HD TV Charges

Rosa

DTVUSA Member
#1
This may have been addressed before, in which case I apologize, but I've wondered why Cable companies are able to charge more for HD TV when its broadcast is free? In other words, I have and HD TV and if I get an HD Converter box I can get HD reception for free...then why is it that the cable companies can charge for this???

Thanks,
Rosa
 

rabbit73

DTVUSA Member
#2
Do you have cable? Is it just basic cable or more?

Most cable companies provide many more HD channels than you can receive over the air.

Cable companies usually do not encrypt the HD channels that are able be to received OTA, even for basic cable, and these are called clear QAM channels. Lately, some cable companies are going all encrypted so that it is necessary for all customes to have a cable company box for HD.

A tuner like the Centronics ZAT502 HD will receive OTA HD channels and clear QAM digital cable channels.

Many OTA viewers say that the HD quality of OTA signals is better than cable HD, which is because cable companies compress their signals (resulting in reduced quality) to squeeze more into their system.

You can do a search for Comcast qam256 channels here:
hdhomerun/channels - Silicondust
On the page that comes up enter USA and 94044 then click on search. The page that comes up will list 8vsb OTA antenna channels. In the upper left corner change the provider to Comcast and up will come cable 256qam channels. Warning: this list is not kept up to date very well. Talk to your neighbors to find out what clear QAM channels they get, if any.

You can talk to other Comcast customers in your area here:
San Francisco, CA - Comcast - Page 430 - AVS Forum

And here:
http://www.dtvusaforum.com/comcast/
 
Last edited:

bicker

DTVUSA Member
#3
This may have been addressed before, in which case I apologize, but I've wondered why Cable companies are able to charge more for HD TV when its broadcast is free? In other words, I have and HD TV and if I get an HD Converter box I can get HD reception for free...then why is it that the cable companies can charge for this???
Rabbit filled in a lot of the info. As he pointed out, the HD signals for your local, over-the-air broadcast channels can typically be tuned in with your own equipment, if it has a QAM tuner (not all HD converter boxes do), because they are broadcast unencrypted. To address your specific question, it is a violation of FCC regulations for a cable company to encrypt local over-the-air broadcast channels that are broadcast in high definition resolution, even if they provide an unencrypted channel for that local over-the-air broadcast channel downconverted to standard definition resolution. While they are allowed to apply digital compression to fit the high definition signal into a smaller amount of bandwidth, they cannot downconvert it from high definition to standard definition and consider that downconverted signal to be the one that satisfies the regulations.

However, they are not required to provide you the equipment you need to access the unencrypted QAM signal that complies with this regulation -- you have to provide that equipment yourself, and support yourself in connecting it to the service and utilizing it. If you choose to rely on the cable company equipment for this, then they can charge you whatever they wish to enable whatever features of that equipment you want enabled, including the ability to use it for high definition channels. This is the case only because the service mandated by the regulations is available to you without relying on their equipment.
 

bicker

DTVUSA Member
#4
Many OTA viewers say that the HD quality of OTA signals is better than cable HD, which is because cable companies compress their signals (resulting in reduced quality) to squeeze more into their system.
This is generally a myth.

With HD channels delivered via QAM, there are two different scenarios: The general case is where a cable company puts two high definition over-the-air broadcast channels on the same QAM channel. In that case, there is almost always no material degradation, whatsoever. This is because each over-the-air broadcast channel carries 19.28 Mbp/s, while a single QAM channel carries 38.47 Mbp/s. Unless both over-the-air broadcast channels use their entire capacity for broadcasting a single high definition signal (which is very rare - typically at least one of the two is using some of its capacity for a sub-channel), a single QAM channel has no problem carrying the entirety of the data for the two over-the-air broadcast high definition channels. The reason why QAM is so much more efficient than ATSC is because ATSC is intended for over-the-air broadcast and broadcasting through the air encounters substantially greater interference than broadcasting over a wire would encounter, and therefore ATSC includes a lot of error correction -- almost half of the signal is error correction.

The second scenario is where the cable company puts three HD channels on a single QAM. However, I know of no cases where a major cable company puts three (specifically) over-the-air broadcast channels on one QAM channel. That treatment is used typically only for cable networks, not OTA.

I have my television set up so I can watch OTA via antenna or through cable, with the flick of a switch. I've never seen any difference whatsoever, except that the OTA signal is sometimes interrupted by electrical storms in the area, while the cable signal is unaffected by weather.
 

bicker

DTVUSA Member
#6
Thanks for the update... I like to have the specifics available... which cable company and region?

The OTA degradation I encounter due to electrical storms does not rise to the level that would justify waiving of the OTARD-compliant restrictions imposed by my HOA.
 

n2rj

Moderator
Staff member
#7
My cable co (service electric) used to also put SD cable channels along with HD locals. I am not sure how much it degraded the quality (if it all) because I only really recently put up an antenna to compare and by that time all local HD channels were 2 per QAM with nothing else on them except for WNET and WXTV which have some SD channels in the mux but are not bit starved. But they are also 870MHz and are in the process of analog reclamation, with 5 channels gone last month.

As for the HD fee, they charge $5 for HD beyond locals in addition to equipment costs (in which case I pay $0 because I own my cablecards). I think this is reasonable.
 
Last edited:

bicker

DTVUSA Member
#8
I did a little checking and while putting more than 2 HD channels on a single QAM is not common, it isn't rare. Silicon Dust keeps a database where you can check this.

Note again, though, the point: 2 HD channels on a single QAM means no compression. Only 2 HD channels plus 1 or more SD channels would means that the OTA signal needs to be significantly compressed.
 

n2rj

Moderator
Staff member
#9
Note again, though, the point: 2 HD channels on a single QAM means no compression. Only 2 HD channels plus 1 or more SD channels would means that the OTA signal needs to be significantly compressed.
Wrong. 2 per QAM definitely does not mean no compression. No compression would be much more than a 38.8Mbps QAM. All HD signals are compressed. 2 HD per QAM only means that they allow enough room for the full bitrate from an ATSC channel. But the signal is still compressed.

As for 2 HD plus 1 SD, or even 3 HD per QAM that doesn't mean that the cable company recompresses it. Some OTA HD signals are already compressed down to 12 or even 10Mbps. Some are down to 14Mbps max. ABC/Live Well HD is a fine example of this as WABC7 has the main ABC channel with a max bitrate of 12.5Mbps.
 
Last edited:

bicker

DTVUSA Member
#10
Wrong. 2 per QAM definitely does not mean no compression.
Sorry, I wasn't precise: I meant "no additional compression" over what the OTA broadcaster themselves apply. I think your clarification could confuse some people though... we need to make it clear that it was the broadcaster who applied the compression that you're talking about, and that it is the same compression evident in the signal received by antenna.

As for 2 HD plus 1 SD, or even 3 HD per QAM that doesn't mean that the cable company recompresses it. Some OTA HD signals are already compressed down to 12 or even 10Mbps. Some are down to 14Mbps max. ABC/Live Well HD is a fine example of this as WABC7 has the main ABC channel with a max bitrate of 12.5Mbps.
Great point. And it makes sense.... if one QAM could carry two ATSC HD channels using the full 6 MHz, then surely if you have two OTA channels both carrying one HD signal and one SD signal (pretty common), then that means that all four of those signals can easily ride on one QAM, no question, without any additional compression.
 

bicker

DTVUSA Member
#11
Of course, what n2rj points out there, in the second half of his message, kind-of invalidates the investigation I did earlier... because now even though there are some cases where a QAM carries more than just 2 HD signals that doesn't necessarily mean that that will in any way adversely impact picture or audio quality, as compared to reception via antenna.
 
Top