What's needed to receive HDTV from Comcast?

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.
13 answers Last reply
More about what needed receive hdtv comcast
  1. 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?
  2. 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
  3. 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
  4. 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.
  5. 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.
  6. 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.
  7. With the cablecard can you pick up the encrypted channels as well. Discovery, ESPN, etc.?
  8. 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!
  9. 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
  10. 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.
  11. 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.
  12. 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
  13. 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.
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