Extreme camera lag on Nexus 4

问题:

Using the following very simple camera preview activity (from a google example found here), the Nexus 4 camera is noticeably slower that the device's standard camera application:

public class LiveCameraActivity extends Activity implements TextureView.SurfaceTextureListener {
      private Camera mCamera;
      private TextureView mTextureView;

      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);

          mTextureView = new TextureView(this);
          mTextureView.setSurfaceTextureListener(this);

          setContentView(mTextureView);
      }

      public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
          mCamera = Camera.open();

          try {
              mCamera.setPreviewTexture(surface);
              mCamera.startPreview();
          } catch (IOException ioe) {
              // Something bad happened
          }
      }

      public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
          // Ignored, Camera does all the work for us
      }

      public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
          mCamera.stopPreview();
          mCamera.release();
          return true;
      }

      public void onSurfaceTextureUpdated(SurfaceTexture surface) {
          // Invoked every time there's a new Camera preview frame
      }
  }

I have been having issues with my application's camera speed on the Nexus 4, but I see this problem on no other devices. I was concerned that this was a Jelly Bean 4.2 difference, but Galaxy Nexus phones running JB4.2 work as normal with no lag. I realize this example code uses a TextureView, but other phones do not experience lag with this example.

Any help would be greatly appreciated.

回答1:

I have found that the preview frame rate can be increased to a normal rate by setting the recording hint to true, but this severely decreases camera performance especially in medium to low light situations with regard to color saturation and contrast (I am shocked at the quality of the front facing camera given that this is Google's latest and greatest attempt to compete with the iPhone 5 and her quality cameras... can't wait for the X Phone).

This is not a solution to the problem, but it is something of a band-aid for developers looking to avoid shocking frame rates.

回答2:

If you set the picture-size to 3264x2448, this will fix it. Even if you don't ever take a picture the picture-size is important because ZSL is enabled by default. The default picture size is 640x480 and this causes the slow preview frame rate. Disabling ZSL makes the preview even faster which is why setting the recording hit to true helps, enabling HDR does the same thing.