.getExternalStorageDirectory(),"zz"+System.currentTimeMillis()+".mp4");
            mr.setOutputFile(file.getAbsolutePath());
            mr.setOnErrorListener(new MediaRecorder.OnErrorListener() {
                @Override
                public void onError(MediaRecorder mr, int what, int extra) {
                    isRecording = false;
                    mr.stop();
                    mr.release();
                    mr = null;
                    isRecording = false;
                    bt_start.setEnabled(true);
                    bt_stop.setEnabled(false);
                    Toast.makeText(MainActivity.this,"录制出错！",Toast.LENGTH_SHORT).show();
                }
            });
            //设置预览显示
            mr.setPreviewDisplay(surfaceview.getHolder().getSurface());
            mr.prepare();
            mr.start();
            bt_start.setEnabled(false);
            bt_stop.setEnabled(true);
            Toast.makeText(MainActivity.this,"录制开始！",Toast.LENGTH_SHORT).show();
        } catch (Exception e) {
            //TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public void stop(View v){
        mr.stop();
        bt_start.setEnabled(true);
        bt_stop.setEnabled(false);
    }

    @Override
    protected void onDestroy() {
        //TODO Auto-generated method stub
        super.onDestroy();

        if(mr!= null){
            mr.release();
            mr = null;
        }
    }

    public Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) w / h;
        if (sizes == null) {
            return null;
        }
        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;
        int targetHeight = h;
        for (Camera.Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }


}

3，图片：

拍摄图：
    

在文件夹中播放的图：
    

4，会看到实际上的图片会宽一些，应该怎么解决这个问题，想做成全屏的。

Answer 1

也就是预览和实际不相同，你获取屏幕的宽和高的方法可能存在一定的差距，我没记错的话这个数值和实际有所出入。
不过我自己也没尝试过是否因为这个原因，可以参考https://blog.csdn.net/gh86091...

看是否有所帮助

Answer 2

getOptimalPreviewSize 的第一个参数是硬件所支持的尺寸列表，后面长宽是你想要显示的UI尺寸。
所以预览的图片显示是经过修正的，并不是摄像头看到的实际尺寸。
个人想法
方案1.只是用完全匹配的尺寸，即UI尺寸和硬件尺寸相同比例的size （不太好，特别是低档机的硬件支持数少，会很模糊）
方案2.拿到拍摄后的图后修图。不直接用系统相机生成的图，用工具类裁剪后保存。