javascript - 使用 JavaScript 更改 HTML 5.0 视频的视频分辨率

Question

更新:我使用的是 Fotorama 插件，似乎是底部菜单导致了问题。通过在视频标签周围放置 div 标签来禁用该菜单，使设置分辨率的功能起作用。谢谢帮助和鼓励。对于底部菜单，我创建了一个简单的菜单，使用链接按钮链接到与下一个视频相似的页面。

我编写了 JavaScript 代码，可以根据选项/选择元素的输入更改视频的分辨率。有用。问题是当我将完全相同的代码放入函数中时它停止工作(这样代码可以多次执行 - 每次更改选项/选择元素时。)

Here is an image of the videoplayer and the option/select-element I have added

这是选项/选择元素的代码:

<li class="porfolionav">
    <select id="selectQuality" onchange="changeVidQualityFunction()">
        <option value="1080" selected="selected" disabled="disabled">Videokvalitet</option>
        <option value="1080" id="1080">HD 1080</option>
        <option value="480" id="480">SD 480</option>
        <option value="320" id="320">SD 320</option>
    </select>
</li>

这是视频的代码:

<div class="fotorama" data-width="1209px" data-height="680px" data-allowfullscreen="false" data-arrows="true" data-click="true" data-swipe="true" data-autoplay="false" data-transition="slide" data-clicktransition="slide" data-shuffle="false">
  <video id="video1V" height="680px" controls data-caption="320 OGG" poster="videos/img/thumb1.jpg">
    <source src="videos/test_q_320" id="video1">Your browser does not support HTML5 video.
    </video>
  <video id="video2V" height="680px" controls data-caption="480 OGG" poster="videos/img/thumb2.jpg">
    <source id="video2" src="videos/test_q_480.ogg" id="video2">Your browser does not support HTML5 video.
    </video>
  <video id="video3V" height="680px" controls data-caption="1080 OGG" poster="videos/img/thumb3.jpg">
    <source id="video3" src="videos/test_q_1080.ogg" id="video3">Your browser does not support HTML5 video.
    </video>
</div>

这里是更改分辨率的代码(不在函数中时有效):

<script>
    function changeVidQualityFunction(){

    $chosenVidQuality = document.getElementById("selectQuality").value;
    $trulycompletevideolink = document.getElementById("video1").src;
    $step1 = document.getElementById("video1").src.split("_q_");
    //COMMENT: step1[0] is the url from start and including the first part of the filename (not the "_q_"-part and the format)
    $upToVidName = $step1[0];
    //COMMENT: step1[1] is the resolution and format, e.g. 320.ogg
    $step2 = $step1[1].split(".");
    //COMMENT: step2[0] is the resoltion e.g. 720 ,step2[1] is the format (without the dot in front of the format type) e.g. ogg
    $vidresolution = $step2[0];
    $vidformat = $step2[1];

        $vidresolution = $chosenVidQuality;
        $result = $upToVidName+"_q_"+$vidresolution+"."+$vidformat;
         $('#video1').attr('src', $result);
         $('#video1V').attr('data-caption', $vidresolution+" OGG");
         $('#video1V').load();

          window.alert("video1 attr src:"+document.getElementById("video1").src); //shows updated URL

}
          </script>

谢谢

Answer 1

在您的 head 上标记放置此 <script src="jquery-1.12.2.js" charset="utf-8"></script>包含 jquery 库，因为您使用的是 jquery 中的函数。 从这一行

<select id="selectQuality" onchange="changeVidQualityFunction()">

改成

<select id="selectQuality" name="video_selected">

并按照 jquery 的规则编辑您的脚本，按如下方式进行适当的声明。

function changeVidQualityFunction() {
        var ev = $('#selectQuality').val();
        console.log(ev);
    var chosenVidQuality       = $('#selectQuality').val();
    var trulycompletevideolink = document.getElementById("video1").src;
    var step1                  = document.getElementById("video1").src.split("_q_");
    //COMMENT: step1[0] is the url from start and including the first part of the filename (not the "_q_"-part and the format)
    var upToVidName            = step1[0];
    //COMMENT: step1[1] is the resolution and format, e.g. 320.ogg
    var step2                  = step1[1].split(".");
    //COMMENT: step2[0] is the resoltion e.g. 720 ,step2[1] is the format (without the dot in front of the format type) e.g. ogg
    var vidresolution = step2[0];
    var vidformat = step2[1];

        vidresolution = chosenVidQuality;
        var result = upToVidName + "_q_" + vidresolution + "." + vidformat;
         $('#video1').attr('src', result);
         $('#video1V').attr('data-caption', vidresolution+" OGG");
         $('#video1V').load();

      window.alert("video1 attr src:"+document.getElementById("video1").src); //shows updated URL

    }

注意我删除了 $尽管这是有效的，但还是用 var 声明它。所以 javascript 会知道它们是变量。

    $(document).ready(function(){
        $('#selectQuality').change(function(){
            changeVidQualityFunction();
        });
    });

代码的作用是，它会跟踪下拉菜单的变化，如果有变化，函数就会执行。

希望对你有帮助