Chrome不尊重视频源内联媒体查询

Question

使用以下内容,Chrome不会尊重媒体查询,以根据设备宽度显示正确的视频源.Chrome正在播放它找到的第一个来源,你可以在这里看到:http://homeglobal.ch/.我怎样才能解决这个问题？

    <video id="intro-video" poster="img/poster.png" controls>
        <source src="videos/intro.mp4" type="video/mp4" media="all and (min-device-width:1600px)">
        <source src="videos/intro.webm" type="video/webm" media="all and (min-device-width:1600px)">
        <source src="videos/intro-1600.mp4" type="video/mp4" media="all and (min-device-width:1100px)">
        <source src="videos/intro-1600.webm" type="video/webm" media="all and (min-device-width:1100px)">
        <source src="videos/intro-1100.mp4" type="video/mp4" media="all and (min-device-width:481px)">
        <source src="videos/intro-1100.webm" type="video/webm" media="all and (min-device-width:481px)">
        <source src="videos/intro-480.mp4" type="video/mp4">
        <source src="videos/intro-480.webm" type="video/webm">
    </video>

Answer 1

不幸的是,Chrome不支持视频html 5标签的媒体查询.解决这个问题的方法是使用普通的Javascript或Jquery.它不漂亮,但即使在chrome中也能正常工作.

var video = $('#myvideo');

var WindowWidth = $(window).width();

if (WindowWidth < 1200) {
    //It is a small screen
    video.append("<source src='/img/homepage/640/splash.m4v' type='video/mp4' >");
} else {
    //It is a big screen or desktop
    video.append("<source src='/img/homepage/1080/uimain-1080.mp4' type='video/mp4' >");
}

Answer 2

我在 Vanilla JS 上的实现。

在video标签中，作为data-src属性，指定默认视频的路径。在标签内部video，在标签中，我们指定和source两个属性的值。data-srcdata-mw

data-src- 是视频文件的路径。

data-mw- 是显示该视频的最大屏幕宽度。

当屏幕宽度改变时，该解决方案会自动工作。这是使用该resize()函数完成的。

<video id="intro-video" data-src="/path/default.mp4" poster="img/poster.png" controls>
    <source data-src="/path/1600.mp4" data-mw="1600">
    <source data-src="/path/900.mp4" data-mw="900">
    <source data-src="/path/480.mp4" data-mw="480">
</video>

class VideoResponser {
    constructor(selector) {
        const $video = document.querySelector(selector);
        this.options = { 
            selector, 
            breakpoints: { default: { src: $video.getAttribute('data-src') } } 
        };

        // get a list of video switching points and links to the videos themselves 
        $video.querySelectorAll('[data-src]').forEach(element => this.options.breakpoints[element.getAttribute('data-mw')] = { src: element.getAttribute('data-src') });
        $video.innerHTML = ''; // we clean up so that there is nothing superfluous 
        
        // run the handler and track the change in screen width
        this.responseVideo(this.options);
        this.resizer();
    }

    /** Function runs on resize  */
    resizer() {
        window.addEventListener("resize", () => this.responseVideo(this.options));
    }

    /** 
     * Change src value of video link to fit screen width 
     * 
     * @param {Object} options object with options 
     */
    responseVideo(options) {
        const {selector, breakpoints} = options; // get options
        let $video = document.querySelector(selector);
        const widthNow = $video.getAttribute('data-width-now') || null;
        const maxBreakpoint = Math.max.apply(Math, Object.keys(breakpoints).filter(key => key <= document.body.clientWidth).map(Number));
        const nowBreakpoint = maxBreakpoint || 'default'; // choose either the maximum value, if not, then the default 

        if(widthNow && widthNow == nowBreakpoint) return; // check if the video needs to be changed 

        $video.setAttribute('data-width-now', nowBreakpoint);
        $video.src = breakpoints[nowBreakpoint].src;
    }
}

new VideoResponser("#intro-video");