Trying to understand HD
Errol_Summerlin

So, I recently purchased a brand spanking new Samsung 50 inch HD TV to replace my 19in SD TV. The model number, in case it is relevant for ensuring it comes with the correct equipment is PN50B560. I also have an SD set top box. 

My FIOS plan (the most basic one) includes 12 HD channels. These are mostly channels that you could get in HD over-the-air (OTA) without purchasing cable TV. So I have several questions. I "think" I know the answers to all of them, but I want to make sure.

1. If I did not have FIOS and I plug my TV directly into the wall via the coax cable, would I get the basic OTA channels (PBS, ABC, CBS, NBC, etc.) in HD? I believe the answer is yes.

2. If I simply plug my set top box into my new tv instead of my old one (using any of the connections available on the SD set top box...the TV can accommodate a variety). Will channels 510, 511, 512, etc.  (the same basic OTA channels as above according my available channel listings) be in HD? I believe the answer is no.

3. If the answer to (1) is yes, and the answer to (2) is no as I believe, please explain why the SD box does not just let the HD channels pass through. The SD box must be then actually purposefully reducing the image quality to make people buy the HD box when it could just let the signal pass through to the TV on the other end which will then display it in HD if the TV has that capability and in SD if it doesn't. My question then is How is this not a willful attempt to squeeze more money out of your customers to get HD channels that they could already get OTA if they DIDNT have cable? Again, this is just how it seems (based on my reading) that this system works. If I am right about how it works, then this is shameful way to make 5 more bucks a month and I am determined to find a way around it. If I am misunderstanding something, I apologize for seeming accusatory, but everything I have read so far indicates that the above is how it works. In fact, if this IS how it works, I will seriously consider discontinuing my service with verizon so I can watch HD channels.

4. I will NOT purchase an HD set top box or a channel package with more HD channels without first having the opportunity to view HD programming on my tv and see if it is worth it. So, I thought about it a little and I have an idea, but since my TV is not here yet, I can't try it out. My questions is: will the following work? I will take the co-ax cable from the wall into a splitter. Send one half of the split signal directly into the co-ax input on the back of my TV. The other half of the split signal goes into the set top box. I then connect the set top box to the TV via something other than a co-ax (since the TV only has one Co-Ax input). Then, if I want to watch cable channels, I use whatever I hooked the set top box up to, and when i want to watch HD OTA programming, I switch to the co-ax input on my TV. So, will it work?

I thank you for your response,

EJ 

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Re: Trying to understand HD
StuffOfInterest
Enthusiast - Level 3

You missed one key fact regarding the coax output from the SD box.  It is not a pass-through, it is a transmitter.  That coax output is going to send analog NTSC out on either channels 3 or 4 (I believe) which is intended for REALLY old TVs that don't have an auxilary input.  I believe the coax output on the HD box is the same as well and will only send SD channels to channels 3 or 4 on your TV.

To get the direct HDTV channels on your TV you'll need to get a coax splitter and a couple of short coax cables at your local home improvement store.  Run coax from the wall to the splitter and then one coax from the splitter to the TV and another from the splitter to the cable box.  This will let you get the encrypted SD channels via the cable box and the unencrypted SD & HD channels directly on the TV.

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Re: Trying to understand HD
StuffOfInterest
Enthusiast - Level 3

OK, I'll take a stab at this.

First off, Verizon broadcasts all channels using the digital QAM format.  SD analog channels were sent via NTSC, but Verizon stopped sending them a couple of years ago as you can fit several QAM streams in the space taken up by one NTSC stream.  Older, non HD analog TVs, can only decode NTSC so an analog TV won't see anything if directly connected to the cable coming out of the wall.

Next, there are two ways QAM can be sent, clear and encrypted.  Only the local channels (those in 1-49 for SD and 1-50 in HD) are sent in the clear.  The rest are encrypted.  HDTVs can only directly decode the clear channels so if you hook the cable straight into the TV and do a scan you should find zero analog channels and both low definition and high definition versions of the local channels.

There is one issue to be aware of here.  The Verizon channel numbers (1-2000ish)  are not the channel numbers you will see on your TV for QAM channels.  Part of the QAM information sent is channel mapping.  In my case, NBC Channel 4 is channel 504 on Verizon but comes through as channel "4.1" on the TV.  If you have an on-screen TV guide in your TV it should tell you what channels are what, but if it doesn't you may have to hunt around a bit to figure out what numbers go to which channels.

Now, on to set top boxes.

A digital adapter or SD set top box can only decode the SD channels.  These channels are (I believe) sent in 480i (480 pixels across, interlaced).  To actually convert a 720p or 1080i HD down to 480i for output to an analog device would require a lot more horse-power (CPU speed & memory) than the set top box is likely to have.  That's why a SD box will only output SD channels, no ability in hardware/software to convert between signal formats.

An HD box or HD DVR box has the digital outputs to go to an HD TV as well as analog output that can go to an older, analog only TV.  The thing is, if you have a HD box and hook an SD TV up to it you still won't be able to watch the HD channels.  Again, the box won't convert between formats so it won't be able to send it out to the analog TV.  Still likely a horse-power issue.

As for your overall issue, if you have a 50" HDTV and you hook your cable up to it you should be able to see some HD channels.  Try watching prime-time on the major networks and you'll see just how crisp HD can be.  Too bad you are a couple days late for the Olympics.  NBCs Olympic coverage was stunning in HD.

Hopefully this helps.  If you haven't had HD before I think you'll be blown away when you see it.  I know I was.

Re: Trying to understand HD
Errol_Summerlin
My responses are interlaced in between paragraphs

@StuffOfInterest wrote:

OK, I'll take a stab at this.

First off, Verizon broadcasts all channels using the digital QAM format.  SD analog channels were sent via NTSC, but Verizon stopped sending them a couple of years ago as you can fit several QAM streams in the space taken up by one NTSC stream.  Older, non HD analog TVs, can only decode NTSC so an analog TV won't see anything if directly connected to the cable coming out of the wall.

--->Though I didn't know all the acronyms, this is as I understand it. My old 19 inch tv is analog and I had to get a digitial to

--->analog converter in order to see local channels with it. However, my new TV should be able to be plugged directly into

---> the wall because it is digital ready....I think.

Next, there are two ways QAM can be sent, clear and encrypted.  Only the local channels (those in 1-49 for SD and 1-50 in HD) are sent in the clear.  The rest are encrypted.  HDTVs can only directly decode the clear channels so if you hook the cable straight into the TV and do a scan you should find zero analog channels and both low definition and high definition versions of the local channels.

--->So, my HDTV should get local channels in HD if I hook it up directly to the wall

There is one issue to be aware of here.  The Verizon channel numbers (1-2000ish)  are not the channel numbers you will see on your TV for QAM channels.  Part of the QAM information sent is channel mapping.  In my case, NBC Channel 4 is channel 504 on Verizon but comes through as channel "4.1" on the TV.  If you have an on-screen TV guide in your TV it should tell you what channels are what, but if it doesn't you may have to hunt around a bit to figure out what numbers go to which channels.

--->I remember that from when I had my analog TV hooked directly into the wall before I got cable here. 

Now, on to set top boxes.

A digital adapter or SD set top box can only decode the SD channels.  These channels are (I believe) sent in 480i (480 pixels across, interlaced).  To actually convert a 720p or 1080i HD down to 480i for output to an analog device would require a lot more horse-power (CPU speed & memory) than the set top box is likely to have.  That's why a SD box will only output SD channels, no ability in hardware/software to convert between signal formats.

--->but for channels transmitted in the clear the set top box has no work to do. It needs literally 0 horsepower...all it needs to --->do is be a co-ax cable.The signal is already HD, and it does not

--->need to be decoded. It is, as you said earlier, transmitted in the clear. There is, as far as I can tell, no need to convert

--->between signal formats. Essentially, the SD box is BLOCKING free HD channels that are transmitted in the clear and

--->need no processing. I am not an electrical engineer, but it seems that if the co-ax coming out of the wall can carry an

--->HD signal, then the co-ax coming out the back of the set top box and going to the tv can carry that same signal. But

--->verizon chooses to block those channels rather than just putting simple switch in the software that tells the box not to

--->touch an HD signal. I definitely don't expect an SD box to decode and re-transmit channels that are not in the clear (this --->appears to be what you were talking about above)

 An HD box or HD DVR box has the digital outputs to go to an HD TV as well as analog output that can go to an older, analog only TV.  The thing is, if you have a HD box and hook an SD TV up to it you still won't be able to watch the HD channels.  Again, the box won't convert between formats so it won't be able to send it out to the analog TV.  Still likely a horse-power issue.

As for your overall issue, if you have a 50" HDTV and you hook your cable up to it you should be able to see some HD channels.  Try watching prime-time on the major networks and you'll see just how crisp HD can be.  Too bad you are a couple days late for the Olympics.  NBCs Olympic coverage was stunning in HD.

--->the above is somewhat ambigous...you said "hook your cable up to it"...as in, through the SD set-top-box? through an

--->HD set top box, or directly from the wall? "cable" can refer to a physical co-ax cable or the cable box. I read accounts of

---->several people on-line who claim that hooking up the SD box to their HD TV results in ABC HD, NBC HD, and other in ----->the clear HD channels being blocked

Hopefully this helps.  If you haven't had HD before I think you'll be blown away when you see it.  I know I was.

---->Answered some of my questions. Educated me a little bit too about the jargon. Thanks for the response.

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Re: Trying to understand HD
StuffOfInterest
Enthusiast - Level 3

You missed one key fact regarding the coax output from the SD box.  It is not a pass-through, it is a transmitter.  That coax output is going to send analog NTSC out on either channels 3 or 4 (I believe) which is intended for REALLY old TVs that don't have an auxilary input.  I believe the coax output on the HD box is the same as well and will only send SD channels to channels 3 or 4 on your TV.

To get the direct HDTV channels on your TV you'll need to get a coax splitter and a couple of short coax cables at your local home improvement store.  Run coax from the wall to the splitter and then one coax from the splitter to the TV and another from the splitter to the cable box.  This will let you get the encrypted SD channels via the cable box and the unencrypted SD & HD channels directly on the TV.

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Re: Trying to understand HD
Errol_Summerlin

that last paragraph is what I really needed to know. I already have the splitters and co-ax cables...I hoard miscellaneous electronics cables, splitters, and converters for reasons involving a bit of OCD and being extremely poor until 6 months ago and never throwing away anything that could potentially be worth more than 10 cents.

As for the first paragraph, I want to make sure I understand, so I will try and restate what you said in my own words.

If the incoming signal is digital (QAM?) SD(either encrypted or in the clear), the SD set top box takes this QAM signal in, decodes if necessary, and re-transmits it as NTSC analog, RCA(component), S-Video, D-SuB(PC/VGA), or whatever other outputs it has on the back.

If the incoming signal from the wall is an encrypted digital(QAM?) HD signal, then the set top box simply doesnt have the hardware or software to decrypt it.

If the incoming signal from the wall is an unencrypted digital(QAM?) HD signal, then the set-top box can not convert it to a different output, but it has no pass-through to let the signal through, so it just throws the signal away.

If the above is correct then I have successfully absorbed the what. Thank you. I doubt you will be able to answer the why though unless you work for verizon or build these things for a living.

The WHY:

So, that much I get (I think). However, you said "it is not a pass-through, it is a transmitter". Well, the logical next question is: For HD channels broadcast in the clear, why not? The cost of just leaving a signal alone is probably about the same as suppressing it. The Co-Ax cable that carried it in is no different from the one that would be carrying it out. It would be far more convenient for Verizon customers to NOT need to do what you described in the second paragraph (which was essentially what I described in question 4 of my OP) to get the free HD channels on their HD TV. The cost of producing an SD box that lets in the clear HD signal pass-through seems basically the same as an SD box that kills in the clear HD signals. Thus, it costs the company almost nothing, and gives customers with HD TVs a few basic HD channels even with the SD box. So why hasn't verizon done this?

With no other explanation for the why, it seems to me that they believe that the extra $5 bucks they can squeeze out of people by forcing the not-so-technically-savvy(those who can't follow your second paragraph) to get more expensive HD boxes in order to get FREE HD channels is worth more than the extra market share they would collect if they just made the SD boxes pass-through the unencrypted HD signal. Or perhaps they have realized that the fix is so easy that, as soon as they did it, every other company would do it. They wouldn't gain any market share, and all of them would make less money off of the technically disinclined thus making their refusal to do this a form of collusion.

I guess I shouldn't care so much since the fix in your second paragraph will give me what I want..the opportunity to try HD channels and compare them to non-HD before I upgrade to an HD box or get more HD channels. But it still bothers me that I had to spend a good number of hours trying to figure out how to get around an artificial restriction that shouldn't be there in the first place.

Thanks again,

EJ

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Re: Trying to understand HD
StuffOfInterest
Enthusiast - Level 3

You are getting close now.

It is not just HD channels that are encrypted, all channels (SD & HD) are encrypted if they are outside that 1-49 and 501-549 range.  The local channels are kept unencrypted by FCC rules.  For everything else, cable operators use the set top box to determine what channels you have subscribed to and only decrypt those channels.  One big benefit for the providers is that it keeps pirates from tapping into their neighbors cable and getting all the channels they do.  Unless you have a registered box you won't see anything but those local channels.

Now, for your why question.  The extra hardware likely is part of the equation.  Back in the dark ages before HD, I had a set top box which did do a pass through the way you describe.  This was actually a mechanical relay which I could hear click every time the box was turned on or off.  I'm not sure why the set top box manufacturers started to leave it out, but they did.  This isn't a Verizon issue but something that Motorola and Scientific Atlanta did.

Good luck with your test drive of the HD channels.  I'm sure you'll be pleased, amazed, and asking for more channels.

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Re: Trying to understand HD
Rebalol
Contributor - Level 1

An HD box or HD DVR box has the digital outputs to go to an HD TV as well as analog output that can go to an older, analog only TV.  The thing is, if you have a HD box and hook an SD TV up to it you still won't be able to watch the HD channels.  Again, the box won't convert between formats so it won't be able to send it out to the analog TV.  Still likely a horse-power issue.


One correction. The above is not true.  I have an HD box on my analog tv and can watch hd channels. I had to get it becasue of the multi-room capability; if I record it in HD on the main tv and want to watch it in another room, non HD, it didn't work until I switched the box from SD to HD.

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Re: Trying to understand HD
StuffOfInterest
Enthusiast - Level 3

Thanks for the correction.  I didn't think it would downconvert.  Don't mind being proven wrong on this one.

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Re: Trying to understand HAD
jmw1950
Specialist - Level 2

You certainly CAN watch HD channels on an SD TV if you have an HD STB. The HD STB's output S-VHS, Composite Video, and  component /HDMI simultaneously.  Component output can be set to  480i (and there are a few SD TV's that support  480i and/or 480p input). So the HD STB's will quite happily output NTSC as either composite video or S-VHS to SD TV without component video inputs.

I have a QIP6416, the S-VHS output runs to a VCR (and it works), and I use 480i for the TV. While 480i isn't true HD, it is in fact substantially better than the old over the air NTSC.  NTSC/composite video  is limited to about 330 line resolution (exactly how good it was depends upon how good the comb filter in your TV is, it could be as bad as 260 lines). S-VHS can support about 400 line resolution, and 480i or 480p is 480 line resolution.

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Re: Trying to understand HD
JD4x4
Enthusiast - Level 2

This is a great thread .. Thanks to all for the info. It's also one of the few open treads about ClearQAM where I can ask this question! :

Simply put, so any channel listed as "Local Plus" (seem to be in the 400 series in my area but are available OTA locally) are NOT ClearQAM?  Meaning they're encrypted so I can't get them without an SD or HD STB even though I have QAM tv's or other QAM tuner devices.. yes?

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