Camera2 API 自动对焦与三星 S5

我正在 Samsung S5 上使用新的 Camera2 API。该设备报告的支持的硬件级别是LEGACY，这很好。

但是，我似乎无法自动对焦该设备。触发自动对焦的请求如下所示：

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();
}

请求发送后，请求的结果总是CONTROL_AF_STATE_ACTIVE_SCAN偶尔CONTROL_AF_STATE_NOT_FOCUSED_LOCKED.

奇怪的是，当状态CONTROL_AF_STATE_NOT_FOCUSED_LOCKED，自动对焦返回到CONTROL_AF_STATE_ACTIVE_SCAN状态一段时间然后回到CONTROL_AF_STATE_NOT_FOCUSED_LOCKED，导致无限聚焦循环。根据文档，当状态为CONTROL_AF_STATE_NOT_FOCUSED_LOCKED...

镜头将保持静止，直到 AF 模式 (android.control.afMode) 更改或新的 AF 触发器发送到相机设备 (android.control.afTrigger)。

我想知道这种差异是否是因为硬件水平LEGACY我应该重新使用已弃用的 Camera API，但这对于自动对焦等如此流行的功能来说似乎很疯狂。

是否有任何建议如何处理正在报告的设备LEGACY?

我分枝形式谷歌的 Camera2Basic 示例并将其更改为使用CaptureRequest.CONTROL_AF_MODE_AUTO代替CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE

您可以从 git 获取该项目并测试它 -https://github.com/pinhassi/android-Camera2Basic

或者只是将其添加到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;
}

然后，添加到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;
        }

并替换所有出现的：

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);