- 当前 Bug 的表现（可附上截图）

视频在手机客户端上面播放，几秒种后就会出现卡顿现象

- 预期表现

正常播放不卡顿

- 复现路径

<video bindtimeupdate="bindtimeupdate" id="myVideo" objectFit="contain" style='width:750rpx;height:423rpx;position:fixed;top:{{height}}px;left:0;z-index:9999999;' src="{{detail.video}}" custom-cache="{{false}}" controls show-center-play-btn="{{!show}}" poster='../../images/backfg.png' direction="{{90}}"

bindplay="bindplay" bindpause="bindpause" bindended="bindended" bindfullscreenchange="bindfullscreenchange" autoplay="{{autoplay}}">

<cover-view class="controls" style="{{'position:fixed;top:{{height}}px;;left:0;width:750rpx;height:423rpx;line-height:423rpx;background:#fff;position:fixed;left:0;' + (show ? 'display: block' : 'display: none' )}}" bindtap="play">

<cover-image style='width:750rpx;height:390rpx;position:absolute;top:0;left:0;z-index:3;' src="{{detail.image}}" />

<cover-view class="play" style='width:106rpx;height:106rpx;position:relative;z-index:5;top:50%;left:50%;margin-top:-53rpx;margin-left:-53rpx;'>

<cover-image class="imga" style='display:inline-block;' src="https://zxhealthoss.oss-cn-beijing.aliyuncs.com/resource/recommend/bofanx.png" />

</cover-view>

</cover-view>

<cover-view class="screenBtn" bindtap="screen" style="{{screenBtnShow ? 'display: block' : 'display: none'}}">

<cover-view>

<cover-image src="http://static.superkangaroo.net/resource/recommend/shouzhi_icon.png"></cover-image>

</cover-view>

<cover-view>全屏播放</cover-view>

</cover-view>

</video>

- 提供一个最简复现 Demo

https://static2.superkangaroo.net////////uploads/2018/12/5/23075025606194087.mp4