// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \example video/mediaplayer
    \title QML Media Player Example
    \ingroup multimedia_examples
    \ingroup video_examples_qml
    \brief Playing audio and video using Qt Quick.
    \meta {tag} {quick}
    \meta {tag} {player}
    \image qmlmediaplayer.jpg

    This example demonstrates a simple multimedia player that can play
    audio and video files using various codecs.

    \include examples-run.qdocinc

    \section1 Overview
    At its core this is a QML application, see
    \l{Getting Started Programming with Qt Quick} for information specific to
    that. This documentation is focused on how this example utilizes the
    \l{Qt Multimedia QML types}.

    \image architecture-overview.gif

    \section1 Using MediaPlayer and VideoOutput
    In \c main.qml a MediaPlayer instance is connected to a VideoOutput to
    play back the video:

    \quotefromfile video/mediaplayer/main.qml
    \skipto MediaPlayer
    \printuntil videoOutput: videoOutput

    \c videoOutput is declared like so:

    \skipto VideoOutput {
    \printto MetadataInfo {

    \section1 PlayerMenuBar
    \image PlayerMenuBar.gif
    This QML type handles media selection from a url or local file, exiting the
    application, viewing meta data, and the selection of available video, audio
    or subtitle tracks.

    \quotefromfile video/mediaplayer/PlayerMenuBar.qml
    Accessing the mediaPlayer object is done through properties:
    \skipto required property
    \printuntil TracksInfo subtitleTracksInfo

    \section2 fileDialog
    A FileDialog, \c fileDialog, is created with an \c onAccepted function that
    will stop \c mediaPlayer, load the source by setting the
    \l{MediaPlayer::source}{source} property and then play it automatically:
    \skipto FileDialog
    \printto MenuBar

    This is triggered in the Menu \c File, which is a child of the MenuBar:
    \skipto MenuBar
    \printto }

    \section2 loadUrl
    \image url.png
    While \c urlPopup handles prompting and capturing a url, it is the \c loadUrl
    function that interacts with \c mediaPlayer like so:
    \quotefromfile video/mediaplayer/PlayerMenuBar.qml
    \skipto function loadUrl
    \printto function closeOverlays(){

    \section2 Getting meta data
    \image meta-data.png

    In the declaration of \c mediaPlayer, in \c main.qml, there is the function
    \c updateMetadata():

    \quotefromfile video/mediaplayer/main.qml
    \skipto function updateMetadata(
    \printto }

    It is called in the following places:
    \skipto onMetaDataChanged:
    \printto onActiveTracksChanged: { updateMetadata() }

    Reading MetaData is done by the \c MetadataInfo type's \c read() function
    \quotefromfile video/mediaplayer/MetadataInfo.qml
    \skipto function read(metadata) {
    \printto ListModel

    The information is displayed via an \l[QML]{Overlay} item.

    \section2 Tracks information and control
    \youtube OqosZsDqvzQ
    This is defined in \c TracksInfo.qml and reading available tracks is done in
    a similar way to \c MetadataInfo:
    \quotefromfile video/mediaplayer/TracksInfo.qml
    \skipto function read(metadata
    \printto ListModel

    To set a track, the property \c selectedTrack is set like so:
    \skipto ListView
    \printto Text

    The \c onSelectectedTrackChanged signal, in each relevant \c TracksInfo
    instance in \c main.qml, is what makes changes to \c mediaPlayer like so:
    \quotefromfile video/mediaplayer/main.qml
    \skipto id: audioTracksInfo
    \printuntil audioTracksInfo.selectedTrack

    \section1 playbackControlPanel
    \image playbackControlPanel.gif

    This item has controls for \l{Playback control}, \l{Play Pause Stop},
    \l{Playback rate control} and \l{Playback seek control}.

    \section2 Playback control
    This qml type handles media playback and interacts with the MediaPlayer in
    \c main.qml.

    Here are the property definitions.
    \quotefromfile video/mediaplayer/PlaybackControl.qml
    \skipto required property
    \printto property alias

    Connections:
    \skipuntil Connections
    \printto HoverHandler

    \section2 Play Pause Stop
    \image play-pause-stop.gif
    \l{MediaPlayer::play()}{Play}, \l{MediaPlayer::stop()}{stop} and
    \l{MediaPlayer::pause()}{pause} interactions with the MediaPlayer object
    are done like so:
    \skipto RoundButton
    \printto Item {

    Playback states done using \l{MediaPlayer::playbackState}{playbackstate}
    like so:
    \skipuntil states:
    \printuntil ]


    \section2 Playback seek control

    \youtube sf_yv01UtIw

    Defined in \c PlaybackSeekControl.qml, this component comprises of an item
    with a Text, \c mediaTime, and \l[QML]{Slider}, \c mediaSlider, in a RowLayout.

    \c mediaTime uses MediaPlayer's \l{MediaPlayer::position}{position} property
    like so:
    \quotefromfile video/mediaplayer/PlaybackSeekControl.qml
    \skipto Text {
    \printto Slider

    \c mediaSlider uses the MediaPlayer \l{MediaPlayer::seekable}{seekable},
    \l{MediaPlayer::duration}{duration}, and \l{MediaPlayer::position}{position}
    properties like so:
    \skipto Slider
    \printuntil }

    \section2 Playback rate control
    \youtube nHrBbW0H-pc

    This type is defined in \c PlaybackRateControl.qml like so:

    \quotefromfile video/mediaplayer/PlaybackRateControl.qml
    \skipto Slider
    \printuntil text:

    \section2 Audio control
    \image audio-control.gif
    This type is defined in \c AudioControl.qml, and utilizes the
    \l{AudioOutput::muted}{muted} and \l{AudioOutput::volume}{volume} properties
    of the AudioOutput instantiated within the MediaPlayer, which is
    instantiated in \c{main.qml}.

    \quotefromfile video/mediaplayer/AudioControl.qml
    \skipto required
    \printuntil value: 100.0
*/
