方法
getPlaybackPositionInMs()
getPlaybackPositionInMs():number | null
返回值
number | null
getTextTrackPreference()
getTextTrackPreference(): ITrackPreference | null
返回值
ITrackPreference | null
getAudioTrackPreferences()
getAudioTrackPreferences(): ITrackPreference[]
返回值
ITrackPreference[]
