Question about hdtv capture in the US

[chadamir]

I recieve my hdtv service through the cable company's digital cable. They provide said service via a digital cable box with an hdtv tuner in it. I believe that this box is the only way to access these channels, but I could be wrong. Does anyone have any ideas as to how I would be able to capture from these channels? I had an idea that I could just use the box and then output to an hdtv capture card with an rca wire rather than hooking the cable directly up to the card. Anyone know if this would work? My cable provider is comcast.

[MentholMoose]

If your cable provider uses 8VSB modulation for their HDTV channels then you can just connect the cable to an HDTV card designed for OTA HDTV. However most cable companies use a modulation scheme called QAM, which is incompatible with 8VSB, and there are currently no HDTV cards that support QAM (AFAIK).

[trbarry]

The Hauppauge WinTV-HD claims hardware support for unencrypted QAM but they never wrote the software for it, and maybe never will.

And the Dvico Fusion III is supposed to support unencrypted QAM also, if it is ever released.

Meantime I think you can only record via analog.

- Tom

[FredThompson]

What about this? http://www.jvc.com/product.jsp?productId=PRD4603000

[SeeMoreDigital]

Good God what a claim by JVC...

Can Record Any Type of Broadcast including HD, SD or Analog

I'll keep saying it. You guys in North America get all the good toys first!

I don't think it's even possible to capture any form of a digital cable signal over here in the UK.

NTL use Nagravision encryption and I don't know about the other companies.

[FredThompson]

My understanding is you can capture the signals using some custom Linux software. A few weeks ago there was a post about this on Slashdot but the PC card was also around $2000. That's all I know, unfortunately. Probably a hush, hush thing where you gotta be in the club, dontcha know.

[trbarry]

I think that /. article was on "software radio". There is a web site about it somewhere that can probably be found with a search and I think even a couple Doom9 threads. But I thought they were only doing 8VSB so far, not QAM for cable.

- Tom

[FredThompson]

Maybe it was, I don't remember. The cost of entry was too high for me, especially given that JVC unit. I've also rumblings of something done by a German hacker group but don't know much more than that.

[SeeMoreDigital]

Thanks for the info,

I will hunt it down and give it a read 'for educational purposes only' you understand!

I don't know.... digital cable. Much more clever than analogue cable!

Well over my head and pocket!

[trbarry]

BTW, I don't think this even has to be a subject for grins and elbow nudges. AFAIK, many of the companies sending HDTV over cable are using unencrypeted QAM for the non-premium channels. That would include what I've been told by the Comcast guys in my area.

If it could be made to work software radio for unencrypted QAM would be competelely legal but would not unencrypt anything requiring an access card. That's a completely different can of worms.

- Tom

[SeeMoreDigital]

Thanks Tom

Unfortunately, I think digital cable users in the UK will be out of luck, as I'm sure every digital channel that goes down the pipe is encrypted with Nagravision.

As I say, you guys in...............

Cheers

[Entropy512]

Originally posted by trbarry
I think that /. article was on "software radio". There is a web site about it somewhere that can probably be found with a search and I think even a couple Doom9 threads. But I thought they were only doing 8VSB so far, not QAM for cable.

- Tom
Gnu Radio perhaps? http://www.gnu.org/software/gnuradio/

It requires some very expensive hardware (They're using an IF sampling ADC), and isn't anywhere close to realtime.