玻璃相机预览显示乱码

我正在尝试在Google Glass中显示实时相机预览.

我正在使用所有相机默认设置(并且还尝试使用一些不同的图像格式;理想情况下,我可以使用其中一种YUV格式),但显示屏中显示的图像是乱码,如下所示:

布局很简单:

这是活动代码:

public class ScanActivity extends Activity {
    private static final String kTag = ScanActivity.class.getSimpleName();
    private TextureView mVideoCaptureView = null;
    private Camera mCamera = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan);
        setTitle(R.string.title_scan);

        mVideoCaptureView = (TextureView) findViewById(R.id.scan_preview);
        mVideoCaptureView.setKeepScreenOn(true);
        mVideoCaptureView.setSurfaceTextureListener(new VideoCaptureTextureListener());
    }

    @Override
    protected void onPause() {
        super.onPause();
        stopVideo();
    }

    @Override
    protected void onResume() {
        super.onResume();
        startVideo();
    }

    private void startVideo() {
        if (mCamera != null) {
            mCamera.release();
        }
        mCamera = Camera.open();
        if (null != mVideoCaptureView) {
            try {
                mCamera.setPreviewTexture(mVideoCaptureView.getSurfaceTexture());
            } catch (IOException e) {
                Log.e(kTag, "Error setting preview texture", e);
                return;
            }
        }
        mCamera.startPreview();
    }

    private void stopVideo() {
        if (null == mCamera)
            return;
        try {
            mCamera.stopPreview();
            mCamera.setPreviewDisplay(null);
            mCamera.setPreviewTexture(null);
            mCamera.release();
        } catch (IOException e) {
            Log.w(kTag, e);
        }
        mCamera = null;
    }

    private final class VideoCaptureTextureListener implements TextureView.SurfaceTextureListener {

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
            stopVideo();
            return true;
        }

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
            startVideo();
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surface) {
        }
    }
}

你知道为什么这个完全没有操作的相机预览没有正确显示吗？