>>> Which version of PAC are you using as your baseline for comparIson? What about Statistical Multiplexing? You did add that into your calculations? Didn't you?
Don't need to. Stat/mux is about allocating bandwidth, not about digital compression. There is still the same amount of bandwidth available. Yes, it is true that when all channels in a cluster are demanding minimal bandwidth, that cluster will have excess capacity -- but it goes essentially un-utilized, just as the excess does when XM allocates 40kb/s to a channel that is momentarily needing 0kb/s.
The flip side, which is the bigger problem, is that when all channels in a cluster are at peak demand using stat/muxing, you end up with insufficient bandwidth to accommodate them all, and sound quality is adversely affected. Stat/muxing is a choice of how to allocate the bandwidth that is available at any given instant -- SIRI chose stat/muxing which effectively allows a computer to "decide" how to allocate it, whereas XM places absolute limits on a per-channel basis.
All that can be said about stat/muxing is that it is a "different" way of doing things that sometimes provides efficiency at the expense of sound quality while XM's allocations allow them to control min/max per channel at all times. The results are different, but each has its plusses and minuses. Any added throughput SIRI gains by using it is compromised by the occasional drops in sound quality during those times when all channels in a cluster are at peak demand. They must, therefore, allocate sufficient bandwidth to the cluster to provide reasonable sound quality on all the channels almost all of the time; otherwise, the risk of drops in sound quality destroying the overall product are too great.
I have no opinion as to which is "better", only that they are "different".
>>> More OPINONS presented as FACTS?
Provide a post proving that any other significant entity is using PAC.
>>> Maybe you can explain how they are doing video channels with those lower link budgets?
They aren't -- yet. But when they do, remember they'll be channels of CARTOONS which can be highly compressed without significant degradation. You won't be watching football games on SIRI's "video", I don't believe -- and were it to happen, the video would be lousy. At the same time, if they want to allocate ALL of their HM gains to 3 channels of video, perhaps they can carve out one channel of decent video, if you use a small enough screen LOL.
>>> Hey, I am not the one posting MY OPINIONS as FACTS!
Let's see you provide links contradicting anything I've said, and links SUPPORTING what YOU have said. You're FOS. |
