Some video streaming apps use Dolby Digital Plus (DD+/E-AC-3) to send 5.1 multi-channel audio to your TV or audio/video receiver. The SHIELD TV passes the bitstream audio to your TV or receiver over HDMI. If your TV or receiver cannot decode Dolby Digital Plus, you will not get any audio when streaming content using Dolby Digital Plus. To check which audio formats the device connected to your SHIELD TV supports, go to SHIELD TV Settings -> About -> Status -> HDMI -> Audio mode. It will display all of the audio modes that the SHIELD TV detects as shown in the image below.
The TV or audio receivers supported audio formats are sent to the SHIELD TV when it is connected over HDMI. If the SHIELD TV Surround setting is set to AUTO and the device it is connected to cannot decode Dolby Digital Plus, the SHIELD TV will not send the audio in surround Dolby Digital Plus format. Some devices will incorrectly advertise Dolby Digital Plus support to the SHIELD TV even though it cannot decode this format. To workaround this issue, go to the SHIELD TV Settings -> Display & Sound -> Advanced Settings -> Surround sound -> change from Auto or Always to Never to force stereo mode.