[mythtv-users] Non-OTA ATSC HD Capture

Cory Papenfuss papenfuss at juneau.me.vt.edu
Thu Jul 29 11:14:10 EDT 2004


 	FWIW, I still haven't gotten closure on whether or not it's possible to 
use the BT878 chip as a generic ADC.  The gnuradio guys have some interest, but 
generally as an extension to the VBI interface in V4L by injecting staggered 
syncs into multiple cards and merging their outputs... not as a single 
streaming ADC.  Supposedly the Oren chip on the pcHDTV HD-2000 can do QAM 
demod, which will be the only hope of cable HDTV that isn't encrypted.  No 
software support for it yet, though.

-Cory

*************************************************************************
* Cory Papenfuss							*
* Electrical Engineering Ph.D. Graduate Student                         *
* Virginia Polytechnic Institute and State University 			*
*************************************************************************


On Wed, 28 Jul 2004, Michael T. Dean wrote:

> Angus Davis wrote:
>
>> I tried sending a message to the list earlier but I don't believe it went 
>> through, so I will try one more time.
>> I want to use MythTV to capture and distribute HD content from DBS 
>> networks such as Voom,  DirecTV, Digital CATV and other HD sources.  To my 
>> knowledge, there is not any hardware available to essentially take a DVI 
>> input or something of that sort to preserve a totally digital signal path. 
>> Note I am not worried here about capturing over-the-air ATSC HDTV signals. 
>> I know there are good tuner cards out there that do this (however, I am 
>> not clear on whether any of the tuner cards support the new Zenith 5th 
>> generation ATSC chipset, which significantly improves reception issues -- 
>> anyone knowledgeable on this?)
>> 
>> The only option I know about right now would be to take DVI out, put it 
>> into an SDI converter (expensive) and buy an SDI-based MPEG capture card 
>> (expensive) and pray I don't run into compatibility problems (unlikely).
>> 
>> Does anyone know of a better solution for pure-digital capture of HD 
>> signals?  For that matter, is anyone distributing an HD signal using 
>> MythTV that *isn't* coming off an OTA ATSC tuner card?
>
> Check out these threads:
> "Crazy idea for cheap HDTV tuner card" ( 
> http://www.gossamer-threads.com/lists/mythtv/users/77057 ), which seemed to 
> spawn the thread "Okay, slow down, HDTV idiot here..." ( 
> http://www.gossamer-threads.com/lists/mythtv/users/77110 )
>
> There are a lot of posts (heated topic), but in total, they explain why you 
> won't be able to capture cable/satellite HDTV now (not to mention why you 
> won't even be able to capture OTA HDTV after July 1, 2005).  Actually, you 
> should be able to capture either--even after July 1, 2005--but at a maximum 
> quality of 480p.  Basically, you'll get DVD-quality TV instead of HDTV...
>
> Mike
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