An update: Apart from the HD channels that I mentioned in the first post that have the picture quality impacted by compression, I checked other HD channels that were earlier not part of "TN Silver HD" pack. The picture quality of channels like Star Plus HD, Zee TV HD, Sony TV HD and Colors Cineplex HD are on par with the picture quality of Sun TV HD at LCN 800. But picture quality of the HD channels like Asianet HD, Zee Telugu HD, Zee Kannada HD, Colors Marathi HD, Star Maa HD etc. are not up to the mark when compared to a benchmark HD standard and I saw the same defects like blurriness or graininess in the long distance shots and edge artefacts on the actors moving in those long distance shots i.e. same issue that I found in HD channels like Star Vijay HD, MTV Beats HD, Animal Planet HD, Sun Music HD, etc.
Mail to the Nodal Team: Then I sent a mail to the Sun Direct's Nodal team with the content similar to the one in my first post of this thread and received a call the next day itself and they requested to allow a technician's visit. I told them that this issue did not require a technician visit since it needs to be rectified at the back-end. But they insisted that they need to follow a protocol to make sure that everything is fine at the customer's end and then I accepted the request. The technician came and checked everything right from the signal strength and quality and even measured the dimensions of the room where the TV is placed and said he did not find any problem in hardware from the customer's end.
Then I showed him what the issue is through the following channels.
1.) Showed the difference in the picture quality of Sun TV HD in the HD Info channel at LCN 005 and Sun TV HD at LCN 800. The HD Info channel Sun TV HD has the defects like blurriness or graininess in the long distance shots and edge artefacts on the faces of actors moving in those long distance shots whereas Sun TV HD at LCN 800 is perfect without those issues.
2.) Showed him the channels like Asianet HD, Zee Telugu HD and Zee Kannada HD having the same issue as mentioned above.
3.) Showed him Bigg Boss Tamil S5 on Star Vijay HD at LCN 803 which has the same blurriness issue and edge artefacts and also showed the same program without any flaw in the Airtel HD set-top-box connected through the another HDMI slot of the same TV.
The other marker through which one can easily find the issue is to look at the graphics theme of Star Vijay HD as shown below. When you look keenly by being closer to the TV, you can see those very light white lines perfectly in both Airtel HD and Tata Sky HD without any graininess but the same cannot be found in Sun Direct HD because the edges get disoriented due to compression and hence only graininess could be found as a pattern during the telecast. You can also look at Mr. Kamal Haasan's face while walking during every advertisement break and will not even identify his face clearly.
The technician acknowledged the differences that I have shown in the above HD channels. Since he is from the front-end support system, he could not understand the exact technical reason for the same but assured me that he would convey the differences in the HD channels to the Nodal team. Then I received a call from the Nodal team and they said that the technician did not find any issues related to hardware at my end and wanted to close the complaint. They further stated that they would share my 'feedback' (not an 'issue' according to them!) to the back-end technical team for an appropriate review but this statement during the conversation did not inspire much confidence.
I do not have much hope further that this process would lead to a logical conclusion. I believe this is a conscious decision taken by the Sun Direct's technical team to limit the bandwidth to HD channels similar to the decision to compress and homogenize the audio quality of HD channels to save bandwidth for the lack of Transponders. But how long are the going to do this? Once they get the enough transponders, will they improve the audio and video quality of HD channels or would that remain the same since many customers did not raise an issue? They need to realise that this decision is impacting both the HD video clarity and audio quality and those customers that expect flawless video and audio quality will be surely disappointed by this decision.
With a much transparent watermark on HD channels for good viewing experience when compared to all the other HD DTH operators that place their opaque logos, Sun Direct can reign supreme if they provide flawless HD audio and video quality using the HEVC compression technology to their advantage. But this aspect is missing currently!