Super Bowl Bandwidth?

[summerfun]

I saw a string of messages talking about the added bandwidth channel 58 was going to give to the Super Bowl. They were going to shut down some of their multicasting and give more bandwidth to the Super Bowl.

I understand how bandwidth works for computer networks and more bandwidth allows more people to communicate, but they are broadcasting OTA.

What does it mean to give more bandwidth to a broadcast OTA? People are not watching on a network. The broadcast should not be effected by an increased number of OTA receivers. Should it?

TWC picks up the OTA signal and sends it out over their own cable network, so that would not be a factor. Would it?

Why does the Super Bowl need more bandwidth?

Is it a quality issue? If so, do they not always send out their best quality? How does bandwidth effect quality and how do we know when we are getting the best quality? Should we not always expect the best quality?

I thought digital was always 100%. It is either there or not there. No in between.

[StarvingForHDTV]

I'm not an expert, but this is my understanding.

Digitial TV is sent out as a stream of information.  This stream is something like 19 MB per second or ??  Stations have the choice to devote that full amount of information to one channel, or to divide it up and send out multiple channels in that same stream.

When multiple channels are used (1-1,1-2,1-3) or (10-1,10-2,10-3,10-4,10-5,etc) each channel is allocated a certain amount of the total bandwidth available.  If this number is low, you will see "blocking" and other strange things which make the picture appear much lower quality.

With High Definiton, the bandwidth needs are greater.  With HD sports, the bandwidth needs are fairly large.  If you devote too little of the available bandwidth, the HD sports don't look as good as they should.

I hope this helps,

Starving

[summerfun]

Maybe I don't fully understand multi casting because I use TWC and not OTA.

Are you saying that all of the programming for Channel 58 comes across in one data stream and then your receiver box must split them into separate channels? If that is the case, are those other programs available to everyone or only those watching OTA? What kind of programming is it?

If they felt the need to shut down some of the multi casting channels to gave more bandwidth to the Super Bowl, does that mean that we do not normally get the best quality HD for other CBS shows? In other words, can they turn up or down the HD quality of the signal being broadcast by allocating more or less bandwidth?

[Gregg Lengling]

Well first off the bandwidth does matter even if you are receiving 58 thru Warner as they get their signal from them over the air...so you are seeing the same thing.

There are 3 stations multicasting right now.
Channel 58 runs 3 streams (more during March madness)
1.1 is 58 in HD
1.2 is WMLW (low power 41 of Milwaukee)
1.2 is Channel 63 (telemundo, spanish channel)

Channel 10 runs 5 streams
10.1 Channel 10 3 hour delay
10.2 Channel 36 3 hour delay
10.3 PBS Kids
10.4 PBSU
10.5 Weather screen with Classical Music

Channel 18 runs 2 streams
18.1 Analog rebroadcast of 18
18.2 HD color bar test signal.

They have to apply said amount of bandwith to each program, and in 58's case they apply a large majority to 1.1 to allow for HD programming and a lesser amount to each of 1.2 and 1.3 as these are only SD programs.

With compression they can provide this in the bandwith of their channel...however with compression comes the possibility of errors which show up as pixelation and artifacting.  So when the Superbowl was on over the weekend they improved the bandwith for 1.1 by reducing the bandwith allocated to 1.2 and actually shut of 1.3 for the weekend.

This is a basic primer and I hope it helps you...so you can see you may be getting some of the digital channels from TWC but you aren't getting everything that is available as those with OTA tuners have the options of seeing all these other hidden programs.

[veyj]

If TWC is using OTA for the 58 and 41 feeds, they must be using analog 41 instead of 1-2 (46-2).  When the bandwidth is reduced, that channel looks terrrible.

Is the following table accurate?

OTA     TWC

58          5      TWC uses analog 58 for the feed
41          7      TWC uses analog 41 for the feed
63          ?       ?
1-1     505      TWC uses 1-1 for the feed
1-2         ?       Digital 41 does not exist at TWC
1-3         ?       Digital 63 does not exist at TWC
1-4         ?       NCAA March Madness
1-5         ?       NCAA March Madness
1-6         ?       NCAA March Madness


I'm not sure if Telemundo exists on TWC.

John

[Gregg Lengling]

Originally posted by veyj
If TWC is using OTA for the 58 and 41 feeds, they must be using analog 41 instead of 1-2 (46-2).  When the bandwidth is reduced, that channel looks terrrible.

Is the following table accurate?

OTA     TWC

58          5      TWC uses analog 58 for the feed
41          7      TWC uses analog 41 for the feed
63          ?       ?
1-1     505      TWC uses 1-1 for the feed
1-2         ?       Digital 41 does not exist at TWC
1-3         ?       Digital 63 does not exist at TWC
1-4         ?       NCAA March Madness
1-5         ?       NCAA March Madness
1-6         ?       NCAA March Madness


I'm not sure if Telemundo exists on TWC.

John

Actually TWC uses 1-2 for OTA analog 41 to put on channel 7 TWC
The same goes for 63, they use 1-3 to feed it to the cable system

[veyj]

Gregg,

Interesting.  So during the Superbowl, compressed 41 looked terrible and 63 was only available OTA analog and not available on TWC.  Of course I was tuned into the Superbowl but still another reason to dislike multicasting.  41 is going to look really bad come march madness but who'll be watching.

What does TWC use for channel 5 (58)?  Do they use the analog or digital source?  What did they do the other day when the digital signal went down?  Did TWC flip to analog 58?  If they use the digital feed, do they edit/crop/stretch/letterbox the HD content?  Obviously they use 1-1 for the HD channel 505.  

John

[Joseph S]

Fiber optics are great.

[mhz40]

Originally posted by Gregg Lengling
Actually TWC uses 1-2 for OTA analog 41 to put on channel 7 TWC
The same goes for 63, they use 1-3 to feed it to the cable system

That's old news.  Now 41 & 63 are picked up from their analog source and placed on 7 & 66 respectively.

[StarvingForHDTV]

Originally posted by summerfun

If they felt the need to shut down some of the multi casting channels to gave more bandwidth to the Super Bowl, does that mean that we do not normally get the best quality HD for other CBS shows? In other words, can they turn up or down the HD quality of the signal being broadcast by allocating more or less bandwidth?

Yes and yes.  I'm glad Gregg stepped in here too.

Starving