java - 如何禁用 Android Camera2 API 中的所有自动功能

Question

我正在尝试禁用 Google Camera2Basic 中的自动曝光、自动对焦和自动白平衡功能样本。这是我的代码:

private void disableAutomatics() {
    try {
        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_MODE, CaptureRequest.CONTROL_MODE_OFF);
        mPreviewRequestBuilder.set(CaptureRequest.CONTROL_VIDEO_STABILIZATION_MODE, CaptureRequest.CONTROL_VIDEO_STABILIZATION_MODE_OFF);
        mPreviewRequestBuilder.set(CaptureRequest.LENS_OPTICAL_STABILIZATION_MODE, CaptureRequest.LENS_OPTICAL_STABILIZATION_MODE_OFF);
        mPreviewRequestBuilder.set(CaptureRequest.LENS_FOCUS_DISTANCE, .2f);
        mPreviewRequestBuilder.set(CaptureRequest.SENSOR_EXPOSURE_TIME, 1000000L);

        mPreviewRequest = mPreviewRequestBuilder.build();
        // Set new repeating request with our changed one
        mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

问题是我不知道将该方法放置在 Camera2BasicFragment.java 中的何处。

任何帮助将不胜感激。

Answer 1

您可能需要在两个地方进行这些设置:

• 如果您想在预览开始之前执行此操作，则更好的位置应位于 createCameraPreviewSession() void 中的重写方法 onConfigured 内(行Google 的 Camera2BasicFragment 示例中提供的 Camera2Basic 文件中的 696:

  private void createCameraPreviewSession() {
      try {
          SurfaceTexture texture = mTextureView.getSurfaceTexture();
          assert texture != null;
  
          // We configure the size of default buffer to be the size of camera preview we want.
          texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
  
          // This is the output Surface we need to start preview.
          Surface surface = new Surface(texture);
  
          // We set up a CaptureRequest.Builder with the output Surface.
          mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
          mPreviewRequestBuilder.addTarget(surface);
  
          // Here, we create a CameraCaptureSession for camera preview.
          mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
              new CameraCaptureSession.StateCallback() {
  
                  @Override
                  public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                      // The camera is already closed
                      if (null == mCameraDevice) {
                          return;
                      }
  
                      // When the session is ready, we start displaying the preview.
                      mCaptureSession = cameraCaptureSession;
                      try {
  
  
                          //Place here your custom camera settings
  
  
                          // Start displaying the camera preview.
                          mPreviewRequest = mPreviewRequestBuilder.build();
                          mCaptureSession.setRepeatingRequest(mPreviewRequest,
                                  mCaptureCallback, mBackgroundHandler);
                      } catch (CameraAccessException e) {
                          e.printStackTrace();
                      }
                  }
  
                  @Override
                  public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                      showToast("Failed");
                  }
              }, null
          );
      } catch (CameraAccessException e) {
          e.printStackTrace();
      }
  }
  

• 如果您想在预览开始后并在运行时进行设置，只需从 UI 或其他任何地方调用 disableAutomatics() 即可正常工作。

请注意，您不必通过调用 CaptureSession.close() 方法来关闭旧的 CaptureSession，如 this other question 的回答中所述。因为新的取代了旧的。

---

另一方面，我不确定是否像您在问题中那样手动设置曝光时间值:

mPreviewRequestBuilder.set(CaptureRequest.SENSOR_EXPOSURE_TIME, 1000000L);

因为您可能会在不同设备上得到不同的意外结果。据我所知，通常不鼓励这样做，最好让相机自行调整，然后调用 AE(自动曝光)锁定:

mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_LOCK, true);

您可以查看CONTROL_AE_LOCK引用here .

但是如果您的代码需要固定的曝光时间，那么它应该可以工作。