Android Camera Preview Check getPhotoPreviewFpsRange(Parameters params)

Description

For still image capture, we need to get the right fps range such that the camera can slow down the framerate to allow for less-noisy/dark viewfinder output in dark conditions.

License

Apache License

Parameter

Parameter	Description
params	Camera's parameters.

Return

null if no appropiate fps range can't be found. Otherwise, return the right range.

Declaration

public static int[] getPhotoPreviewFpsRange(Parameters params)

Method Source Code

/*//from w w  w  . j  a v  a 2  s  .  c om
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.app.Activity;
import android.app.AlertDialog;
import android.app.admin.DevicePolicyManager;
import android.content.ActivityNotFoundException;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.RectF;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.Size;
import android.location.Location;
import android.net.Uri;
import android.os.Handler;
import android.os.ParcelFileDescriptor;
import android.telephony.TelephonyManager;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.Display;
import android.view.OrientationEventListener;
import android.view.Surface;
import android.view.View;
import android.view.WindowManager;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.Toast;
import com.android.camera.CameraActivity;
import com.android.camera.CameraDisabledException;
import com.android.camera.CameraHolder;
import com.android.camera.CameraManager;
import com.android.camera.util.IntentHelper;
import com.android.camera2.R;
import java.io.Closeable;
import java.io.IOException;
import java.lang.reflect.Method;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.StringTokenizer;

public class Main{
    private static final String TAG = "Util";
    private final static int MAX_PREVIEW_FPS_TIMES_1000 = 400000;
    private final static int PREFERRED_PREVIEW_FPS_TIMES_1000 = 30000;
    /**
     * For still image capture, we need to get the right fps range such that the
     * camera can slow down the framerate to allow for less-noisy/dark
     * viewfinder output in dark conditions.
     *
     * @param params Camera's parameters.
     * @return null if no appropiate fps range can't be found. Otherwise, return
     *         the right range.
     */
    public static int[] getPhotoPreviewFpsRange(Parameters params) {
        return getPhotoPreviewFpsRange(params.getSupportedPreviewFpsRange());
    }
    public static int[] getPhotoPreviewFpsRange(List<int[]> frameRates) {
        if (frameRates.size() == 0) {
            Log.e(TAG, "No suppoted frame rates returned!");
            return null;
        }

        // Find the lowest min rate in supported ranges who can cover 30fps.
        int lowestMinRate = MAX_PREVIEW_FPS_TIMES_1000;
        for (int[] rate : frameRates) {
            int minFps = rate[Parameters.PREVIEW_FPS_MIN_INDEX];
            int maxFps = rate[Parameters.PREVIEW_FPS_MAX_INDEX];
            if (maxFps >= PREFERRED_PREVIEW_FPS_TIMES_1000
                    && minFps <= PREFERRED_PREVIEW_FPS_TIMES_1000
                    && minFps < lowestMinRate) {
                lowestMinRate = minFps;
            }
        }

        // Find all the modes with the lowest min rate found above, the pick the
        // one with highest max rate.
        int resultIndex = -1;
        int highestMaxRate = 0;
        for (int i = 0; i < frameRates.size(); i++) {
            int[] rate = frameRates.get(i);
            int minFps = rate[Parameters.PREVIEW_FPS_MIN_INDEX];
            int maxFps = rate[Parameters.PREVIEW_FPS_MAX_INDEX];
            if (minFps == lowestMinRate && highestMaxRate < maxFps) {
                highestMaxRate = maxFps;
                resultIndex = i;
            }
        }

        if (resultIndex >= 0) {
            return frameRates.get(resultIndex);
        }
        Log.e(TAG, "Can't find an appropiate frame rate range!");
        return null;
    }
}