Bootstrap 3 and Youtube in Modal

I found this problem (or the problem I found and described at https://github.com/twbs/bootstrap/issues/10489) related to CSS3 transformation (translation) on the .modal.fade .modal-dialog class.

In bootstrap.css you will find the lines shown below:

.modal.fade .modal-dialog {
  -webkit-transform: translate(0, -25%);
      -ms-transform: translate(0, -25%);
          transform: translate(0, -25%);
  -webkit-transition: -webkit-transform 0.3s ease-out;
     -moz-transition: -moz-transform 0.3s ease-out;
       -o-transition: -o-transform 0.3s ease-out;
          transition: transform 0.3s ease-out;
}

.modal.in .modal-dialog {
  -webkit-transform: translate(0, 0);
      -ms-transform: translate(0, 0);
          transform: translate(0, 0);
}

Replacing these lines with the following will show the movie correctly (in my case):

.modal.fade .modal-dialog {
  -webkit-transition: -webkit-transform 0.3s ease-out;
     -moz-transition: -moz-transform 0.3s ease-out;
       -o-transition: -o-transform 0.3s ease-out;
          transition: transform 0.3s ease-out;
}

.modal.in .modal-dialog {

}