: Question on Bandwidth Constraints
2010-06-12, 10:01 PM
I am very interested in IPTV . . . I just started reading about it over the past week or so and it seems very intriguing. Anyway, here is my question . . . does anyone know how many HD channels can be viewed at any given time? Say for example, my father is watching a HD channel in the basement, I am watching another HD program on the main floor and recording another HD channel all at the same time. From what I can tell there seems to be a constraint with bandwidth which concerns me.
Thanks in advance!
2010-06-13, 02:05 AM
I just had Fibe 25 installed from Bell. Fibe 25 is VDSL2 which is the backbone for Bell’s soon to be introduced IPTV service.
As you know Fibe 25 delivers 25Mbit download internet speeds, but when the tech was here installing the service he did a line test and I had 48 Mbit speed over my line… this meant that there was another 23 Mbit available for the IPTV service if I so should choose to have it too. 23 Mbit will give you 2 HDTV channels and one or 2 SDTV channels all at the same time. This is what the Bell IPTV system is designed to support.
Oh and don't forget this is over a single pair of phone wires. Most homes have 2 or more pairs coming into the house so you 'could' have over 2 pairs of wires 4 HD programs, and 4 SD programs and an Internet speed of 50 Mbit all at the same time (theoretically speaking).
2010-06-13, 10:14 AM
Here's how it works:
SD Stream takes approx 2-3Mb
HD Stream takes approx 5-7MB
You're allocated approximately 25Mb down for if you have one receiver, and what they used to do (and I think they still do), is add another 5Mb to your total download speed for each additional receiver you request (up to a total of 3 receivers per houshold). Now, I think each console is able to capture up to 3 streams, and I think the numbers are 2HD / 1SD, so you could record 2 HD streams, and watch an SD stream, record 1HD, 1 SD, and watch 1 HD. Maybe someone else can chime in on this, but I havn't really tested it. Maybe it's time I do this test myself.
VDSL2 in it's current state is able to get up to about 35-40Mb down, but they typically only allocate 25Mb plus about 5Mb for additional consoles.
One of the other guys said they could stream additional content over a different pair, and they would not do it this way. This would be way too complicated to do. It would require 2 VSDL2 modems and 2 sparate accounts most likely.
2010-06-15, 08:09 PM
Using the Network Monitor on Windows 7, my HDHomerun tuner uses 18 - 19 Mbps when streaming a 1080i signal from my antenna (2 channels at once are close to 40 Mbps).
I don't know what the differences in bandwidth requirement are between OTA and IPTV, but I would imagine even removing the error correction from the OTA stream a 10+ Mbps difference would result in much lower quality video.
During the Stanley Cup finals, flipping from NBC (about 11 Mbps because of subchannels) to CBC (18 - 19 Mbps) there was a noticeable PQ difference.
2010-06-15, 10:24 PM
You need to factor in compression. Bell's IPTV (now called Fibe TV) uses MPEG4 compression, so they can get an HD stream sent through a pipe using approximately 5-7Mb, maybe 8 at the most. I think the most they allow you to view at a time is 3 HD streams now, so your're topping off at about 24Mb - probably closer to 21.
Now that it's realease, I'm not sure if iPTV eats into your allocated bandwidth, becasue technically, with iPTV, they CAN allocate up to around 40Mb down fairly easily, so what they might do is you sign up for one of their FIBE services, then they allocate additional bandwidth only to be used by the TV stream. This is all speculation here, but it's a possibility. I kind of look at it this way because they say you need to sign up for 'a FIBE Internet Package', it sounds as if you could sign up for the FIBE6, which on it's own would not give you enough bandwidth to support TV well, so that is why I am guessing they would allocate additional bandwidth for your iPTV portion.
2010-06-15, 10:48 PM
So if I I have Fibe6, and FibeTV, television will be allocated with 24 mbps bandwidth and the internet will take only 6 of that? Or I will be allocated 30 mbps and internet will still only be able to take 6 mbps? Or both are combined and even though I have fibe6 I can stilll download at 24 mbps when not watching tv?
So the price listed on the new sticky thread is for only TV and if you add internet it costs just as much as it regularly does even though TV is already done through internet..?
What website is all that listed on?
2010-06-16, 09:35 AM
Don't think of TV as gonig through 'internet'. TV goes through more so Bell's INTRANET, meaning it doesn't really go to the public internet at all.
The modem you get allows for 2 logins. One is for your 'internet stream', and the other one is for 'iptv stream'. The stream for iptv can't actually hit the internet at all. It can only route to servers on Bell's network. It's what is called VLANNING. The TV stream is only allowed to get to Bell's servers, and the internet stream can go...while, to the internet.
It's kind of confusing, but with 2 logins, they can provision the modem so that each login is able get different speeds. How else would they restrict someone from only getting 6Mb when a lot of lines would support 25Mb (FIBE25). The PPPOE login lets them set the parameters for your connection. The only other possibility is they do this at the port level, so they would have to configure each port. I'm sure someone with more knowledge would be able to answer how they provision the speeds,
HD Stream takes approx 5-7MB
I know its MPEG-4 encoding but with that kind of compression, it barely qualifies as HD. FYI, Blu-ray is 18 to 40 Mbps.
By comparison, Bell TV is 14.6 Mbps at MPEG-2. Even with a 50% reduction in bitrates using MPEG4 (which is a generous estimate) it suggests that Fibe TV won't even deliver the type of quality achieved by Bell TV.
2010-06-18, 11:10 PM
It would be useful if someone that has the new Fibe TV installed could provide some info. What are the number of HD and SD streams and what is the Bandwidth Cap on the PVR.
Assuming Bell's menus are the same as mine on MTS: on the PVR, press Menu, Settings, General, System Information, System Resources.
2010-06-18, 11:21 PM
According to the website you can record 4 shows at a time. This could two standard and two hi definition. BES picture appears less compressed on HD than ExpressView.
2010-06-19, 03:17 PM
I think it's because it's a better compression technique they use. I'm pretty sure BES uses MPEG4, whereas ExpressVu uses MPEG2?
MPEG4 from what I've heard does a better job at compressing the signal, but still looking good on the TV. I would guess this might be why the bandwidth an HD stream uses on BES might be lower than what some are used to with other services available in Canda. I'm pretty sure Rogers also uses MPEG2. I'm not sure about Shaw Direct - I think they might be the same..
BES could still very well be more compressed than ExpressVu, but if they use better compression, then you may think it looks better. I heard that blacks on the screen are much better with MPEG4 compared to MPEG2 (and I do notice this myself). You tend to see lots of pixelation on black's with MPEG2, but I don't see it so much with MPEG4.
Check on Google the difference between MPEG2 and MPEG4. There's lots of info about the two, and from what I read, it is better overall.