宽高比(移动端)

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <title>Document</title>
<style>
* {
box-sizing: border-box;
}

.section-video ul.list {
padding: 5px;
width: 100%;
font-size: 12px;
background-color: #0363b5;
list-style: none;
overflow: hidden;
}

.section-video ul.list li {
display: inline-block;
width: 50%;
padding: 5px;
float: left;
}

.section-video ul.list li a {
display: block;
width: 100%;
color: #fff;
text-decoration: none;
}

.section-video ul.list li .img {
width: 100%;
position: relative;/* 使用相对定位*/
height: 0;/*高度设置为0，使用padding来设置高度*/
overflow: hidden;
/*padding-bottom: 54.545454%;*/ /*使用padding-top也可，使用padding来撑高容器，高度为宽度的 54.545454%*/
padding-bottom: 56.25%;
}

.section-video ul.list li .img img {
position: absolute;/*使用绝对定位*/
width: 100%;/*宽高为容器的宽高*/
height: 100%;
top: 0;
left: 0;
    text-align:center;display:table-cell;vertical-align:middle;
}

.section-video ul.list li .img .time {
position: absolute;
display: inline-block;
right: 0;
bottom: 15px;
font-size: 12px;
line-height: 18px;
background-color: rgba(0, 0, 0, .48);
border-top-left-radius: 8px;
border-bottom-left-radius: 8px;
padding: 0 10px;
}

.section-video ul.list li .title {
display: block;
line-height: 18px;
padding: 4px 0;
height: 40px;
overflow: hidden;
text-overflow: ellipsis;
}
</style>
</head>
<body>
<div class="section-video">
    <ul class="list">
        <li>
            <a href="javascript:void(0)">
                <div class="img">
                    <!--<img src="3.png" alt=""/>-->
                    <img src="http://down2.9apps.com:7080/group1/M01/76/E4/poYBAFdlMBmAKGmxAAA7r722CEs285.jpg"  alt="logo"/>
                    <span class="time">07:12</span>
                </div>
                <span class="title">我是标题</span>
            </a>
        </li>
        <li>
            <a href="javascript:void(0)">
                <div class="img">
                    <img src="http://down2.9apps.com:7080/group1/M01/76/E4/poYBAFdlMBmAKGmxAAA7r722CEs285.jpg" alt="logo"/>
                    <span class="time">04:58</span>
                </div>
                <span class="title">我是标题</span>
            </a>
        </li>
        <li>
            <a href="javascript:void(0)">
                <div class="img">
                    <img class="" src="http://down2.9apps.com:7080/group1/M01/76/E4/poYBAFdlMBmAKGmxAAA7r722CEs285.jpg" alt="logo">
                    <span class="time">03:54</span>
                </div>
                <span class="title">我是标题</span>
            </a>
        </li>
        <li>
            <a href="javascript:void(0)">
                <div class="img">
                    <img class="" src="http://down2.9apps.com:7080/group1/M00/76/E4/pYYBAFdlMBuAO13wAAA-uPs5iqo997.jpg" alt="logo">
                    <span class="time">03:14</span>
                </div>
                <span class="title">我是标题</span>
            </a>
        </li>
    </ul>
</div>
</body>
</html>
效果图：