diff --git a/src/QrCodeScannerFilter.h b/src/QrCodeScannerFilter.h
index 3c07cbb..07a50f9 100644
--- a/src/QrCodeScannerFilter.h
+++ b/src/QrCodeScannerFilter.h
@@ -1,125 +1,125 @@
 /*
  *  Kaidan - A user-friendly XMPP client for every device!
  *
  *  Copyright (C) 2016-2019 Kaidan developers and contributors
  *  (see the LICENSE file for a full list of copyright authors)
  *
  *  Kaidan is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation, either version 3 of the License, or
  *  (at your option) any later version.
  *
  *  In addition, as a special exception, the author of Kaidan gives
  *  permission to link the code of its release with the OpenSSL
  *  project's "OpenSSL" library (or with modified versions of it that
  *  use the same license as the "OpenSSL" library), and distribute the
  *  linked executables. You must obey the GNU General Public License in
  *  all respects for all of the code used other than "OpenSSL". If you
  *  modify this file, you may extend this exception to your version of
  *  the file, but you are not obligated to do so.  If you do not wish to
  *  do so, delete this exception statement from your version.
  *
  *  Kaidan is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with Kaidan.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef QRCODESCANNERFILTER_H
 #define QRCODESCANNERFILTER_H
 
 #include <QObject>
 #include <QAbstractVideoFilter>
 #include <QFuture>
 
 #include <ZXing/DecodeHints.h>
 
 #include "QrCodeDecoder.h"
 #include "QrCodeVideoFrame.h"
 
 /**
  * video filter to be registered in C++, instantiated and attached in QML
  */
 class QrCodeScannerFilter : public QAbstractVideoFilter
 {
 	friend class QrCodeScannerFilterRunnable;
 
 	Q_OBJECT
 	Q_PROPERTY(QrCodeDecoder* decoder READ decoder)
 
 public:
 	/**
 	 * Instantiates a QR code scanner filter.
 	 *
 	 * @param parent parent object
 	 */
 	explicit QrCodeScannerFilter(QObject *parent = nullptr);
 	~QrCodeScannerFilter() override;
 
 	/**
 	 * @return decoder for decoding a video frame
 	 */
 	QrCodeDecoder *decoder();
-	QVideoFilterRunnable *createFilterRunnable();
+	QVideoFilterRunnable *createFilterRunnable() override;
 
 signals:
 	/**
 	 * Emitted when the scanning of an image did not succeed, i.e. no valid QR code was found.
 	 */
 	void scanningFailed();
 
 	/**
 	 * Emitted when the scanning of an image succeeded, i.e. a valid QR code was found and decoded.
 	 *
 	 * @param result decoded content of the QR code
 	 */
 	void scanningSucceeded(const QString& result);
 
 	/**
 	 * Emitted when a video frame with an unsupported format is received.
 	 *
 	 * @param format format of the video frame which is not supported
 	 */
 	void unsupportedFormatReceived(const QString& format);
 
 private:
 	QrCodeDecoder *m_decoder;
 
 	/**
 	 * frame of the video which may contain a QR code
 	 */
 	QrCodeVideoFrame m_frame;
 	QFuture<void> m_processThread;
 };
 
 /**
  * runnable which is created everytime the filter gets a new frame
  */
 class QrCodeScannerFilterRunnable : public QObject, public QVideoFilterRunnable
 {
 	Q_OBJECT
 
 public:
 	explicit QrCodeScannerFilterRunnable(QrCodeScannerFilter *m_filter);
 
 	/**
 	 * Runs the decoding in a new thread whenever a new frame is taken by the camera.
 	 */
-	QVideoFrame run(QVideoFrame *input, const QVideoSurfaceFormat &surfaceFormat, RunFlags flags);
+	QVideoFrame run(QVideoFrame *input, const QVideoSurfaceFormat &surfaceFormat, RunFlags flags) override;
 
 	/**
 	 * Converts a given frame, which may contain a QR code, to an image and then tries to decode it.
 	 *
 	 * @param videoFrame frame to be converted and which may contain a QR code to be decoded
 	 * @param filter filter of the current execution
 	 */
 	void processVideoFrameProbed(QrCodeVideoFrame videoFrame, QrCodeScannerFilter *filter);
 
 private:
 	QrCodeScannerFilter *m_filter;
 };
 
 #endif // QRCODESCANNERFILTER_H