媒体播放器

使用 Qt Quick 播放音频和视频。

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

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工程结构

This applications architecture is comprised of three custom QML modules:

MediaControl
MediaPlayer
Config

This is also reflected in the top-level CMakeLists.txt 文件：

add_subdirectory(MediaPlayer)
add_subdirectory(MediaControls)
add_subdirectory(Config)
target_link_libraries(MediaPlayerApp PRIVATE
    Qt6::Core
    Qt6::Svg
    Qt6::Quick
    Qt6::Multimedia
    MediaControlsplugin
    MediaPlayerplugin
    Configplugin

Each QML module is created using the qt_add_qml_module macro, for example see how the Config module is created.

qt_add_library(Config STATIC)
set_source_files_properties(Config.qml
    PROPERTIES
        QT_QML_SINGLETON_TYPE true
)
qt_add_qml_module(Config
    URI "Config"
    OUTPUT_DIRECTORY Config
    QML_FILES
        "Config.qml"
)

Qt Quick application

At its core this is a QML application, see 采用 Qt Quick 快速入门编程 for information specific to that. This documentation is focused on how this example utilizes the Qt Multimedia QML 类型 .

The custom Config QML module

This type controls themes and layouts for an application, depending on the target operating system.

First we declare it a singleton, as we only need it to be instantiated once and creating copies would be a waste of resources.

To do that we add the following at the top of Config.qml

pragma Singleton

We then create a qmldir file in the Config directory named qmldir that contains the following:

module Config
singleton Config 1.0 Config.qml

Now to use it in our application, see how it is referenced in MediaPlayer 's Main.qml file:

    color: Config.mainColor

The custom MediaControls QML module

This module holds all the types used to define the application's controls including:

AudioControl.qml
ControlImages.qml
CustomButton.qml
CustomRadioButton.qml
CustomSlider.qml
PlaybackControl.qml
PlaybackRateControl.qml
PlaybackSeekControl.qml

See each specific type's definition file for detail on how these controls are implemented. They are an evolution of the controls in the QML 媒体播放器范例 .

The custom `MediaPlayer` QML 模块

This module has the Main.qml file which declares where most of the top level types for the application are used, and crucially where the Qt Multimedia MediaPlayer and VideoOutput QML types are declared.

    MediaPlayer {
        id: mediaPlayer
        playbackRate: playbackControl.playbackRate
        videoOutput: videoOutput
        audioOutput: AudioOutput {
            id: audio
            volume: playbackControl.volume
        }
        source: new URL("https://download.qt.io/learning/videos/media-player-example/Qt_LogoMergeEffect.mp4")
        function updateMetadata() {
            root.metadataInfo.clear()
            root.metadataInfo.read(mediaPlayer.metaData)
        }
        onMetaDataChanged: updateMetadata()
        onActiveTracksChanged: updateMetadata()
        onErrorOccurred: {
            errorPopup.errorMsg = mediaPlayer.errorString
            errorPopup.open()
        }
        onTracksChanged: {
            settingsInfo.tracksInfo.selectedAudioTrack = mediaPlayer.activeAudioTrack
            settingsInfo.tracksInfo.selectedVideoTrack = mediaPlayer.activeVideoTrack
            settingsInfo.tracksInfo.selectedSubtitleTrack = mediaPlayer.activeSubtitleTrack
            updateMetadata()
        }
        onMediaStatusChanged: {
            if ((MediaPlayer.EndOfMedia === mediaStatus && mediaPlayer.loops !== MediaPlayer.Infinite) &&
                    ((root.currentFile < playlistInfo.mediaCount - 1) || playlistInfo.isShuffled)) {
                if (!playlistInfo.isShuffled) {
                    ++root.currentFile
                }
                root.playMedia()
            } else if (MediaPlayer.EndOfMedia === mediaStatus && root.playlistLooped && playlistInfo.mediaCount) {
                root.currentFile = 0
                root.playMedia()
            }
        }
    }
    VideoOutput {
        id: videoOutput
        anchors.top: fullScreen || Config.isMobileTarget ? parent.top : menuBar.bottom
        anchors.bottom: fullScreen ? parent.bottom : playbackControl.top
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.leftMargin: fullScreen ? 0 : 20
        anchors.rightMargin: fullScreen ? 0 : 20
        visible: mediaPlayer.hasVideo
        property bool fullScreen: false
        TapHandler {
            onDoubleTapped: {
                if (parent.fullScreen) {
                    root.showNormal()
                } else {
                    root.showFullScreen()
                }
                parent.fullScreen = !parent.fullScreen
            }
            onTapped: {
                root.closeOverlays()
            }
        }
    }

The module contains the other customs types used for retrieving and displaying file information, as well as calling the file picker.

ErrorPopup.qml
Images.qml
MetadataInfo.qml
PlayerMenuBar.qml
PlaylistInfo.qml
SettingsInfo.qml
ThemeInfo.qml
TouchMenu.qml
TracksInfo.qml
TracksOptions.qml
UrlPopup.qml

See each specific type's definition file for detail on how types are implemented. Some are an evolution of those found in QML 媒体播放器范例 .

New functionality

This example application has some new functionality implemented by types, such as PlaylistInfo and ThemeInfo . See the respective .qml files for detail on how these are implemented.

范例工程 @ code.qt.io