This is just based off of previous knowledge, which means I may be wrong. But I'll take a stab at it and share my ideas.
The IS1 and the I2 will render graphics in real time. Unlike the XL, there is no "pre-rendering" with the graphics. Technically, every STAR rendered in real time except for the XL due to TWC's in house presentation engine. Cool concept at the time, but the XL got a little messy and isn't the most efficient in a number of ways (although it still is one of my favorites). The IS1 used an in-house presentation engine from TWC.
You are correct with the I2 using the Viz Engine... absolutely no question about it, and it does use the XML format to process data. I have reason to suspect that the version of Viz Engine that TWC utilized on the I2 was customized explicitly for TWCs vision, and isn't exactly back compatible with your typical Viz ecosystem. This isn't proven, but it is a theory that I think is viable. If people are concerned about the costs of TWC getting customized software like this... it's likely chump change to them in my opinion.
As far as the satellite communication goes, there is no talking back to the transponder. What TWC beams up to their transponder is the only thing that is going through that transponder; there is no talking back, again. This is where I believe that Viz Engine is capable of running stand alone without any other equipment in the headen. This may only work if the STAR is authorized by TWC through the back channel (ethernet connection that talks back to TWCs servers). My disclaimer with this idea is that the STAR may be capable of running without calling TWC to activate it as long as data is properly flowing from the IRD/descrambler (which typically needs authorization from TWC). It should also be noted that data isn't transmitted to the STAR over the internet, except for SCMT (Star Configuration Management Tool) information. It should be noted that SCMT can't be accessed by anyone other than a headend tech as it is password protected.
I do have two questions, however.
- How did you come up with the $8000 price tag? If you are talking about machines that Viz is dependent on, it will not cost a headend that much money as the headend doesn't need this equipment. As far as things at TWC HQ, I wouldn't know. I'm sure they've invested hundreds of thousands into development. As far as the headend goes... I'd be floored if it costs anything over $700 to be honest.
- Two motherboards? The IS1, I2HD and I2Jr all have daughter boards that the software is dependent on. The I2XD is the exception with the complicated graphics processing as it appears to be using MPEG video streams that is sent down through the IRD/descrambler. What do you mean by two motherboards?
