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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms
** and conditions contained in a signed written agreement between you
** and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\group qml-multimedia
\title QML Multimedia Plugin
QML Support for the Qt Multimedia API.
*/
/*!
\page qml-multimedia.html
\title Qt Multimedia QML API
\brief A QML API for the Qt Multimedia module.
\section1 Overview
The Qt Multimedia module gives developers a simplified way to use audio and video playback, and access camera functionality. The Multimedia QML API provides a QML friendly interface to these features.
\section1 Types
\section2 Audio
\l Audio is an easy way to add audio playback to a Qt Quick
scene. QtMultimedia provides properties for control, methods (functions) and signals.
The code extract below shows the creation and use of an Audio instance.
\qml
import QtQuick 2.0
import QtMultimedia 5.0
// ...
Item {
width: 640
height: 360
Audio {
id: playMusic
source: "music.wav"
}
MouseArea {
id: playArea
anchors.fill: parent
onPressed: { playMusic.play() }
}
}
\endqml
The snippet above shows how the inclusion of \e playMusic enables audio features on the type that contains it. So that when the parent's MouseArea is clicked the \l {Audio::play()}{play()} method of Audio is run. Other typical audio control methods are available such as \l {Audio::pause}{pause()} and \l {Audio::stop()}{stop()}.
Much of the getting / setting of \l Audio parameters is done through properties. These include
\table 70%
\header
\li Property
\li Description
\row
\li \l {Audio::source}{source}
\li The source URL of the media.
\row
\li \l {Audio::autoLoad}{autoLoad}
\li Indicates if loading of media should begin immediately.
\row
\li \l{Audio::playing}{playing}
\li Indicates that the media is playing.
\row
\li \l {Audio::paused}{paused}
\li The media is paused.
\row
\li \l{Audio::status}{status}
\li The status of media loading.
\row
\li \l{Audio::duration}{duration}
\li Amount of time in milliseconds the media will play.
\row
\li \l{Audio::position}{position}
\li Current position in the media in milliseconds of play.
\row
\li \l{Audio::volume}{volume}
\li Audio output volume: from 0.0 (silent) to 1.0 (maximum)
\row
\li \l{Audio::muted}{muted}
\li Indicates audio is muted.
\row
\li \l{Audio::bufferProgress}{bufferProgress}
\li Indicates how full the data buffer is: 0.0 (empty) to 1.0 (full).
\row
\li \l{Audio::seekable}{seekable}
\li Indicates whether the audio position can be changed.
\row
\li \l{Audio::playbackRate}{playbackRate}
\li The rate at which audio is played at as a multiple of the normal rate.
\row
\li \l{Audio::error}{error}
\li An error code for the error state including NoError
\row
\li \l{Audio::errorString}{errorString}
\li A description of the current error condition.
\endtable
The set of signals available allow the developer to create custom behavior when the following events occur,
\table 70%
\header
\li Signal
\li Description
\row
\li \l{Audio::playing}{playing}
\li Called when playback is started, or when resumed from paused state.
\row
\li \l{Audio::paused}{paused}
\li Called when playback is paused.
\row
\li \l{Audio::stopped}{stopped}
\li Called when playback is stopped.
\row
\li \l{Audio::error}{error}
\li Called when the specified error occurs.
\endtable
\section2 Camera
\l Camera enables still image and video capture using
QML. It has a number of properties that help setting it up.
The details of using a \l Camera are described in further depth
in the \l {Camera Overview} and in the corresponding reference documentation.
\section2 Video
Adding video playback, with sound, to a Qt Quick scene is also easy. The process is very similar to that of Audio above, in fact \l {Video} shares many of the property names, methods and signals. Here is the equivalent sample code to implement video playback in a scene
\qml
Video {
id: video
width : 800
height : 600
source: "video.avi"
MouseArea {
anchors.fill: parent
onClicked: {
video.play()
}
}
focus: true
Keys.onSpacePressed: video.paused = !video.paused
Keys.onLeftPressed: video.position -= 5000
Keys.onRightPressed: video.position += 5000
}
\endqml
There are similar features like \l {Video::play()}{play()} with new
features specific to video.
In the above sample when the parent of MouseArea is clicked, an area of 800x600 pixels with an id of 'video', the source "video.avi" will play in that area. Notice also that signals for the \l Keys have been defined so that a spacebar will toggle the pause button; the left arrow will move the current position in the video to 5 seconds previously; and the right arrow will advance the current position in the video by 5 seconds.
Most of the differences will obviously be about video control and information. There are many properties associated with \l {Video}, most of them deal with meta-data, control of the video media and aspects of presentation.
\section2 SoundEffect
\l SoundEffect provides a way to play short sound effects, like in video games. Multiple sound effect instances can be played simultaneously.
You should use \l Audio for music playback.
\qml
import QtQuick 2.0
import QtMultimedia 5.0
Item {
width: 640
height: 360
SoundEffect {
id: effect
source: "test.wav"
}
MouseArea {
id: playArea
anchors.fill: parent
onPressed: { effect.play() }
}
}
\endqml
In the above sample the sound effect will be played when the MouseArea is clicked.
For a complete description of this type, see \l SoundEffect
\section1 Multimedia QML Types
\annotatedlist multimedia_qml
*/
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