video全面屏播放后 视频就很慢 是什么原因？

<video id="myVideo"></video>

onReady(res) {
let _this = this;
// this.videoContext = uni.createVideoContext('myVideo',this);
// // console.log(JSON.stringify(_this.videoContext))
// this.videoContext.requestFullScreen();
let aa = plus.video.createVideoPlayer('myVideo', {
src: _this.videoUrl,
direction: 90,
duration: 1000,
controls: false,
autoplay: true,
muted: false,
"show-loading": false,
"show-progress": false,
"show-fullscreen-btn": false,
objectFit: "cover"
});
var currentWebview = this.$scope.$getAppWebview()
currentWebview.append(aa)

    },