CSS背景图像过渡使视频标签缓冲

Question

我有一个视频标签，我想连续播放，而用户可以同时在网站上进行操作。但是我发现，如果背景在背景图像之间转换，则视频将开始缓冲。我在下面的代码段中有一个可运行的示例。

注意：如果代码段正常运行，似乎不会发生缓冲，但是如果将代码段放入“整页”中，则会发生缓冲。

function changeBackground() {
  const randomColor = '#'+Math.floor(Math.random()*16777215).toString(16);
  const element = document.getElementById('background');
  const currentOpacity = element.style.opacity;
  const currentBackground = element.style.backgroundImage;
  
  switch (currentBackground) {
    case 'url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png")': {
      element.style.backgroundImage = 'url("https://i5.walmartimages.ca/images/Large/428/5_r/6000195494285_R.jpg")';
      break;
    }
    case 'url("https://i5.walmartimages.ca/images/Large/428/5_r/6000195494285_R.jpg")': {
      element.style.backgroundImage = 'url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png")';
      break;
    }
    default: {
      break;
    }
  }
}
 
 const element = document.getElementById('background');
 element.style.backgroundImage = 'url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png")'

#background {
  display: flex;
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: -10;
  
  background-size: contain;
  
  transition: background-image 3s ease-in-out;
}

#button {
  display: flex;
  width: 200px;
  height: 100px;
  background-color: orange;
  text-align: center;
}

#video {
  display: flex;
  position: absolute;
  top: 0;
  right: 0;
  width: 400px;
  height: 350px;
}

<div id='root' style='width: 100%; height: 500px'>
    <div id='background'></div>
    <div id='button' onClick="changeBackground()">Click me to change the background!</div>
    <video
      id='video'
      autoplay
      muted
      loop
      controls
      src="https://s3.amazonaws.com/codecademy-content/courses/React/react_video-cute.mp4"/>
</div>

可能是什么原因，有没有办法防止视频在仍具有背景图像过渡的情况下缓冲？

编辑：添加我在MacOS的Chrome上可能很重要。

编辑2：从我收集的答复来看，并不是每个人都可以重现该问题，因此我去了老式Windows PC并在那里进行了尝试。发现背景转换非常缓慢且缓慢，但是视频继续播放没有问题。它也可以在MacOS的Safari上运行，因此这似乎是Chrome MacOS专用的问题。

Answer 1

我必须承认我并不完全确定这里发生了什么...鉴于这不是 100% 重现的情况，也很难确定任何解决方法是否真正有效...

但这里有一些评论和想法。

似乎只有.mp4文件才会发生这种情况。我可以使用其他.mp4视频进行复制，但不能使用任何.webm文件进行复制。
因此，您可能想要尝试的一件事是在 webm 中重新编码您的视频，这可能是 Chrome 的 mp4 解码器存在一些问题。

CSS动画似乎不会导致此问题。因此，您可以将过渡代码重写为 CSS 动画，但主要问题是您无法在中间停止它（但无论如何，背景过渡似乎对此都很糟糕）。

function changeBackground() {
  const element = document.getElementById('background');
  if(element.classList.contains('apple')) {
    element.classList.remove('apple');
    element.classList.add('so');
  }
  else {
    element.classList.add('apple');
    element.classList.remove('so');
  }

}

#background {
  display: flex;
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: -10;
  
  background-size: contain;
  background-image: url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png");
}
#background.apple {
  animation: apple-to-SO 3s ease-in-out forwards;
}
#background.so {
  animation: SO-to-apple 3s ease-in-out forwards;
}
@keyframes apple-to-SO {
  from {
    background-image: url("https://i5.walmartimages.ca/images/Large/428/5_r/6000195494285_R.jpg")
  }
  to {
    background-image: url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png");
  }
}
@keyframes SO-to-apple {
  from {
    background-image: url("https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png");
  }
  to {
    background-image: url("https://i5.walmartimages.ca/images/Large/428/5_r/6000195494285_R.jpg")
  }
}

#button {
  display: flex;
  width: 200px;
  height: 100px;
  background-color: orange;
  text-align: center;
}

#video {
  display: flex;
  position: absolute;
  top: 0;
  right: 0;
  width: 400px;
  height: 350px;
}

<div id='root' style='width: 100%; height: 500px'>
    <div id='background'></div>
    <div id='button' onClick="changeBackground()">Click me to change the background!</div>
    <video
      id='video'
      autoplay
      muted
      loop
      controls
      src="https://s3.amazonaws.com/codecademy-content/courses/React/react_video-cute.mp4"/>
</div>

现在，如果您更喜欢 js 控制，那么 Web 动画似乎也不会受到影响。

let current = 1;
const urls = [
  "https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png",
  "https://i5.walmartimages.ca/images/Large/428/5_r/6000195494285_R.jpg"
];
function changeBackground() {
  const element = document.getElementById('background');
  element.animate({
      backgroundImage: ['url(' + urls[current] + ')', 'url(' + urls[+(!current)] + ')']
      }
    , {
      duration: 3000,
      iterations: 1,
      fill: 'both'
    }
  );
  current  = (current + 1) % 2;
}

#background {
  display: flex;
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: -10;
  
  background-size: contain;
  background-image: url(https://cdn.freebiesupply.com/logos/large/2x/stackoverflow-com-logo-png-transparent.png);
}


#button {
  display: flex;
  width: 200px;
  height: 100px;
  background-color: orange;
  text-align: center;
}

#video {
  display: flex;
  position: absolute;
  top: 0;
  right: 0;
  width: 400px;
  height: 350px;
}

<div id='root' style='width: 100%; height: 500px'>
    <div id='background'></div>
    <div id='button' onClick="changeBackground()">Click me to change the background!</div>
    <video
      id='video'
      autoplay
      muted
      loop
      controls
      src="https://s3.amazonaws.com/codecademy-content/courses/React/react_video-cute.mp4"/>
</div>