Changing videojs src with jquery and ajax

Im trying to use ajax and jquery to change src with videojs, so far i tried wrote this code

function getStream(response) {

var video =  $("#my-video")

$.ajax({
    type:'POST',
    url:'status.php?stream',
    data:{response:response},
    dataType: 'json',
    success:function(res){
    video.find('source').attr('src',res.stream);
    video.get().load();
    video.get().play();
   },
   error: function(jqXHR, textStatus, errorThrown){
  }
});

}

my html

                       <video
                             id="my-video"
                             class="video-js vjs-default-skin vjs-big-play-centered"
                             controls
                             preload="auto"
                             width="640"
                             height="264"
                             poster="images/enkwentro.jpg"
                             data-setup='{"fluid" : true, "techorder" : ["flash"]}'
                             >
                              <source id="source" src="" type="rtmp/mp4" />
                             <p class="vjs-no-js">
                                To view this video please enable JavaScript, and consider upgrading to a
                                web browser that supports HTML5 video
                             </p>
                          </video>

the video is not playing , note that the stream url is working and i tested it from server , but to set on src its not working, and when i directly put url in src in html, its working and no problem

thanks