JavaScript configuration variables that are added via ResourceLoaderGetConfigVars are inserted into the start-up module, which is on the critical path to loading page content. MwEmbedSupport uses this interface to inject the contents of two configuration files, MediaWikiSupport.config.php & MwEmbedSupport.config.php, which contain largely static configuration data that is MwEmbedSupport-specific, the loading of which could be limited to pages containing timed media, and deferred until DOMContentLoaded or later.
If the configuration variables truly are static, they can be hard-coded in a JavaScript file and included in the scripts array of the the MwEmbedSupport ResourceLoader module. If it is important for these values to be configurable via PHP, a custom ResourceLoader module class should be written. For an example of this technique, refer to includes/ResourceLoaderULSJsonMessageModule.php in the UniversalLanguageSelector extension.
List and values in Wikimedia production as of 2018-08-17:
AjaxRequestTimeout: 30
EmbedPLayer.IFramePlayer.DomainWhiteList: "*"
EmbedPlayer.AttributionButton: {title: "Kaltura html5 video library", href: "http://www.kaltura.com", class: "kaltura-icon", style: {…}, iconurl: false}
EmbedPlayer.BlackPixel: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkqAcAAIUAgUW0RjgAAAAASUVORK5CYII="
EmbedPlayer.CodecPreference: ["vp9", "webm", "h264", "ogg", "mp3", "ogvjs"]
EmbedPlayer.ControlsHeight: 31
EmbedPlayer.DefaultSize: "400x300"
EmbedPlayer.DefaultSkin: "mvpcf"
EmbedPlayer.DisableVideoTagSupport: false
EmbedPlayer.EnableFlavorSelector: false
EmbedPlayer.EnableFullscreen: true
EmbedPlayer.EnableIframeApi: true
EmbedPlayer.EnableIpadHTMLControls: true
EmbedPlayer.EnableIpadNativeFullscreen: false
EmbedPlayer.EnableRightClick: true
EmbedPlayer.EnableTimeDisplay: true
EmbedPlayer.EnableURLTimeEncoding: "flash"
EmbedPlayer.EnableVolumeControl: true
EmbedPlayer.EnabledOptionsMenuItems: ["playerSelect", "download", "share", "aboutPlayerLibrary"]
EmbedPlayer.FirefoxLink: "http://www.mozilla.com/en-US/firefox/upgrade.html?from=mwEmbed"
EmbedPlayer.ForceLargeReplayButton: false
EmbedPlayer.FullScreenZIndex: 999998
EmbedPlayer.FullscreenTip: true
EmbedPlayer.KalturaAttribution: true
EmbedPlayer.LibraryPage: "http://www.kaltura.org/project/HTML5_Video_Media_JavaScript_Library"
EmbedPlayer.MonitorRate: 250
EmbedPlayer.NativeControls: false
EmbedPlayer.NativeControlsMobileSafari: true
EmbedPlayer.NewWindowFullscreen: false
EmbedPlayer.NotPlayableDownloadLink: true
EmbedPlayer.OverlayControls: true
EmbedPlayer.PageDomainIframe: true
EmbedPlayer.ReplaceSources: null
EmbedPlayer.RewriteSelector: "video,audio,playlist"
EmbedPlayer.ShareEmbedMode: "iframe"
EmbedPlayer.ShowNativeWarning: true
EmbedPlayer.ShowPlayerAlerts: true
EmbedPlayer.SkinList: ["mvpcf", "kskin"]
EmbedPlayer.TimeDisplayWidth: 85
EmbedPlayer.UseFlashOnAndroid: false
EmbedPlayer.WaitForMeta: true
EmbedPlayer.WebKitPlaysInline: false
EmbedPlayer.iPhoneShowHTMLPlayScreen: true
MediaWiki.DefaultProvider: "local"
MediaWiki.ApiProviders: { commons: { url: "//commons.wikimedia.beta.wmflabs.org/w/api.php" } }
MediaWiki.ApiPostActions: [ "login", "purge", "rollback", "delete", "undelete", "protect", "block", "unblock", "move", "edit", "upload", "emailuser", "import", "userrights" ]
TimedText.BelowVideoBlackBoxHeight: 40
TimedText.BottomPadding: 10
TimedText.NeedsTranscriptCategory: "Videos needing subtitles"
TimedText.ShowRequestTranscript: false