.holdervideo iframe {
  display: inline-block;
  width: 420px;
  height: 250px;
}
.carouselvideo {

  width: 100%;
  height: 250px;
  overflow: hidden;
  box-sizing: border-box;
  border: 1px solid #999;
  margin: 0 auto;
  border-radius: 5px;
}
.holdervideo {
  -webkit-animation: carousel 90s linear infinite;
          animation: carousel 90s linear infinite;
  white-space: nowrap;
  will-change: transform;
}
@-webkit-keyframes carousel {
  0% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
  }
  50% {
    -webkit-transform: translateX(-100%);
            transform: translateX(-100%);
  }
  100% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
  }
}
@keyframes carousel {
  0% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
  }
  50% {
    -webkit-transform: translateX(-100%);
            transform: translateX(-100%);
  }
  100% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
  }
}