Here are some links to get access to Dolby Digital Plus content
Video Streams (mp4, HLS, MPEG-Dash, Smooth)
http://developer.dolby.com/support.aspx#video
For Dolby Digital Plus Sound Effects we have a sound pack that we've put together for use as well:
http://developerdownload.dolby.com/sound_files/pack_001/sound_pack_001.zip