BTV bitrates discussion (split from PQ thread).

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Some of the comments about differences in channels do not make sense from a satellite perpspective.
Each transponder can deliver 43 mbps (megabits per second).
Now one OTA channel can deliver a maximum of 19 mbps but most people say that is overkill and not needed. The minimum that most people would accept as HD is 10 mbps, although many argue that 12 mbps is the minimum, but it is somewhere around there.
During the Olympics, CTV East was on a transponder with 3 channels. If Bell divided them up equally it would be 14 mbps per channel.
TSN is on a transponder with 4 channels so it would be only 11 mbps per channel. Whether Bell would "shape" this to deliver more mbps to a "more important" channel and less mbps to a "less important" channel is unknown.
The East US Networks are:
ABC 4 channels per transponder
NBC 3 channels per transponder
Fox 4 channels per transponder
CBS 3 channels per transponder
Everything else being equal, if your picture quality evaluation between Bell channels somewhat correlates to these numbers, it would make sense. If not, something else is clouding the issue.
As for picture quality between providers, the Bell US Nets are from Boston while Rogers gets them from Buffalo, so that could be an important factor.

I will be doing a comparison, when I get some time, between OTA Global Toronto (4 channels per transponder on Bell) and CITY (a whopping 6 channels per transponder) just to see how different they may be compared to CTV.

Edit - Corrections issued in post 13.
 
I was of the understanding that each transponder has about 30 mbps, not 43 and that almost all transponders have 3 HD channels on them, although it would be possible to mix in some SD.
 
A 27 MHz Ku/DBS transponder has a maximum data rate:
in QPSK ~ 29 Mb/sec
in 8PSK ~ 40 Mb/sec
in DVB-S2 ~ 52 Mb/sec

All of it is not usable - normally 5 to 7% is used for operational necessities
 
The formula for the Bell transponders which use 8PSK modulation is:
3 bitspersymbol X 21.5 megasymbolspersec X 2/3 FEC = 43 mbps.

Any HD transponder has only HD channels and no SD channels.

The lowest number of HD channels per transponder by Bell is 2 and the highest number is 6. The most common number is 4.
 
I don't know where you get these numbers of channels per transponder, but based on the people here who have HTPCs, most of the HD channels were around 10 mbps average (the maximum SD DVD bitrate, just for comparison and down as much as 40% from the ATSC max). Also, I believe the channel number can be confirmed by looking at the information on the BTV STB screens. At 6 channels, based on your 43 mbps, you'd only have 7 mbps, very low...

I'll move this discussion to a separate bitrate thread.

Is BTV on 8PSK?
 
Although more than 4 services are listed as being available on some transponders, this does not occur at the same time. Some transponders have seasonal and part time channels.

For instance, the HD PPV channel on a transponder is not used when that transponder is providing an NFL Sunday Ticket feed. Some transponders list MLB Extra Innings and Centre Ice channels, which are not used at the same time.

Bell does not operate more than 4 HD services on a transponder at any given time.
 
LyngSat has a good site,they have a page that shows all the channels and their transponders found on both Bell satellites.

Transponder numbers are in the first row.Seems like a maximum of 3 full time HD channels and some PPV on one transponder,or 4 full time channels on a transponder.

http://www.lyngsat.com/packages/bell2.html for 82

http://www.lyngsat.com/packages/bell1.html for 91
 
Transponder 12 has 2 English HD PPVs and 2 French HD PPVs. It's common for Bell to use the same video feed with different soundtracks (English and French). In fact, they are doing this right now with The Hangover and A Perfect Getaway - showing them at the same time in French and English with their respective soundtracks. Therefore, what looks like 4 "full time" channels is actually only 2. In other words, the same video is mapped to 2 different channel numbers but the audio is different.
 
VuMax,you know your stuff.

Would I be right to assume that Nimiq 4(82) is at near capacity.
People expecting a ton of new HD channels might be disappointed.
 
At the moment, transponders 1 & 2 are all SD signals. The rule of thumb is usually about 6 SD channels take up the same space as 1 HD channel. That means they could fit at least 1 HD signal in with the SD signals on each of those transponders and possibly 2 with their "aggressive" compression.

Many transponders have, for instance, 1 Centre Ice feed and 1 MLB Extra Inning feed, etc. If they avoid using these at the same time, the HD additions listed below are possible. As well, many TPs listed below currently only have 3 services on them.

There's room for maybe a couple of HD signals on TP6.
1 more could be added on TPs 8, 9, 10, 11, 13, 17, 18, 20, 24 and 31.
2 more on TPs 15 and 16.
 
Thanks VuMax.

That is very helpful and I won't need to waste my time comparing CITY with OTA. I still plan to check Global (4 channels per transponder) with OTA, because to me, CTV East (3 channels per transponder) has excellent HD quality.
 
Thanks again to VuMax for enlightening me about the French language ppv's.

That makes my first post incorrect.

TSN is on a transponder with 3 channels (my original comment of 4 is incorrect) so it should be every bit as good as CTV East.

The maximum number of "full time" HD channels is only 4 per transponder (my original comment of 6 is incorrect).
 
If you check out the picture quality thread, I have come to the conclusion that the structure of channels per transponder is only a minor factor (as long as they don't go above 4 channels).

Whatever systems Bell is using to lower the bitrate that is content dependent is probably more important, and I'm sure that is proprietary information that they will not share.
 
Also, I believe the channel number can be confirmed by looking at the information on the BTV STB screens.

Is there anyone who knows how to find the information of Mbps on a specific channel by the TV screen? Thanks!

Ben
 
It's not possible with your receiver alone.

There is a "crude" way to check it by recording a program with your pvr and checking to see how many hours and minutes available were reduced after the recording. Use search to find more details if you're interested but this technique is not generally accepted as being very good, especially for programs that are short. If you did it for say 8 hours straight it might be a better indicator.

There are software programs that do this but you need some specialized cards and hook up your pc to the satellite feed.
 
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