[mythtv-users] Specs

[Jarod C. Wilson]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thursday 08 January 2004 22:31, Brad Allen wrote:
> From: "Joseph A. Caputo" <jcaputo1 at comcast.net>
> Subject: Re: [mythtv-users] Specs
> Date: Thu, 8 Jan 2004 16:55:54 -0500
>
> Your message was helpful, although there are some corrections I'm
> going to make.  I have both a pcHDTV HD-2000 and a Hauppauge 990
> WinTV PVR 350.

And I have some further corrections I'm going to make to your incorrect 
corrections. ;-) (along with some additional input)

> pcHDTV HD-2000 does NOT do nor has HW compression;
> however, ATSC is already compressed, somewhere before it hits the
> broadcaster's antenna, so what you receive is already compressed.  No
> cable companies send out ATSC that I know of

Um, yes they do. I have a Motorola DCT-5100 cable box provided by Comcast, 
hooked via component video to a High-Definition TV set, complete with quite a 
few channels of High-Definition programming...

> so this is air-antenna only

The pcHDTV can only receive terrestrial broadcast High-Def programming, 
because cable uses a different encoding algorithm (QAM) than broadcast (which 
for the record, uses 8VSB). Note that this is also true of most HD sets with 
built-in HD tuners, as well as those stand-alone tuners. There is work 
underway to create dual mode (8VSB and QAM) tuners, but there aren't many (if 
any) readily available today.

> It [the pcHDTV card] does
> however have some special ability to receive ATSC; apparently, the HW
> actually does something useful to effect that (perhaps DSPing the
> received waves into digital, perhaps including minimally verifying
> that that digital is a possibly useful digital signal and tuning it
> just a bit?  Or maybe not ...).  SW does the rest, but SW doesn't have
> much to do with ATSC streams (until display decoding) ... so little,
> it seems, that pcHDTV seemed to just dump HD-2000 on the market with a
> base driver and SW set, and we're doing pretty well smudging our
> fingers in the SW to get it to work pretty well (and because it's not
> hidden code & spec, there's really no big mysteries, and no quirks
> like @*##&!! #^&*@&#^ IVTV driver --- and much less SW effort is
> needed to get HD-2000 to work, compared to IVTV driver --- look at the
> # of poeple working on IVTV -- a lot, compared to HD-2000).

The pcHDTV card more or less joins a broadcast domain similar to a network 
multicast domain, so I believe it actually operates much more like an 
additional network interface on your system, and all it does is dump the 
stream of stuff its receiving either to your hard drive or to the screen 
(through a program capable of decoding an mpeg2-transport stream).

> > Check elsewhere for the availability of cards that can receive HDTV
> > over cable; I don't think there are any available in the U.S.

There aren't any for the consumer market, no. Not yet, anyway. Still waiting 
on those VIA 733 systems w/dual QAM tuners to get here...

> Very little is necessary to turn ATSC stream into program streams
> (such as MPEG stream) --- so little, that Xine, Mplayer (thus
> mencoder), and Myth already all have support for that, and probably
> lots of other transcoders as well.  (Result is a data stream from the
> broadcaster, usually MPEG2 (well, it says "mpeg1/2" when I've looked,
> but I'm assuming it's MPEG2) and some audio stream (AC3 on one).)

They're all mpeg2-ts. Converting to an mpeg2-ps is simply a matter of dropping 
the extra video and audio channels you don't want.

> > The PVR-350 won't help in the decoding for that, because AFAIK it
> > will only decode up to DVD-resolution (720x480 or whatever).
>
> ... a bit higher for PAL, I think ... (is it true that '350s are
> target built, in such a way that my '350 won't work in PAL land by me
> just setting new SW & driver settings, or is that false?) ...

Its just a driver setting to switch between NTSC and PAL. And yes, PAL res is 
a touch higher (720x576 vs 720x480).

> BTW, most ATSC streams where I live are NOT HD, and are NOT 16:9 or
> other than ~4:3 aspect ratios.

Um, yes those 4:3 broadcasts are in fact considered HD. They just aren't 
top-of-the-line HD. There are 18 different HD "standards" and one of them is 
480p, which is usually just your basic NTSC signal de-interlaced before its 
broadcast. Lots of broadcasters do that for basic programming (talk shows, 
news, etc.) and only broadcast full-out max-rez HD for prime-time 
programming. But its all HD.

> The main reason I jumped to get the HD-2000 card, though, is the
> Broadcast Flag; apparently, because so few of us will have access to
> HW like HD-2000, broadcasters will continue to broadcast unencrypted
> video, but it won't be legal to buy HD-2000 cards after 2004.  I plan
> to stock as many as I can afford between now and then.

Who exactly says it won't be legal to buy HD-2000 cards after 2004?

> If someone else makes a good used market by buying more than they want
> right now, that'd sure make me feel more secure ... but at $200 each
> (rounding up; I think it's $190 or $180 or something), they are a bit
> pricy for a bare-bones no big codecs card (which only receives
> antenna).  I still want a whole bunch ... two for every local
> broadcaster for every house I might live in (a cold spare for each
> active one in use, with full channel coverage in every location).  For
> this house, that's four channels times two (for the cold spares), and
> for another house it has to be more since it's closer to more
> broadcasters, so about half a dozen to a dozen times two ... somewhere
> between 8+12 and 8+24 cards will do fine (that's 20 ... 32 cards,
> which at $200 each is $4,000 ... $6,400 ... ugh.  I'll get my car
> first.  Like I said --- as many as I can afford, not as many as I want
> ...)

Methinks you're a bit too paranoid, and/or watch too much TV if you think you 
need that many... ;-)

> The idea is that there will be a lot of ATSC broadcasters soon, no
> matter what, so no matter what, we can find a use for our HD-2000s,
> unless and until they start doing encryption, which is a big question.

I don't think its that big a question. They won't. There are too many folks 
out there with rather expensive equipment that wouldn't work anymore if 
broadcasts were encrypted. All the HDTV tuners and HDTV sets with built-in 
tuners would be obsoleted, so don't expect to see that happen. The industry 
is already having a hard enough time getting everyone to switch, so they 
aren't going to do something drastic like that...

- -- 
Jarod C. Wilson, RHCE

Got a question? Read this first...
     http://catb.org/~esr/faqs/smart-questions.html
MythTV, Fedora Core & ATrpms documentation:
     http://wilsonet.com/mythtv/
MythTV Searchable Mailing List Archive
     http://www.gossamer-threads.com/archive/MythTV_C2/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (GNU/Linux)

iD8DBQE//y8rln8CX+oYdJURAokWAJ4kkQzOYDlAQqFgQi1a6SvliqPKSgCgycYy
py57F1+QJrGlOIHM5sZiMeA=
=7R43
-----END PGP SIGNATURE-----