How much bandwidth would Sirius Backseat TV use?
Friday, April 27, 2007 at 12:13 PM
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Long before Sirius Backseat TV was even announced, many a satrad geek has questioned how much bandwidth would be required to deliver the mobile video entertainment.
Well, the math-geniuses over at Satellite Radio TechWorld have a pretty darn good theory. Based on Sirius' response to a complaint filed by the WCS Coalition about Sirius Backseat TV, we learn that the video programming will use less than 1/5 of its bandwidth.
Now for some number crunching:
"So, we can calculate that [Sirius Backseat TV] will consume 2.5 MHz of the 12.5 MHz band, or 0.625 to 0.833 MHz per channel. Since it is broadcast on 3 carriers (two satellites and one repeater), the numbers have to be divided by 3, meaning that each channel per carrier will consume 208 to 278 KHz. If we understand the technology correctly, that should translate into video streaming somewhere on the order of 625 to 833 kbps per channel."
That might be our nearest indicator as to the level of quality to expect for the service. The demo at CES looked pretty damn good, though that could have been, well, just a demo.
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Comments
So will this affect the sound quality at all??
Posted by: XMfanatic ? | April 27, 2007 12:39 PM
Will this affect the Sound quality on the Music channels at all??
Posted by: XMfanatic ? | April 27, 2007 12:42 PM
XMfanatic- I don't believe so. Its my understanding that Sirius has already allocated for this bandwidth. However, an argument could be made that Sirius' music channels could sound even better than they do now if they didn't do this...
Posted by: rjr | April 27, 2007 12:54 PM
1/5 is huge and should hurt the audio channels -- if it did not, you would think the overall SQ would be better. A 20% reduction in BW for the audio channels will not go over well.
Posted by: iband | April 27, 2007 1:22 PM
I personally feel that the bandwidth for this deal has been set aside for some time. This really is the same type of thing as XM weather, though that service is much more practical in my mind.
My guess, the SQ impact has already been felt.
Posted by: dualsub2006 | April 27, 2007 1:22 PM
"That might be our nearest indicator as to the level of quality to expect for the service."
Sirius had Sirius Tv playing at the NY auto show this year in a few different places. it was not a demo disc, it was live! sound and picture quality were excellent.
You claim you're unbaised, yet that shot against quality once again shows who you really are biased towards.
Posted by: Philmore | April 27, 2007 6:57 PM
Wait... didn't I say that the demo at CES looked damn good? How is that a shot against quality?
Posted by: Ryan Saghir ? | April 27, 2007 9:32 PM
"Wait... didn't I say that the demo at CES looked damn good? How is that a shot against quality?"
because you followed it up with...
"though that could have been, well, just a demo"
you were implying the quality "looked damn good" because it was "well, just a demo."
Posted by: Philmore | April 27, 2007 9:54 PM
Ryan I have no idea how Philmore could claim you are biased against Sirius when you are for the merger.
Who was pushing for this merger for just about forever? Mel.
Also, as a Sirius sub I stand by my opinion that Backseat Video is going to be just as successful as "NEW" Coke.
Posted by: History Guy ? | April 28, 2007 12:01 PM
There are supposed to be what, up to five video channels all together?? And from what I've heard they are all little kid programming, like Disney or cartoon network.. So why is everybody so excited about this? what is the big hairy deal here?? sorry I can't get excited about this service, and I know XM is developing the same b.s. for their subs.. I shake my head at this and wonder why.. just like the merger..
Posted by: steve | April 29, 2007 8:27 PM
steve...
and that why you are not a business man or working for sirius/xm.
The childrens' market is one of the bigest markets out their. Just check IMDB's top 50 and youll see the highest grossed movies are children related. Plus it opens doors for other channels carrying video.
Is it possible to create a new compression scheme?
Posted by: dave | April 30, 2007 11:50 AM
Philmore: Not for nothing, but the demo really was... just a demo. The majority of things we see at CES are put together the night before with ducttape and glue. So if I took it at face value, I would be fooling myself.
The thing is, 1/5th of their bandwidth is actually quite a big chunk in my opinion. So the quality will likely be very high. But compression schemes can vary and the only way to judge the quality is by seeing the product, in its final form. Trust me, with two little kids myself, I'd be more than happy to subscribe to Sirius Backseat TV.
But I think you're trying to find bias where there is none. I'm a huge supporter of both services, but I'm also not going to be a pom-pom waving cheerleader either.
Posted by: Ryan Saghir ? | April 30, 2007 4:29 PM
Thank God it's only 1/5th. I was concerned that it could be 20%.
Now I'm relieved.
Posted by: Pockpie Hates War | April 30, 2007 5:27 PM