VideoAngular Angualr js

Binding to vg-src – How come this works:

     <vg-next-video vg-src="'data/media-files.json'" vg-time="3000"></vg-next-video>

data/media-files.json Content:

   [
      [
       {
      "src": "http://static.videogular.com/assets/videos/videogular.mp4",
      "type": "video/mp4"
    },
    {
      "src": "http://static.videogular.com/assets/videos/videogular.webm",
      "type": "video/webm"
    }
      ],
      [
       {"src": "http://static.videogular.com/assets/videos/big_buck_bunny_720p_h264.mov", "type": "video/mp4"},
    {"src": "http://static.videogular.com/assets/videos/big_buck_bunny_720p_stereo.ogg", "type": "video/ogg"}
      ]
   ]

But when I set a scope to

 $scope.testVideos  =  [
          [
           {
          "src": "http://static.videogular.com/assets/videos/videogular.mp4",
          "type": "video/mp4"
        },
        {
          "src": "http://static.videogular.com/assets/videos/videogular.webm",
          "type": "video/webm"
        }
          ],
          [
           {"src": "http://static.videogular.com/assets/videos/big_buck_bunny_720p_h264.mov", "type": "video/mp4"},
        {"src": "http://static.videogular.com/assets/videos/big_buck_bunny_720p_stereo.ogg", "type": "video/ogg"}
          ]
       ]

and set vg-src=”testVideos” like below, it does not work( the video does not play)

 <vg-next-video vg-src="testVideos" vg-time="3000"></vg-next-video>

I am using Videoangular for angular js. What do I need to do to make the $scope.testVideos work. Isn’t the two data the same? I have omitted some code to keep it short but my only concern is the setting of vg-src. A

Source: AngularJS