Понравился вот такой CSS-эффект для кнопки воспроизведения.

HTML:

<div class="button-sonar">
<a href="#" class="hi-icon video-play-btn"><i class="fa fa-play" aria-hidden="true"></i></a>
</div>

CSS:

.button-sonar {
  position: absolute;
  top: 50%;
  right: 65px;
  z-index: 99;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%); }
  @media only screen and (min-width: 768px) and (max-width: 991px) {
    .button-sonar {
      right: auto;
      left: 50%;
      -webkit-transform: translate(-50%, -50%);
      -ms-transform: translate(-50%, -50%);
      transform: translate(-50%, -50%); } }
  @media only screen and (max-width: 767px) {
    .button-sonar {
      right: auto;
      left: 50%;
      -webkit-transform: translate(-50%, -50%);
      -ms-transform: translate(-50%, -50%);
      transform: translate(-50%, -50%); } }
  .button-sonar .video-play-btn {
    display: inline-block;
    border-radius: 50%;
    width: 70px;
    height: 70px;
    background-color: #1583e9;
    color: #ffffff;
    line-height: 70px;
    text-align: center;
    font-size: 24px; }
    .button-sonar .video-play-btn i {
      padding-left: 5px; }
    .button-sonar .video-play-btn:focus, .button-sonar .video-play-btn:hover {
      box-shadow: none;
      background-color: #1583e9; }

.button-sonar .video-play-btn {
  -webkit-transform: scale(0.93);
  -ms-transform: scale(0.93);
  transform: scale(0.93); }
  .button-sonar .video-play-btn:after {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    content: '';
    -webkit-box-sizing: content-box;
    -moz-box-sizing: content-box;
    box-sizing: content-box;
    top: 0;
    left: 0;
    padding: 0;
    z-index: -1;
    box-shadow: 0 0 0 2px #1583e9;
    opacity: 1;
    -webkit-transform: scale(0.9);
    -ms-transform: scale(0.9);
    transform: scale(0.9);
    -webkit-animation: sonarEffect 1.3s ease-out 75ms infinite;
    animation: sonarEffect 1.3s ease-out 75ms infinite; }

@-webkit-keyframes sonarEffect {
  0% {
    opacity: 0.3; }
  40% {
    opacity: 0.5;
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5); }
  100% {
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5);
    transform: scale(1.5);
    opacity: 0; } }
@-moz-keyframes sonarEffect {
  0% {
    opacity: 0.3; }
  40% {
    opacity: 0.5;
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5); }
  100% {
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5);
    transform: scale(1.5);
    opacity: 0; } }
@keyframes sonarEffect {
  0% {
    opacity: 0.3; }
  40% {
    opacity: 0.5;
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5); }
  100% {
    box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.1), 0 0 10px 10px #3851bc, 0 0 0 10px rgba(255, 255, 255, 0.5);
    transform: scale(1.5);
    opacity: 0; } }