VOOM HD? Really dont think so

[Sean Mota]

Ever heard of variable bitrates...?

 

[vurbano]

Thats basically good info except for the fact that Voom uses variable bitrate encoders and assigns bandwidth instantaneously as demanded. Good numbers but the analysis is DEAD WRONG. The bandwidth is variable, not fixed. Therefore Voom makes use of all of it and doesnt have 40%- 60% of each channels bandwidth filled with null packets most of the time.

here is a post from Dan Collins that explains Voom's bit rates:

Voom has 13 transponders in operation (11 licenses of their own, plus 2 unassigned that they use temporarily). They use a higher symbol rate than Dish or DirecTV, and they use 8PSK modulation. As a result they get a total of 66 megabits per second per transponder, 11 Mbps of which is used for error correction code. So, each transponder can deliver 55 megabits per second of data.

They carry 37 HD channels. If they were to deliver these channels all in ATSC standard 1080i, they would be able to fit 3 per transponder. That's 12 and a third transponders right there. They also deliver almost 90 SD channels. Even at 2 Mbps each (well BELOW the average for Dish and DirecTV) that would require 3 and a third transponders. Therefore, they MUST be compressing the HD below the ATSC standard.

If, as is claimed, Voom's SD content looks better than Dish and DirecTV's, they can not be compressing the SD channels below an average of 3 Mbps. That means that those 90 channels will require 5 full transponders.

That leaves 8 transponders for 37 HD channels. The bottom line is that the HD channels can't be getting more than 12 Mbits/second, or just about what DirecTV is giving their HD channels (and which many people complain is not enough). Of course, since much of the HD content is not a live feed (their proprietary content) they can spend a lot of time tweaking the compression to make these channels smaller and minimize the appearance of compression artifacts. But 15 of those channels ARE live feeds (HBO HD, ESPN HD, etc.) and so will require an average of 15Mbps to look decent. So that's 225 Mbps off the top, leaving 215Mbps for the other 22 channels, or about 9.7 Mbps second (slightly more than the average DVD).

Do the math yourself....the total bandwidth available is 715 Mbits/second. Figure out how to allocate that space to 37 HD and 90 SD channels and end up giving channels more bandwidth than does Dish or DirecTV. What you'll find is that they MUST be compressing some channels pretty severely - it's just a matter of which ones.

For reference, here is the bandwidth used by Dish Network and DirecTV for core (not locals), counting only the CONUS capacity:

Dish Network: 1,320 Mbits per second (1.8 times as much as Voom)
DirecTV: 1,224 Mbits per second (1.7 times as much as Voom)


http://www.dbsforums.com/vbulletin/...1107#post331107

 

[gross67]

Any luck getting your PQ straightened out?

 

[joemama]

I think the Voom transponders have 50 Mbps bandwidth each and the others like D* have 20-30 Mbps capacity. SO I believe you are comparing apples to oranges. Someone help Ive forgot the numbers.

Do the math. MSymbols/sec * FEC * Bits/Symbol = bitrate

According to the numbers on Lyngsat.com:

A V* 8PSK transponder = 22Msps * 5/6 * 3bits/sym = 55Mb/sec

A E* 8PSK transponder = 21.5Msps * 2/3 * 3bits/sym = 43Mb/sec

A E* QPSK transponder = 20Msps * 5/6 * 2bits/sym = 33.3Mb/s

 

[jorsan]

Thanks to all for their responses. As I mentioned before, I have the knowledge to deal with configurations, menus etc. and understand the difference between all of this so Im sure that this is not the reason. Its just that I remember much better picture quality before but almost all of you are telling me that this is not your idea so maybe its just me, dont know . . . .

 

[FreddyvsJasonvsAsh]

I was at Cox Cable yesterday and the lady told me that VOOM isn't true HD and don't be fooled by what they are telling everyone. Now I know I'm not the only one this has been said to. I thought I read on here that Dish and Direct TV are telling people the same thing. Is this true? I wouldn't bother listening if it was only one person saying this but almost all the other companies are. What are your thoughts on this?

 

[BFG]

Yes that's the same line charlie used on some of his chats, so maybe they do know something about the workings of voom.

 

[jorsan]

Yesterday the people of DISH NETWORK call me asking why I was leaving and in a part of the conversation, they told me the same . . . .

 

[andrzej]

What do you expect from V* competitors? Acknowledging that Voom's HD offer is better than theirs?

 

[voomster2]

ALL of VOOM's competitors need to say is "We have a working HD-DVR available today and VOOM doesn't. The choice is yours."

 

[ram1220]

Well DVD's sure look better than anything I've seen on Cinema 10 lately. Maybe there's some truth in it.

 

[andrzej]

ALL of VOOM's competitors need to say is "We have a working HD-DVR available today and VOOM doesn't. The choice is yours."

Sure, the choice is mine. I've never used Tivo (or equivalent) and I've never had any desire to have one.

 

[voomster2]

Sure, the choice is mine. I've never used Tivo (or equivalent) and I've never had any desire to have one.

You are in the minority on this one.
VOOM needs to appeal to the majority.

 

[jagouar]

ALL of VOOM's competitors need to say is "We have a working HD-DVR available today and VOOM doesn't. The choice is yours."

The only problem with that statement is every body but the cable co's charges an insane amount to buy. They really need to get a 10/month lease option before they can actually market it to the masses.