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Subtitles in Windows Store Apps

Posted by Deepak Arora Articles | Windows Store Apps November 28, 2012
In this article I described how to create a Windows Store App to provide subtitles during Playback using JavaScript.
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Introduction

Today we are going to learn how to create Windows Store Apps for zooming the picture size using JavaScript. The Windows Store app platform allows apps to provide subtitles during video playback using the "track" element and "text track model". This app code shows how to use a WebVTT file, which is natively supported by Windows Store apps. You can playback a video file in the following video tag, and then turn On or Off the subtitles during playback.

To start the creation of the apps, add two JavaScript pages by right-clicking on the js folder in the Solution Explorer and select Add > new item > JavaScript Page and then provide an appropriate name. In the same way, add one HTML page to your project.

subtitles-in-windows-store-app.jpg

Write the following code in default.html:

<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8" />

    <title>app</title>

    <link rel="stylesheet" href="//Microsoft.WinJS.1.0/css/ui-light.css" />

    <script src="//Microsoft.WinJS.1.0/js/base.js"></script>

    <script src="//Microsoft.WinJS.1.0/js/ui.js"></script> 

    <link rel="stylesheet" href="/css/default.css" />

    <script src="/js/script1.js"></script>

    <script src="/js/default.js"></script>

</head>

<body role="application" style="background-color:lightsalmon">

    <center><div id="rootGrid">

         <div id="content">

            <h1 id="featureLabel"></h1>

            <div id="contentHost"></div>

        </div>

         </div></center>

</body>

</html>

Write the following code in default.js:
 

(function () {

    "use strict";

    var appTitle = "";

    var pages = [      

        { url: "page.html"}

    ];

 

    function activated(eventObject) {

        if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) {         

            eventObject.setPromise(WinJS.UI.processAll().then(function () {               

                var url = WinJS.Application.sessionState.lastUrl || pages[0].url;

                return WinJS.Navigation.navigate(url);

            }));

        }

    }

    WinJS.Navigation.addEventListener("navigated", function (eventObject) {

        var url = eventObject.detail.location;

        var host = document.getElementById("contentHost");       

        host.winControl && host.winControl.unload && host.winControl.unload();

        WinJS.Utilities.empty(host);

        eventObject.detail.setPromise(WinJS.UI.Pages.render(url, host, eventObject.detail.state).then(function () {

            WinJS.Application.sessionState.lastUrl = url;

        }));

    });

    WinJS.Namespace.define("App", {

        appTitle: appTitle,

pages: pages,

        videoOnError: function (error) {

            switch (error.target.error.code) {

                case error.target.error.MEDIA_ERR_ABORTED:

                    App.displayError("You aborted the video playback.");

                    break;

                case error.target.error.MEDIA_ERR_NETWORK:

                    App.displayError("A network error caused the video download to fail part-way.");

                    break;

                case error.target.error.MEDIA_ERR_DECODE:

                    App.displayError("The video playback was aborted due to a corruption problem or because the video used features your browser did not support.");

                    break;

                case error.target.error.MEDIA_ERR_SRC_NOT_SUPPORTED:

                    App.displayError("The video could not be loaded, either because the server or network failed or because the format is not supported.");

                    break;

                default:

                    App.displayError("An unknown error occurred.");

                    break;

            }

        },

        displayStatus: function (msg) {

            WinJS.log && WinJS.log(msg, null, "status");

        },

 

        displayError: function (msg) {

            WinJS.log && WinJS.log(msg, null, "error");

        }

    });

    WinJS.Application.addEventListener("activated", activated, false);

    WinJS.Application.start();

})();


Write the following code in page.html:
 

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

    <title></title>

    <script src="/js/Subtitles.js"></script>

</head>

<body>

    <div data-win-control="App.pageInput">       

        <p></p>

        <button class="action" id="play">Play</button>

        <button class="action" id="stop">Stop Video</button>

        <button class="action" id="subtitleOn">Turn On Subtitle Rendering</button>

        <button class="action" id="subtitleOff">Turn Off Subtitle Rendering</button>

        <br />

        <br />

    </div>

    <div data-win-control="App.pageOutput">

        <video id="subtitleVideo" style="position: relative; z-index: auto; width: 50%;"

            src="http://ie.microsoft.com/testdrive/Videos/BehindIE9AllAroundFast/Video.mp4"

            poster="images/Win8MediaLogo.png" loop controls>

            <track id="page3entrack" src="media/sample-subtitle-en.vtt" kind="subtitles"

                srclang="en" default>

        </video>

    </div>

</body>

</html> 


Write the following code in script.js:

 

(function () {

    "use strict";

    var page = WinJS.UI.Pages.define("page.html", {

        ready: function (element, options) {

            WinJS.Utilities.query("#play").listen("click", play);

            WinJS.Utilities.query("#stop").listen("click", stopPlayback);

            WinJS.Utilities.query("#subtitleOn").listen("click", subtitleOn);

            WinJS.Utilities.query("#subtitleOff").listen("click", subtitleOff);

            WinJS.Utilities.query("#subtitleVideo").listen("error", App.videoOnError);

        },

        unload: function () {

            stopPlayback();

        }

    });

    function play() {

        WinJS.Utilities.query("#subtitleVideo")[0].play();

    }

    function stopPlayback() {

        var video = WinJS.Utilities.query("#subtitleVideo")[0];

 

        if (!video.paused) {

            video.pause();

        }

    }

    function subtitleOn() {

        var video = WinJS.Utilities.query("#subtitleVideo")[0];

 

        video.textTracks[0].mode = TextTrack.SHOWING;

    }

    function subtitleOff() {

        var video = WinJS.Utilities.query("#subtitleVideo")[0];

        video.textTracks[0].mode = TextTrack.OFF;

    }

})();

  
Write the following code in script1.js:

(function () {

    var pageOutput = WinJS.Class.define(

        function (element, options) {

            element.winControl = this;

            this.element = element;

            new WinJS.Utilities.QueryCollection(element)

                        .setAttribute("role", "region")

                        .setAttribute("aria-labelledby", "outputLabel")

                        .setAttribute("aria-live", "assertive");

            element.id = "output";

 

            this._addOutputLabel(element);

            this._addStatusOutput(element);

        }, {

            _addOutputLabel: function (element) {

                var label = document.createElement("h2");

                label.id = "outputLabel";

                label.textContent = "Output";

                element.parentNode.insertBefore(label, element);

            },

            _addStatusOutput: function (element) {

                var statusDiv = document.createElement("div");

                statusDiv.id = "statusMessage";

                element.insertBefore(statusDiv, element.childNodes[0]);

            }

        }

    );

    var currentpageUrl = null;

    WinJS.Navigation.addEventListener("navigating", function (evt) {

        currentpageUrl = evt.detail.location;

    });

    WinJS.log = function (message, tag, type) {       

            var statusDiv = document.getElementById("statusMessage");           

    };   

    function activated(e) {

        WinJS.Utilities.query("#featureLabel")[0].textContent = App.appTitle;

    }

    WinJS.Application.addEventListener("activated", activated, false);

    WinJS.Namespace.define("App", {      

        pageOutput: pageOutput

    });   

})();


Output:

subtitles-in-windows-store-apps.jpg

Summary


In this article I described how to create a Windows Store App to provide subtitles during Playback using JavaScript. I hope this article has helped you in understanding this topic. Please share it. If you know more about this, your feedback and constructive contributions are welcome.

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