Tata Sky DTH is now providing a new Set Top Box to the customers.
This new STB is compatible with MPEG4 technology though the current feed remains in MPEG2.
Tata Sky Plus DTH is already MPEG4 compatible.
The company cannot shift to MPEG4 broadcast just like that because millions of their existing customers are still using the older generation STB model which does not support this standard.
Tata Sky is probably hoping that in a year or two, most of their existing customers would upgrade to this new set top box enabling them to switch to the more efficient broadcasting standard.