#video-container {
    position:relative;
    width: 100%;
    height: 0px;
    padding-bottom: 56%; /* proportional scaling */
    padding-top: 50px; /* add constant */
}

#video-container object {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
}

https://stackoverflow.com/questions/14161321/scaling-object-element-height-proportional-to-width-constant-with-css