Camera2 API AutoFocus with Samsung S5

问题:

I'm working with the new Camera2 API on a Samsung S5. The supported hardware level this device is reporting is LEGACY, which is fine.

However, I cannot seem to be able to auto-focus on this device. The request to trigger auto-focus looks like this:

previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO); previewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CaptureRequest.CONTROL_AF_TRIGGER_START); state = STATE_PREVIEW; try {   captureSession.setRepeatingRequest(previewRequestBuilder.build(), captureCallback, backgroundHandler); } catch (CameraAccessException e) {   e.printStackTrace(); } 

After the request is sent, the result of the request is always CONTROL_AF_STATE_ACTIVE_SCAN and occasionally CONTROL_AF_STATE_NOT_FOCUSED_LOCKED.

The strange thing is that, when the state is CONTROL_AF_STATE_NOT_FOCUSED_LOCKED, the auto-focus goes back into the CONTROL_AF_STATE_ACTIVE_SCAN state for a while and then back to CONTROL_AF_STATE_NOT_FOCUSED_LOCKED, resulting in a infinite focus loop. According to the docs, when state is CONTROL_AF_STATE_NOT_FOCUSED_LOCKED...

The lens will remain stationary until the AF mode (android.control.afMode) is changed or a new AF trigger is sent to the camera device (android.control.afTrigger).

I'm wondering if this discrepancy is because of the fact that the hardware level is LEGACY and that I should go back to using the deprecated Camera API, but that seems crazy for such a prevalent feature such as auto focus.

Is there any reccomendations how how to treat devices that are reporting LEGACY?

回答1:

I branched form google's Camera2Basic example and changed it to use CaptureRequest.CONTROL_AF_MODE_AUTO instead of CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE

You can take the project from git and test it - https://github.com/pinhassi/android-Camera2Basic

Or just add this to Camera2BasicFragment:

private static final long LOCK_FOCUS_DELAY_ON_FOCUSED = 5000; private static final long LOCK_FOCUS_DELAY_ON_UNFOCUSED = 1000;  private Integer mLastAfState = null; private Handler mUiHandler = new Handler(); // UI handler private Runnable mLockAutoFocusRunnable = new Runnable() {      @Override     public void run() {         lockAutoFocus();     } };   public void lockAutoFocus() {     try {         // This is how to tell the camera to lock focus.         mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);         CaptureRequest captureRequest = mPreviewRequestBuilder.build();         mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, null); // prevent CONTROL_AF_TRIGGER_START from calling over and over again         mCaptureSession.capture(captureRequest, mCaptureCallback, mBackgroundHandler);     } catch (CameraAccessException e) {         e.printStackTrace();     } }   /**  *  * @return  */ private float getMinimumFocusDistance() {     if (mCameraId == null)         return 0;      Float minimumLens = null;     try {         CameraManager manager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);         CameraCharacteristics c = manager.getCameraCharacteristics(mCameraId);         minimumLens = c.get(CameraCharacteristics.LENS_INFO_MINIMUM_FOCUS_DISTANCE);     } catch (Exception e) {         Log.e(TAG, "isHardwareLevelSupported Error", e);     }     if (minimumLens != null)         return minimumLens;     return 0; }  /**  *  * @return  */ private boolean isAutoFocusSupported() {     return  isHardwareLevelSupported(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY) || getMinimumFocusDistance() > 0; }  // Returns true if the device supports the required hardware level, or better. @TargetApi(Build.VERSION_CODES.LOLLIPOP) private boolean isHardwareLevelSupported(int requiredLevel) {     boolean res = false;     if (mCameraId == null)         return res;     try {         CameraManager manager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);         CameraCharacteristics cameraCharacteristics = manager.getCameraCharacteristics(mCameraId);          int deviceLevel = cameraCharacteristics.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);         switch (deviceLevel) {             case CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_3:                 Log.d(TAG, "Camera support level: INFO_SUPPORTED_HARDWARE_LEVEL_3");                 break;             case CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_FULL:                 Log.d(TAG, "Camera support level: INFO_SUPPORTED_HARDWARE_LEVEL_FULL");                 break;             case CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY:                 Log.d(TAG, "Camera support level: INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY");                 break;             case CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED:                 Log.d(TAG, "Camera support level: INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED");                 break;             default:                 Log.d(TAG, "Unknown INFO_SUPPORTED_HARDWARE_LEVEL: " + deviceLevel);                 break;         }           if (deviceLevel == CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY) {             res = requiredLevel == deviceLevel;         } else {             // deviceLevel is not LEGACY, can use numerical sort             res = requiredLevel <= deviceLevel;         }      } catch (Exception e) {         Log.e(TAG, "isHardwareLevelSupported Error", e);     }     return res; } 

Then, add to STATE_PREVIEW block:

        case STATE_PREVIEW: {              // We have nothing to do when the camera preview is working normally.             // TODO: handle auto focus             Integer afState = result.get(CaptureResult.CONTROL_AF_STATE);             if (afState != null && !afState.equals(mLastAfState)) {                 switch (afState) {                     case CaptureResult.CONTROL_AF_STATE_INACTIVE:                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_INACTIVE");                         lockAutoFocus();                         break;                     case CaptureResult.CONTROL_AF_STATE_ACTIVE_SCAN:                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_ACTIVE_SCAN");                         break;                     case CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED:                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED");                         mUiHandler.removeCallbacks(mLockAutoFocusRunnable);                         mUiHandler.postDelayed(mLockAutoFocusRunnable, LOCK_FOCUS_DELAY_ON_FOCUSED);                         break;                     case CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED:                         mUiHandler.removeCallbacks(mLockAutoFocusRunnable);                         mUiHandler.postDelayed(mLockAutoFocusRunnable, LOCK_FOCUS_DELAY_ON_UNFOCUSED);                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED");                         break;                     case CaptureResult.CONTROL_AF_STATE_PASSIVE_UNFOCUSED:                         mUiHandler.removeCallbacks(mLockAutoFocusRunnable);                         //mUiHandler.postDelayed(mLockAutoFocusRunnable, LOCK_FOCUS_DELAY_ON_UNFOCUSED);                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_PASSIVE_UNFOCUSED");                         break;                     case CaptureResult.CONTROL_AF_STATE_PASSIVE_SCAN:                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_PASSIVE_SCAN");                         break;                     case CaptureResult.CONTROL_AF_STATE_PASSIVE_FOCUSED:                         mUiHandler.removeCallbacks(mLockAutoFocusRunnable);                         //mUiHandler.postDelayed(mLockAutoFocusRunnable, LOCK_FOCUS_DELAY_ON_FOCUSED);                         Log.d(TAG, "CaptureResult.CONTROL_AF_STATE_PASSIVE_FOCUSED");                         break;                 }             }             mLastAfState = afState;             break;         } 

And replace all occurrences of:

mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,                                             CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE); 

With:

if (isAutoFocusSupported())                                 mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,                                         CaptureRequest.CONTROL_AF_MODE_AUTO);                             else                                 mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,                                         CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE); 

回答2:

I think the issue is with your setRepeatingRequest. As far as I know, CaptureRequest.CONTROL_AF_MODE_AUTO should only cause an autofocus to occur once, but setRepeatingRequest will send continuous requests. Try using capture instead:

previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO); previewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CaptureRequest.CONTROL_AF_TRIGGER_START);  state = STATE_PREVIEW;  try { mCaptureSession.capture(mPreviewRequestBuilder.build(), mPreCaptureCallback, mBackgroundHandler); } catch (Exception e) {e.printStackTrace();} 

回答3:

I experience the same issue with a Galaxy Note 4 running Android 5.1.1 - while the same code works fine on a variety of other Android devices. There have been reports of similar issues with Galaxy-S4/S5/S6.

http://developer.samsung.com/forum/board/thread/view.do?boardName=SDK&messageId=289824&startId=zzzzz~ https://www.youtube.com/watch?v=lnMoYZwVaFM

So to anwer you question: This is most likely a bug in Samsung's implementation of the Camera-2 implementation - which seems to be of very low quality, unfourtunately.

回答4:

The Samsung S5 with autofocus returned INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY, which means it does not support Camera2 api.

I have the below filter for using camera in my application.

if (Build.VERSION.SDK_INT >= 21 && isDeviceCompatibleOfCamera2()) {  // Use camera2 } else {  // Use old camera }  @TargetApi(Build.VERSION_CODES.LOLLIPOP)  public boolean isDeviceCompatibleOfCamera2() {  try {     CameraManager manager = (CameraManager) getActivity().getSystemService(Context.CAMERA_SERVICE);     String backCameraId = manager.getCameraIdList()[0];     CameraCharacteristics backCameraInfo = manager.getCameraCharacteristics(backCameraId);      int level = backCameraInfo.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);     return level == CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_FULL;      } catch (CameraAccessException e) {      ETLog.d(TAG, "Device not compatible of camera2 api" + e);     }     return false;  } 

文章来源: Camera2 API AutoFocus with Samsung S5