Re: [Discuss-gnuradio] Cheap Hardware For ATSC Reception

[Daniel Schmelzer]

Hi Dave--

Again, another fair question.

Am I right that gnu-radio could decode 20 MHz worth of signal, with an audio 
card and some IF downconversion hardware?  Am I correct in thinking that 
this would be enough for 3 ATSC channels at one time?  This would be useful 
for picture-in-picture or timeshifting functions.

Of course, you could use multiple WinTV-HD cards to do the same functions, 
but I doubt that you would ever get a Hauppauge driver good enough to play 
nice in this scenario.

Another possibility is that ATSC boards will come out that are similar to 
the Pinnacle PCTV Sat, i.e. simplified and based on a chipset that is well 
known by the open source community.  While these don't yet exist, they would 
run at about $150 apiece at minimum and would just contain the tuner, IF 
downcoverter, demodulator, and bridge.  Multiple concurrent channels would 
require multiple boards.

Re programming an open source driver for the WinTV-HD, I wish you luck.  I 
would love to see it.  But Teralogic, the manufacturer of the TL880 
bridge/MPEG-2 decoder that is used in the WinTV-HD, HiPix, and MyHD, has 
been very tight with the necessary info.  I have a list of chips on all of 
these cards...

http://www.schmelzer.org/dschmelzer/hipix_chips.htm
http://www.schmelzer.org/dschmelzer/accessdtv_chips.htm

A WinTV-HD list is availabe upon request.

At a threshold level, I guess it comes down to how much CPU and memory 
bandwidth is required by the radio program.  When I wrote to the list a 
couple of days ago, I had dreadfully unrealistic expectations about what 
would be required.  In the meantime, some off-list discussions have adjusted 
my expectations by an order of magnitude.  20 Msamples @ 12 bits apiece is a 
lot of data to process.

Regards--

Dan

>         There is a later board with a HD MPEG-2 chip on it called a
> Win-HD that capable of HD to RGB decoding and supposedly ITC HD
> transport stream to PCI copy.
>
>         As far as I know this board is still current (at least I was
> able to purchase one on the web recently, and several distributors
> offered them a month ago).   What with the copy protection working group
> agreements I am not sure how long the board will be available but last I
> knew the latest version of the Hauppauge Windoze software could capture
> the transport streams unencrypted into files and play back from those
> files.  They appear to have implemented a crude DVR for HDTV in fact.
>
>         I haven't had time to look into the chips on the Win-HD, and
> would be very interested in whether anybody else has started to figure
> out a programmers model for it.  I might be inclined to start playing
> with coding a Linux driver if someone could supply any clue as to how to
> program the card (eg documentation of the chip APIs).  It does come with
> a Windoze application, and given a lot of pain (I hate pain) it might be
> possible to reverse engineer the required information (I have done that
> kind of thing in a previous life, but I don't exactly relish the
> prospect).   And if anyone else is working on a driver, I might be able
> to help a bit on that as well...
>
>         The Win-HD retailed via national websites at around $414 or so
> last I checked, BTW, so it is a little bit more expensive than the older
> board.   But it will do ATSC HDTV to RGB conversion (not sure about
> YCrCB) in a variety of formats.
>
>         And I suppose the obvious need not be stated - if one wants ATSC
> decoding capability (for LEGAL fair use !!) one had better act now
> before the door is forever closed and any device or technique to do so
> is regarded as a DMCA circumvention device and criminalized.  It seems
> clear that it is unlikely that existing devices will become  illegal -
> but future ones are almost certain to...
>
>
> --
>         Dave Emery N1PRE,  address@hidden  DIE Consulting, Weston, Mass.
> PGP fingerprint = 2047/4D7B08D1 DE 6E E1 CC 1F 1D 96 E2  5D 27 BD B0 24 88 
> C3 18
>
>
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