Created by Wang, Jerry, last modified on Mar 01, 2016
how is __metadata.media_src generated in backend 
how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend how is __metadata.media_src generated in backend 
