Qt Multimedia 的變化

Qt 5 的 Qt Multimedia 模塊組閤 (並替換) 2 個較舊模塊，也就是來自 Qt 4 的 Qt Multimedia 模塊，和來自 Qt Mobility 的 Qt Multimedia Kit 模塊。移植使用來自 Qt 4 的 Qt Multimedia 現有代碼可以付齣最少努力，但移植使用 Qt Multimedia Kit 代碼的過程可能更復雜。變化特徵章節突顯移植相關變化。

另請注意：基於 Widget 的類，譬如 QVideoWidget ，現在在稱為 Qt Multimedia 小部件的單獨模塊中。

Qt 5.0 的新特徵

Qt Multimedia 有許多新特徵：

擴展 QML API
除瞭 Video QML 類型，現在可選使用 MediaPlayer and VideoOutput together
QML Torch class
New QAudioRecorder class
音量支持 QAudioOutput and QAudioInput
更多範例和文檔編製
QSound 從 Qt GUI 移至 Qt Multimedia
QSoundEffect 現可用於 C++ 及 QML
FM 無綫電數據係統類和類型現在可用 ( QRadioData , RadioData )
各種其它 API 改進和 Bug 修正

移除特徵

已移除先前由 Qt Multimedia 或 Qt Multimedia Kit 提供的許多類或函數。

移除特徵	注意事項
QMediaImageViewer	移除此類 (及相關控件和服務)，由於它們的功能不適於很多應用程序

變化特徵

先前由 Qt Multimedia 或 Qt Multimedia Kit 提供的許多類已以可能影響先前編寫代碼的方式被改變。該錶突顯這種改變。

變化特徵	注意事項
`qmake` 工程文件變化	先前，要使用 Qt Multimedia Kit， `qmake` 工程文件必須包含 CONFIG += mobility MOBILITY + = multimedia 現在，隻需編寫 QT += multimedia 或者，若想要使用 Widget 類， QT += multimedia multimediawidgets
名稱空間	The `QtMultimediaKit` namespace has been renamed to QMultimedia . This affects a few enumerations, namely `SupportEstimate` , `EncodingQuality` , `EncodingMode` and `AvailabilityStatus` . Searching and replacing `QtMultimediaKit` with `QMultimedia` will greatly aid porting efforts. Metadata have been split off into their own namespace, QMediaMetaData .
元數據類型	In Qt Multimedia Kit, pre-defined metadata keys were enumerations in the `QtMultimediaKit` namespace. These pre-defined keys have been changed to string literals in the `QMediaMetaData` namespace, for consistency with extended keys.
元數據訪問器方法	In Qt Multimedia Kit, there were two different families of methods to access metadata. Functions such as `QMediaObject::metaData()` operated on pre-defined metadata using enumerated keys, while functions such as `QMediaObject::extendedMetaData()` operated on extended metadata using string keys. Qt 5 combines both families into one (e.g. QMediaObject::metaData ()), which can operate on both pre-defined and extended metadata, using string keys.
Qt Metatype 配準	Qt 5 registers many more classes and types with the meta-object system than before. If you have previously applied Q_DECLARE_METATYPE macros to any Qt Multimedia class, you will probably need to remove them.
QSoundEffect availability	The SoundEffect QML type was publicly accessible in Qt Multimeda Kit, and now the C++ version is officially public too. If your code contains the previously undocumented QSoundEffect , you may need to update it.
攝像頭控件	A large number of the camera controls ( QCameraImageProcessingControl , QCameraFocusControl , etc.) have been updated to address a number of design flaws. In particular, a number of discrete accessor methods have been collapsed into parametrized methods, and the ranges or data types of some parameters have been adjusted.