[opendtv] Re: Q on digital OTA broadcasts

  • From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Sun, 4 Nov 2007 17:16:46 -0800

Violations of FCC rules should be reported to the FCC as such, but you're
more likely to get the station chief engineer to fix things.

The only way I know of to send this type of data is in line 21, as an XDS
data field in the CEA/EIA-608 data. (field 1 or 2).  I only have the (yet to
be released next edition of CEA-608; there CGMS-A is in section

The text is quite lengthy; too long to copy here, and to do so at this point
would be premature as the document is being worked on by at least two groups
and isn't final, and could put me into trouble with SMPTE's non-disclosure

I guess I don't follow this area very closely (I only reference the captions
in the caption_service_descriptor), but I'm wondering under just what rule
the FCC has supposedly mandated that the FCC has stated one cannot set "copy
never."  The rules and the FCC's texts are what matters, not what is merely
cited on the FCC web site (which is merely informative.)

The (somewhat) equivalent data in digital is the redistribution control
descriptor, which the FCC tried to mandate the use of in dTV sets, but was
shot down in the courts.  Broadcasters are free, however, to set the
redistribution control.

It's very rare that a broadcast engineer would set something to a value not
permitted by the FCC, particularly in the FCC's home market.   It's possible
that one of the -608 or -708 boxes has these fields set to the most
restrictive value, by default.

However, I don't see how going to S-video would strip out line 21, so you
just have a device downstream that doesn't care about CGMS-A.

The spec mentions that the use might be affected by private agreements, so I
think you are actually talking about receiver implementation issues.  I
would be very interested in seeing the actual data transmissions.

I "think" all you have to do is to strip out line 21, but I don't really do
analog.  Anymore.

John Willkie

-----Mensaje original-----
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Manfredi, Albert E
Enviado el: Sunday, November 04, 2007 4:26 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Q on digital OTA broadcasts

I've been considering a Philips combo DVDR/PVR for Christmas. But in the
owner's manual, it says something about copy protected broadcasts won't

In the past, when using an NTSC-only Philips DVDR, I discovered that
many local broadcasters (apparently) set the "copy never" code in their
analog broadcasts, in spite of the fact that the FCC has said time and
again that time-shift recording is supposed to be allowed ALWAYS. I seem
to have been able to sidestep this limitation by sending baseband video
from an ATSC STB to the Philips recorder, using an S-video interface, so
this hasn't been an issue for me in about the past three years. But I
know that this gremlin is still lurking there in the background

So, my question for broadcasters is, how are the ATSC transmissions
encoded? Copy once? Copy never? Is this going to make me want to write
letters to the FCC to get working right?

If you tell me that I'm better off to keep doing what I'm doing now, I'm
sure I can find other things to spend my money on. Not looking for

Many thanks for any informed replies.


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