Responsive video background: Video alignment - html

Question

I want to create a responsive background video, but don't know how to change the alignment.
As far as I can see, the alignment currently is bottom right, but I want to change it to center center. (like background-position: center center)
Is there any way to achieve this?
Fiddle: http://jsfiddle.net/66dLhjxh/
HTML:
<video autoplay loop poster="http://demosthenes.info/assets/images/polina.jpg" id="bgvid">
<source src="http://demosthenes.info/assets/videos/polina.webm" type="video/webm">
<source src="http://demosthenes.info/assets/videos/polina.mp4" type="video/mp4">
</video>
CSS:
video {
position: fixed;
display:block;
right: 0;
bottom: 0;
min-width: 100%;
min-height: 100%;
width: auto;
height: auto;
z-index: -100;
background-color:#fff;
background:url(../img/schrijven.jpg) no-repeat;
background-size: cover;
background-position: center center;
}

Answer 1

try this code DEMO
<div id="info">
Responsive Youtube embed......
</div>
<div class="holder">
<div class="video-container">
</div>
</div>
<button onclick="nextVideo()">Next Video</button>
</div>
.video-container {
position: relative;
padding-bottom: 56.25%; /* 16:9 */
padding-top: 30px; /* size of chrome */
height: 0;
overflow: hidden;
}
.video-container iframe,
.video-container object,
.video-container #overlay,
.video-container embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
#overlay {
background:#000;
opacity:0.5;
/*background:rgba(255,255,255,0.8); or just this*/
z-index:50;
color:#fff;
}

Answer 2

with this is perfect
video {
position: fixed;
display:block;
right: 0;
bottom: 0;
min-width: 100%;
min-height: 100%;
width: auto;
height: auto;
z-index: -100;
background-color:#fff;
background:url(../img/schrijven.jpg) no-repeat;
top: 0px;
left: 0px;
background-size: cover;
background-position: 50% 50%;
/*background-position: 30% 50%;*/
}
See it in action.