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mpeg4everybody
26th January 2003, 11:39
Hi,

Could someone tell me how i can capture digital cable channel.

I'm in the US so this would be, I guess, ATSC digital (not DVB).

Thanks.

rmatei
26th January 2003, 19:29
An ATSC card like HiDTV or HiPix can be used to capture digital stuff from an antenna. AFAIK there's no way to capture stuff digitally from digital cable, as those streams are encrypted and often not even ATSC-compliant. Your only option would be to capture the analog signal from your set top box.

mpeg4everybody
27th January 2003, 02:40
Originally posted by rmatei
An ATSC card like HiDTV or HiPix can be used to capture digital stuff from an antenna. AFAIK there's no way to capture stuff digitally from digital cable, as those streams are encrypted and often not even ATSC-compliant. Your only option would be to capture the analog signal from your set top box.

Hum... too bad...Are you sure ? I would have though that at least the non-premium channel would not be encrypted....

My set-top is a motorola DCT-2000, I could'nt find a lot of spec about it but it's classified in the ATSC digital set-top category on Motorola's website...

The bad thing about digital cable is that you got only one tuner so you cannot even record a channel and watch another at the same time...

I wish i could reverse enginer this box... but before I start talking about this, is this the right place to talk about this ?

Thanks..

mpeg4everybody
31st January 2003, 13:46
OK, after looking around a bit i came up with some info.

Digital cable in the US (well at least mine) is using QAM 64/256 modulation, which i think is the same as DVB, so it _may_ be possible to use a DVB card to capture some digital cable streams. I'm still looking for more information....

trbarry
31st January 2003, 14:46
Most cable companies are using QAM.

Hauppauge has advertised for 2 years now that their WinTV-HD card has (hardware) support for QAM but they have yet to implement software for it. Who knows if the ever will? Mines been sitting on the shelf for over a year now.

There is also a Fusion something or other card from Dvico that does software only decoding on faster machines. They claim the next version of the card will (may?, hope?) have QAM support.

I've got Comcast HDTV now and the installer told me the non-premium HDTV channels are unencrypted QAM. So I'm waiting.

- Tom

goemon
10th February 2003, 00:38
QAM is just the modulation. there's a proprietary bitstream (it's not DVB-C) on top of that. :mad:

i've already looked into this, seems the only way to capture digital broadcasts in north america is either from DVB-S or aerial broadcast ATSC (if you are lucky enough to have it in your area). the cable companies have gone to great lengths to ensure you can't capture their stuff. :angry:

if it really were that simple, someone would have done it by now :(

mpeg4everybody
11th February 2003, 08:30
Originally posted by goemon
QAM is just the modulation. there's a proprietary bitstream (it's not DVB-C) on top of that. :mad:

i've already looked into this, [...]

Where you able to capture this proprietary bitstream ? What did you use ?

I belive somewhere behind this proprietary stuff there is still a mpeg2 transport stream. I would like just to start taking a look a t this bitstream...

goemon
13th February 2003, 19:39
Originally posted by mpeg4everybody
Where you able to capture this proprietary bitstream ?

no

KentBrockman
17th February 2003, 17:38
So, can you still capture the digital cable via the output channel on the back of the digital box? would quality be that much worse? Also - can hi def recordings still be captured this way (albeit, lower resolution I assume)?

Any guides to capturing from digital cable boxes?

thanks

goemon
17th February 2003, 19:56
Originally posted by KentBrockman
So, can you still capture the digital cable via the output channel on the back of the digital box?

you can capture via composite outs (very few digital boxes even have svideo outs), but it's analogue capture. also, it is possible some programs are protected with macrovision.,,

would quality be that much worse?

yes, much worse than capturing digital bitstream.

it's like capturing DVD with analogue. if quality wasn't so bad with this method, people wouldn't be using DVD ripper software all the time.

Also - can hi def recordings still be captured this way (albeit, lower resolution I assume)?

no. hi def recordings cannot be captured at all.