Introduce MediaPlayer::videoOutput property

This property holds the target video output,
and allows to render video to multiple items.

    MediaPlayer {
        videoOutput: [videoOutput1, 1, "ignored", videoOutput2.videoSurface]
    }

Incorrect inputs are ignored.

The property also accepts single either QAbstractVideoSurface or QDeclarativeVideoOutput objects.

Task-number: QTBUG-32939
Change-Id: I41fc557dcac60be6d70b3889036ff4ae75734cc0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

3 files changed, 70 insertions, 2 deletions

diff --git a/src/multimedia/doc/snippets/multimedia-snippets/multimedia-snippets.pro b/src/multimedia/doc/snippets/multimedia-snippets/multimedia-snippets.pro
index c13090a79..a46b20bd0 100644
--- a/src/multimedia/doc/snippets/multimedia-snippets/multimedia-snippets.pro
+++ b/src/multimedia/doc/snippets/multimedia-snippets/multimedia-snippets.pro
@@ -22,4 +22,5 @@ SOURCES += \
 
 OTHER_FILES += \
     soundeffect.qml \
-    qtvideosink.qml
+    qtvideosink.qml \
+    multiple-videooutputs.qml
diff --git a/src/multimedia/doc/snippets/multimedia-snippets/multiple-videooutputs.qml b/src/multimedia/doc/snippets/multimedia-snippets/multiple-videooutputs.qml
new file mode 100644
index 000000000..e3c1587f6
--- /dev/null
+++ b/src/multimedia/doc/snippets/multimedia-snippets/multiple-videooutputs.qml
@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Window 2.2
+import QtMultimedia 5.15
+
+//! [complete]
+Item {
+    MediaPlayer {
+        id: mediaplayer
+        autoPlay: true
+        source: "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"
+        videoOutput: [v1, v2]
+    }
+
+    VideoOutput {
+        id: v1
+        anchors.fill: parent
+    }
+
+    Window {
+        visible: true
+        width: 480; height: 320
+        VideoOutput {
+            id: v2
+            anchors.fill: parent
+        }
+    }
+}
+//! [complete]
diff --git a/src/multimedia/playback/qmediaplayer.cpp b/src/multimedia/playback/qmediaplayer.cpp
index 9b51bcddf..d96cb3a95 100644
--- a/src/multimedia/playback/qmediaplayer.cpp
+++ b/src/multimedia/playback/qmediaplayer.cpp
@@ -1184,7 +1184,7 @@ void QMediaPlayer::setVideoOutput(QAbstractVideoSurface *surface)
 
 void QMediaPlayer::setVideoOutput(const QVector<QAbstractVideoSurface *> &surfaces)
 {
-    setVideoOutput(new QVideoSurfaces(surfaces, this));
+    setVideoOutput(!surfaces.empty() ? new QVideoSurfaces(surfaces, this) : nullptr);
 }
 
 /*! \reimp */