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What's needed to receive HDTV from Comcast?

Last response: in Graphics & Displays
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December 16, 2006 12:48:03 AM

I get standard cable TV service through Comcast in the northwest suburbs of Chicago. If I buy an ATI 650 HDTV card for my computer, would I be able to receive HDTV through the same cable through which I now get the regular TV service? I've got an Avermedia TV tuner card in my computer now, and it works well, but I'd like to get a better picture.

On their web site, Comcast says it charges $5 extra per month for HDTV service, and that you also need a set-top box. If you already have an HDTV tuner, either a computer card or an HD ready TV, why do you need a set-top box?

These may seem like simple questions, but I really know nothing about HDTV.
December 16, 2006 2:44:29 AM

Quote:
why do you need a set-top box?
The cable set top box does the decryption of the encoded HDTV content.
If you have a HDTV ready TV with QAM you can get the "free" HDTV channels with just the TV.

The ATI 650 HDTV card is good for OTA (over the air) HDTV only.
With a QAM PCI HDTV Tuner/Decoder Card you can get the unencrypted "free" HDTV (ABC, CBS, NBC, Fox, etc.) off the cable but they cost something like $150

This article will give you some perspective on cable HDTV to PC and DRM issues: When will HDTV over cable come to Media Center?
December 27, 2006 2:39:38 PM

Quote:
Yep you will have to pay for the service and get the set top box. The you can plug that box into your current card to watch it on your PC. Though you will still be watching it in 800x600 resolution and you will be changing channels from the box. If you get an HD tuner card you will be able to receive OTA HD channels. You know the ones that say braud cast in HD. You'll be able to pick up the HD signal of those braud casts.
Sprechen sie deutsch? :wink: ( "braud cast" -> "broadcast" )
I am currently building a new system and am confronted with the conundrum of this thread. I already pay comcast for digital hd cable but I also want to plug the cable into the pc in my room(possibly running mythtv). I don't mind paying for a second box, but I certainly want hd resolutions. Does this have to do with HDCP? the way it limits the output if being sent to a non-HDCP device like a PC? Although my research shows some HDCP nvidia graphics cards so it seems like there should be some way to display hd signal from digital cable on a PC instead of only local OTA channels.
All this DRM crippling is really annoying, I just want to pay money for good content and display it wherever I want to. :x
Related resources
December 27, 2006 3:23:07 PM

Are there any HDTV PCI tuner card with CableCard?

That is the only way to get ALL Cable HDTV channels on your computer.

As there are no capture cards that offer Component-in
you would not get HiDef by using svideo-in on a $30 capture card

A PCI card that supports QAM (TV over cable) and is hi-def do cost
$150+ and you still only get the non-encrypted channels.

PCI cards that supports HD Over Air can be found for $80
December 27, 2006 4:38:08 PM

For Comcast HD content (encrypted) I think the only way to get it to a pc is using the Firewire port on the back of the DVR. instructions can be found here: http://replayguide.sourceforge.net/dct6412/index.html

It links back to an AVS Forum topic on the subject. There are some catches though because the Motorola box will not output protected content on the firewire connection so you may not be able to record some shows.
December 27, 2006 5:06:30 PM

Thanks for the pointer to the firewire solution. Although that was for windows and I use linux it pointed me in the right direction. It turns out mythtv actually already has support for recording from firewire from a cable box this way.
So using the motorola cable box gets us around one level of encryption so we can watch more channels on our PC, but there is apparently yet another level of encryption! As this guy says:
Quote:
The downside is that I can’t record HD channels that have 5C encryption on them, which turns out to be all the non-network HD channels (INHD, Discovery HD, ESPNHD, etc.). I thought it would just be HBO, but no such luck.
and by record - with mythtv - that also means you can't even view them on your PC.

I'll investigate CableCard now.
October 25, 2007 8:52:39 PM

www.okoromedia.com
the only ati cablecard tuner's ive seen are external boxes which sucks. but these guys have internal ones. supposedly dell is going to get them soon too...cox in RI charges 1.99 per month for the cable card (plus installation) and if you dont mind losing ondemand and the guide, they are great.
October 25, 2007 9:06:26 PM

With the cablecard can you pick up the encrypted channels as well. Discovery, ESPN, etc.?
October 25, 2007 11:38:36 PM

thats the whole idea behind it. it decodes the encrypted channels, so yes you will get HBo, stars, espn, etc whatever your cable company has. and you will be able to record whatever you please, until they turn on the dreaded copy protection bit/flag/whatever. until then, happy recording!
October 26, 2007 12:27:27 AM

WR2 said:
Quote:
why do you need a set-top box?
The cable set top box does the decryption of the encoded HDTV content.
If you have a HDTV ready TV with QAM you can get the "free" HDTV channels with just the TV.

The ATI 650 HDTV card is good for OTA (over the air) HDTV only.
With a QAM PCI HDTV Tuner/Decoder Card you can get the unencrypted "free" HDTV (ABC, CBS, NBC, Fox, etc.) off the cable but they cost something like $150

This article will give you some perspective on cable HDTV to PC and DRM issues: When will HDTV over cable come to Media Center?



That's not true. ATI TV 650 is clear-Qam capable. Here's the link: http://ati.amd.com/products/tvwonder650/pcie/index.html
October 26, 2007 1:23:35 AM

I live in the southwest chicago area, and I get hit with the same charge but the box we have has the HDMI output on it and it has a DVR built in also. I also have a rooftop antenna (yea just couldn't get rid of it) with a converter box and my picture is crystal clear and HI-DEF, with that alone. Both TV's are LCD Panasonic 32" with tuners built in. If it wasn't for the convience of the DVR I would probally drop my TV service and go back to the antenna alone.
July 4, 2008 8:40:37 PM

docimian said:
thats the whole idea behind it. it decodes the encrypted channels, so yes you will get HBo, stars, espn, etc whatever your cable company has. and you will be able to record whatever you please, until they turn on the dreaded copy protection bit/flag/whatever. until then, happy recording!


This could not be more wrong. It is the opposite of right.

First of all, you've got a confusion of terms going on here. You can't decode encrypted channels. You decode streams that are encoded, whereas you decrypt streams that are encrypted.

The cable company sends out all of its digital channels encoded, and the majority of them are encrypted.

Encoding is to save bandwidth. It shrinks the size of the stream that is necessary to provide a decent picture. For instance, a 1080p stream that is encoded with the MPEG-2 codec is 17.8Mb/s. (Megabits per second). Computationally, it is very cheap to decode an encoded signal. It is cheap enough that your cable set-top box can do it on the fly, for whatever channel you are currently watching. A stream that is not encoded (e.g., decoded), is called a raw stream. (It is very expensive, computationally, to ENCODE a raw stream. To do it for HDTV on the fly, as in a live HD news broadcast, requires a commercial device that costs $10,000).

Now, the majority of digital content that you receive is also encrypted. Encryption is there to prevent you from gaining access to a channel that you are not authorized to see. It is very specifically a hostile addition to the data stream designed to restrict access to whatever the cable company has authorized you to have, and it serves no other purpose but to do that. And it does it very effectively, there is no way to break encryption, despite what some people-who-can't-hack-but-know-it-all will tell you. There is no way. You either have the required key, or you don't decrypt.

Your cable box has a key hidden inside of it. The cable man that installed your cable knows what that key is. Suppose the key is 555. (It isn't, and you won't be able to find out what it is, but he knows). When he installed your cable, he called up the boys back at the cable grid and said, "When a device at X address with key 555 accesses the grid and asks for the decrypt key, I want you to give it to that device for these channels that he's paying for, but not for these channels that he's not paying for".

Your cable man didn't make that phonecall for whatever widget you buy off the internet. (Nor will he). Thus it is guaranteed that that widget is not going to be decrypting anything. Indeed, the one in question in this thread does no such thing. All it can do is decode those encoded channels that are sent "in the clear", that is to say, unencrypted.

But wait, you might think, your cable box receives the decrypt key and is now able to decrypt those channels! So why not intercept the stream after it goes through the cable box? The short answer is that this doesn't work. Your cable box can and does decrypt the channels, but it only does so in a very particular way. First of all, it is not sending any decrypted channels through firewire. It only sends the clear channels through firewire. The channels that are asserting encryption will only be decrypted for you when they are being output to a HDCP compliant device. In other words, only sends the decrypted raw streams to particular devices that pass a handshake with it. Those devices are HDCP compliant devices. The only way to pass the handshake is to receive a licensing agreement from a subsidiary of intel to buy a special decoder chip. The only way to receive that licensing agreement is to agree to manufacture products which are incapable of recording the data that they receive unless the data is explicitly flagged as recordable (and nothing is ever flagged that way).

The only devices that it's going to send that decrypted, decoded stream to are basically HDTV's that are manufactured by big-chip TV companies that have signed on to the HDCP program. There is a way to strip out this HDCP using a $200 widget called the HDfury, that is basically a grey-market device available from Europe but technically illegal under the Digital Millienium Copyright Act. Somehow, the manufacturer of HDfury has got its hands of a cache of real decoder chips and that is how they do it.

Anyway, that thing is still not going to be useful to anyone want to recording of encrypted channels, because the cable box has already decoded the stream by the time it gets to the HDfury. The raw stream is far, far too big to be used in recording. It is only useful at the last second, for displaying content on the screen and then being immediately wiped from memory. (The encoded stream is 17.8 Mb/s. The raw stream for 1080p is 1.5Gb/s. That's about 1,000 times larger. Remember, it is cheap to go from encoded to decoded, but expensive the other way).

In short, there is no practical way to do-it-yourself DVR of encrypted / copyright protected digital cable.
July 4, 2008 8:48:15 PM

I have some bonus information for comcast digital cable subscribers, at least those living in New England (but this list is very likely valid or mostly valid for the entire US).

I have my set top box plugged into a linux computer running mythtv. I used a utility included with mythtv to scan all the channels that I am supposed to get with my subscription package. Its output tells me which channels are in the clear (i.e., watchable and recordable from my PC) and which are encrypted (i.e., only available when the set top box is plugged directly into a television). Here is the output, which should be useful to many of you.

clear channels:
1 VODDM
2 2
3 CN8
4 WBZ
5 WCVB
6 NECN
7 WHDH
8 PUAC008
9 LOOR009
10 LOOR010
11 WENH
12 WLVI
13 WFXT
14 WSBK
15 WBPX
16 WGBX
17 WUNI
18 WZMY
19 WNEU
20 WMFP
21 WUTF
22 LOOR022
23 WYDN
26 FAM
33 TNT
34 E
36 LIFE
37 AETV
45 CSPAN2
46 CNBC
50 ESPN2
51 NESN
52 CSNNE
53 MSNBC
54 RAI
55 SPIKETV
56 INSP
56 EWTN
56 BCTC
58 RTPI
64 TVLAND
65 QVC
70 HSN
71 WWDP
96 BET
98 LOOR098
99 LOOR099
209 WGBXDT2
211 STYLE
216 OXYGEN
217 WGBXDT4
237 WGBXDT3
249 CSPAN3
259 NHLNET
262 FCSA
264 FCSP
267 GSN
282 CMTV
283 LEAC283
284 FBN
296 WLVIDT2
297 WNBCDT2
301 HBO
403 IN3
451 PLAYBOY
453 PLAYESP
459 XCESS
505 HIPRB
506 CLASRB
507 RBSOUL
508 RBHIT
509 RAPP
510 METAL
511 MCROCK
513 CLSRCK
515 ALT
520 ADTOP40
525 MC90S
529 SMJZZ
530 JZZ
531 BLUS
532 MCRGGAE
533 SNDSCP
534 EASYLIS
535 BIGBAND
536 STANDRD
537 SHWTUN
538 CTMPCH
539 GOSP
540 MASTERP
543 MUSURB
544 SMRENG
545 MEXICAN
546 RCKESP
547 AMERCAN
548 OPRA
600 NBAPC
601 TEAM1
603 TEAM3
605 TEAM5
607 TEAM7
609 TEAM9
622 GAME2
624 GAME4
626 GAME6
628 GAME8
630 GAME10
632 GAME12
634 GAME14
680 RGTI
688 TV5MOND
715 NFLNET
717 WAPAUS
718 TMICRO
719 GALA
720 ESPND
802 WGBHDT2
807 WHDHDT
823 DSCHD
825 WFXTDT
832 HGTVD
833 TNTHD
835 USAHD
853 NFLHD
856 WLVIDT

encrypted channels:
24 DISN
25 NIK
27 TRAV
28 MTV
29 VH1
30 FX
31 TBS
32 HGTV
35 USA
38 TLC
39 DSC
40 TRUTV
41 FNC
42 CNN
43 CNNH
44 CSPAN
47 TWC
49 ESPN
57 BRAVO
59 AMC
60 TOON
61 COMEDY
62 SCIFI
63 ANIMAL
66 FOOD
67 HISTORY
68 LEAC068
69 GOLF
95 VERSUS
183 JWLTV
200 MPLEX
201 SUNDAE
202 FLIX
203 ENCR5
204 ENCR3
205 ENCR4
206 INDIE
207 ENCR7
208 HALMRK
210 NGC
212 IFC
213 TCM
214 TVONE
215 WE
218 SPROUT
219 G4
220 NIKTON
221 DCKIDS
222 TOOND
223 NOGGIN
224 THEN
225 RETR
226 DHC
227 SCIENCE
228 NIKP
229 TBN
230 FITV
231 ILIFE
232 FOXREAL
233 GRN
234 JWLTV
236 WORD
238 EWTN
239 FLIVING
240 DIY
241 BBCA
242 HISI
243 BIO
244 SOAP
245 WTHRSCN
246 BLOOM
248 ESPNEWS
250 SPEED
252 ID
253 MILI
254 CURRENT
255 OUTDR
256 FSC
257 NBATV
258 ESPNCL
260 TVG
265 NFLNET
270 LMN
271 FUSE
272 MTVHIT
273 MTV2
274 BETJ
275 VH1SOUL
276 CMTPURE
277 VH1CL
278 FMC
279 GAC
280 MTVJAMS
281 LOGO
302 HBO2
303 HBOSIG
304 HBOF
305 HBOC
307 HBOLAT
321 STRZ1
322 STRZ2
323 STRZ3
324 STRZ4
325 STRZ5
326 ENCR1
341 MAX
342 MOMAX
344 THMAX
361 SHOW
362 SHO2
363 SHOCSE
364 SHOWX
365 SHOWB
366 FLIX
381 TMC
382 TMCX
401 IN1
501 SEASON
502 TDCNTRY
503 CLCNTRY
504 BLUEGR
512 ARNHIT
514 ADALT
516 RETROA
517 ELECTRN
518 DNCE
519 LITEHIT
521 HITLIST
522 KIDZOLY
523 PARTY
524 SHWCSE1
526 80S
527 70S
541 LTCLASS
542 POPLAT
599 NBATV
701 ZEETV
702 CTIZTC
703 RTV
704 SUPCAN
705 MUN2
706 TDCES
707 CINL
708 FSE
709 CNNLM
711 MTV3S
712 VENEMOV
713 CMEX
716 HISTE
804 WBZDT
805 WCVBDT
821 NGCHD
828 MHDTV
831 TBSHD
837 AETVHD
838 WSBKDT
839 HDT
842 CNNHD
846 UHD
848 GOLFVS
849 ESPNHD
850 ESPN2HD
851 NESNHD
854 FOODHD
862 SCIFIHD
863 APLHD
868 MAXHD
870 HBOHD
872 HSTRYHD
875 STRZ1H

errored channels:
235 GMC
247 CSPAN2
261 CBSCS
263 FCSC
266 TENNIS
268 BCTC
306 HBOZ
327 STRZ6
343 ACMAX
402 IN2
435 PENT
452 FRESH
457 CLUBJEN
528 GOLDOLD
602 TEAM2
604 TEAM4
606 TEAM6
608 TEAM8
621 GAME1
623 GAME3
625 GAME5
627 GAME7
629 GAME9
631 GAME11
633 GAME13
679 RAI
681 SPTCAB
714 GOLTV
852 CSNNEHD


324 channels scanned:
125 clear channels
170 encrypted channels
29 channels errored
July 4, 2008 10:17:16 PM

This is kind of an old thread, but just FYI, the ATi 650 does support QAM and that does mean you can get some channels for free, especially on Comcast as they have a wide variety of unencrypted QAM channel.

!