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Non-OTA ATSC HD Capture

 

 

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angus at tellme

Jul 28, 2004, 1:53 PM

Post #1 of 9 (2320 views)
Permalink
Non-OTA ATSC HD Capture

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?

-angus
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mtdean at thirdcontact

Jul 28, 2004, 6:11 PM

Post #2 of 9 (2292 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

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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angus at tellme

Jul 28, 2004, 8:35 PM

Post #3 of 9 (2302 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

On 7/28/04 6:11 PM, Michael T. Dean wrote:

> 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...

Too bad. Big-ass DVI-D w/ HDCP switcher here I come. I can still use
MythTV to act as my movie content server (ripped from DVD), which is
really what I new for certain I wanted to use it for anyway. It is
still a cool alternative to Kaleidescape or the AMX MVP for someone not
afraid of a little hacking. That is, until around 2009 or whenever
someone pulls a DeCSS on the HDTV encryption scheme. Thanks for the tip,
-angus
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mtdean at thirdcontact

Jul 28, 2004, 9:02 PM

Post #4 of 9 (2295 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

Angus Davis wrote:

> That is, until around 2009 or whenever someone pulls a DeCSS on the
> HDTV encryption scheme.

Actually, the broadcast flag regulations allow for the revocation of
"substantially compromised" security measures. In other words, once
HDTV Jon ;) cracks the HDCP, the FCC can revoke that measure and replace
it with another. The question is who's faster, the FCC or the crackers???

Mike

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papenfuss at juneau

Jul 29, 2004, 8:14 AM

Post #5 of 9 (2286 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

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
> _______________________________________________
> mythtv-users mailing list
> mythtv-users[at]mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>


brandon+myth at linuxis

Jul 29, 2004, 9:00 AM

Post #6 of 9 (2292 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

> 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

Not true. The July 1st date is for _Selling_ hardware that does not
support HDCP protection. You can capture HDTV and ignore the copy right
bit all you want with current hardware. Most HDTV set top boxes don't
support HDCP and making people go out any buy a new set top box would
make too many people unhappy.

EFF is starting a movement to fight HDCP and is supporting cards like
the pcHDTV HD2000 card. This card just ignores any copy right bit and
gives you the data without any limitation. You can use these cards
forever in the future, but it will be illegal to sell them after July
1st 2005. So before that date comes, and if the EFF hasn't made any
advancement in keeping HDTV tuner cards legal, consider getting a HDTV
card before you can't buy them. One way people may be able to sell HDTV
tuner cards for a computer is to not allow showing more than a 480P
stream, or taking 720P/1080i streams and real-time transcoding them
(This won't be cheap/easy to do in hardware) down to 480P.

For a device to support HDCP you have to guarantee that at no point can
the data be captures "as is" in HDTV format and be moved off of the
device. This is very hard to do with a computer as if the data touches
the PCI bus you can get to it. HDTV Tivo's will be interesting to see
if they support HDCP as if you can hack into the Tivo easily and get to
the data it won't be HDCP certified and will be illegal to sell. I'm
sure several HDCP boxes will get the sticker and will still be breakable
and people will get to the content. I'm not sure what the FCC will do
if this happens. But, this is why HDTV on a computer and with Myth may
be limited to only those who bought the cards when they are/were still
legal.

--Brandon


mtdean at thirdcontact

Jul 29, 2004, 1:06 PM

Post #7 of 9 (2295 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

Brandon Beattie wrote:

>>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
>>
>Not true. The July 1st date is for _Selling_
>
and _importing_ (so you can't even buy from overseas vendors)

> hardware that does not
>support HDCP protection. You can capture HDTV and ignore the copy right
>bit all you want with current hardware.
>
Which is all explained in the links I gave. I was just giving the
"attention-grabbing headlines" to provide some motivation for reading
through all the posts (because there was a lot to read, and just reading
a few wouldn't give the whole story) so I wouldn't have to repeat it all.

>I'm
>sure several HDCP boxes will get the sticker and will still be breakable
>and people will get to the content. I'm not sure what the FCC will do
>if this happens.
>
Well, since the FCC learned from the DVDCCA fiasco that even "the
world's best encryption algorithm" (DVDCCA's opinion, definitely not
mine) is vulnerable to compromise, they have provided for the revocation
of "substantially compromised" technological measures. Therefore, if
the political fallout of admitting that HDCP has been compromised is
less damaging than Hollywood's "gloom and doom" prophecies of the end of
movies/TV (or, put another way, if Hollywood pays the politicians enough
to help them cover their embarrassment/rationalize acting against the
best interests of their constituents--which seems to have worked with
the broadcast flag itself), the FCC will revoke HDCP as an authorized
technological measure.

IANAL, but my understanding of the final ruling (
http://www.eff.org/IP/Video/HDTV/Final_Rule_FCC-03-273A1.pdf ) is that,
basically, someone will petition the FCC for the removal of some
"approved technological measure" from "Table A" (Table A is the list of
approved technological measures at the end of the broadcast flag
regulations--which is meant to be easier to change than the regulations
themselves). They must explain the extent to which the technology has
been compromised and demostrate that in its compromised form, it is less
effective than other Table A technologies at protecting content. The
FCC will then make a determination whether to revoke the measure and
then seek comment on the "appropriate standard for revocation."

"Once a content protection or recording technology has been revoked, we
seek comment on the appropriate mechanism by which revocation should be
effectuated. For example, should revoked content protection or recording
technologies be eliminated on a going-forward basis, while preserving
their functionality for existing devices? We also seek comment on
whether there are technological or other means of revoking content
protection or recording technologies while preserving the functionality
of consumer electronics devices."

Which doesn't sound too bad... Doesn't that mean if I buy a component
that works and they later revoke a technology used by that component,
they will "grandfather" it in so I don't have to buy a new component?
No. Even if they do grandfather existing technological measures, you'll
most likely still have to buy new components.

The 5C technologies are the initial technologies which are expected to
be approved for use with the broadcast flag, and includes HDCP. Since
the 5C technologies only perceive a system to be secure if every
component of that system is 5C compliant, all future technologies added
to Table A will probably act the same (refusing to be Table A compliant
if non-compliant devices are detected). Therefore, once the FCC revokes
a technology, all new devices (post-revocation) will see the revoked
technology as non-compliant with Table A requirements. Therefore, once
you buy a new component and plug it in to your existing system, the new
component will act as a non-compliant device--because of your "insecure"
grandfathered devices--which will cause your grandfathered devices to
act as non-compliant devices--because of your "acting insecure" new
device. Catch 22. Or, would that be Catch FCC 03-273?

So, each time a measure is revoked, you have two choices--1) never buy
any new components or 2) buy all new components. Remember, when I say
all components, this means TV's, OTA/cable/satellite receivers, A/V
receivers, recorders, network switches, and anything else that touches
the digital data. Therefore, "unplugging the grandfathered device"
would mean you would probably need a pre-grandfathering TV to use with
the grandfathered device and a post-grandfathering TV to use with the
new device. And, you would also have to duplicate all other devices you
plan to use on your system. In other words, two systems... (Then
three, then four...)

It's theoretically possible that someone will come up with a way to use
software or firmware updates for providing the content protection to
allow for updating the device as measures are revokes, but a device
using non-hardware-based content protection, itself, would be
significantly easier to compromise than devices using hardware
implementations. Therefore, it would be much more difficult for that
device to achieve approval. Also, since many of the electronic
components within the device will probably use hardware-based
protection, it would be very difficult to make the device continue to
work after a revocation. If the components of the device do not use
hardware-based protection, the device would provide easy access to
non-compliant components, which would allow people to build
non-compliant devices, so the device would be unlikely to receive approval.

Of course, talking about compromise may be a moot point, anyway, as the
DMCA makes it a federal felony offense to attempt to circumvent, own any
technology to circumvent, or use any technology to circumvent any of
these technologies. So, the FCC would be doing the RIAA's work of suing
the public.

Fortunately, I think once this happens a couple of times (or possibly
even once)--and people have to go out and buy new components a couple of
times--enough people will know just how wrong this legislation is to
cause such a public outcry that even Orrin Hatch (
http://www.eff.org/IP/Apple_Complaint.php among others ), Fritz
Hollings, Ted Stevens, Daniel Inouye, John Breaux, Graham Nelson, and
Dianne Feinstein (
http://www.eff.org/IP/SSSCA_CBDTPA/20020321_s2048_cbdtpa_bill.pdf ) and
other "we have a country full of theives" politicians to rethink the
broadcast flag regulations. Unfortunately, that means that those of us
doing MythTV may not get HDTV until 2010 (if you're being optimistic) or
2015 or beyond...

>But, this is why HDTV on a computer and with Myth may
>be limited to only those who bought the cards when they are/were still
>legal.
>
>
And only to OTA HDTV channels. Even if someone eventually gets QAM
support working on the pcHDTV, the only channels satellite/cable
operators would consider sending unencrypted are OTA channels, and most
operators are choosing to encrypt even the OTA channels. However, I
agree with your point. It's well worth buying a $200 pcHDTV card
now--even if you don't have the high-def antenna and/or high-def TV.
It's also worth reading up on these issues at the EFF (
http://www.eff.org/broadcastflag/ and http://www.eff.org/issues/drm/ and
http://www.eff.org/issues/dmca and many more) and actually getting
involved ( http://action.eff.org/ ).

Mike
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papenfuss at juneau

Jul 29, 2004, 1:47 PM

Post #8 of 9 (2288 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

>> But, this is why HDTV on a computer and with Myth may
>> be limited to only those who bought the cards when they are/were still
>> legal.
>>
> And only to OTA HDTV channels. Even if someone eventually gets QAM support
> working on the pcHDTV, the only channels satellite/cable operators would
> consider sending unencrypted are OTA channels, and most operators are
> choosing to encrypt even the OTA channels. However, I agree with your point.
> It's well worth buying a $200 pcHDTV card now--even if you don't have the
> high-def antenna and/or high-def TV. It's also worth reading up on these
> issues at the EFF ( http://www.eff.org/broadcastflag/ and
> http://www.eff.org/issues/drm/ and http://www.eff.org/issues/dmca and many
> more) and actually getting involved ( http://action.eff.org/ ).
>

Which brings up the point of QAM on the pcHDTV. I emailed support, and
they said that the OREN OR1211 chip that they're using supports QAM. They
haven't gotten it to work, but I don't know how hard they've tried. I also
don't know the development environment (anything proprietary in the drivers or
hardware?).

I suspect that with the broadcast flag enforced for copy "protection,"
and QAM for closed-circuit bandwidth conservation, cable companies might start
broadcasting unencrypted QAM channels. I thought that FCC et al. wanted to
have consumer-grade "HD cable-ready" TV's and such to work without magic settop
boxes. The broadcast flag allows for unencrypted, but "protected" streams to
come down the wire to a cable-ready tv. Of course I could be all wet and
they'll require a magic box to get *anything* over the cable soon.

-Cory


jcaputo1 at comcast

Jul 30, 2004, 7:25 AM

Post #9 of 9 (2295 views)
Permalink
Re: Non-OTA ATSC HD Capture [In reply to]

On Thursday 29 July 2004 16:47, Cory Papenfuss wrote:
> I suspect that with the broadcast flag enforced for copy
> "protection," and QAM for closed-circuit bandwidth conservation,
> cable companies might start broadcasting unencrypted QAM channels. I
> thought that FCC et al. wanted to have consumer-grade "HD
> cable-ready" TV's and such to work without magic settop boxes. The
> broadcast flag allows for unencrypted, but "protected" streams to
> come down the wire to a cable-ready tv. Of course I could be all wet
> and they'll require a magic box to get *anything* over the cable
> soon.


I thought that the FCC mandate was to allow for digital-cable-ready
devices that would simply require a 'key' card to be plugged in to
allow decrypting the signal from a particular provider. It eliminates
the need for a particular set-top box, but doesn't eliminate the issue
of encryption.

-JAC
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