Hi GowriShankar,
I have recently installed Tata Sky Binge + box in my home and connecting my home theatre from Binge+ box via Optical port for Audio. I am getting 5.1 Audio for HD Channels. But not getting 5.1 for Binge+ apps (ex: Amazon Prime, Sun Next, Hot Start, Zee5..etc). I was chasing with customer care and technician, technician visited and told me that as per the agreement between binge+ apps and Tata sky, set of box will support only 2.1 for apps. But I called Amazon Prime customer care and they told me that, that technician's statement is false. Thus, Again I raised the complaint in Tata Sky to get this agreement level info from Management, waiting for the call. I will let you know once I got the info.
Note:
You should get 5.1 for channels. Actually, All HD Channels are not 5.1, few HD channels only supports 5.1. For example, if you take the Tamil Channels Sun Music HD, Sun TV HD, Zee Tamil HD, Colors TV HD Star Vijay Tamil HD, and KT HD. But out of these channels, Sun Music HD and Sun TV HD only is giving real 5.1 audio. Morever, some time if old/middle songs playing in Sun Music HD also not 5.1. But most of the TV Serials in Sun TV also giving 5.1 audio. In this case, if you want to check your 5.1 audio with your home theatre, you can use Sun TV HD channel to check your Audio.
After playing channels some time 5.1 audio works after you changed the sound settings as below.
Step: You need to go to Sound Settings in your Binge+ box and change the mode as "None : Never use surround..etc" after then select "Auto option" Then only your set of box is refreshing and giving 5.1 audio (not always giving).