[opendtv] Re: Speaking of MPEG-4 ...
- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Tue, 16 Sep 2008 16:47:15 -0700
Adam;
I'm sorry, but my reading level has been kind of heavy the past few days.
Didn't I say early on in this thread that there was no normative reference
to CEA-608? Was I wrong on that? I guess I can run up the reference chain,
but I don't exactly have spare time at this point; new business just came in
the door.
John Willkie
_____
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Adam Goldberg
Enviado el: Tuesday, September 16, 2008 4:33 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: Speaking of MPEG-4 ...
Aw, c'mon, at least read it before saying things like there aren't normative
608 requirements....
6.4.1 Transport of Caption, Active Format Description (AFD) and Bar Data
Captions, AFD and bar data, when present, shall be carried according to
A/53, Part 4 [3], Section
6.2, as further constrained and described in 6.4.2 of this Part.
(etc).
The captioning is packaged slightly differently for AVC use (due to the
slightly different sort of picture-level user_data()), but retains all of
the '708 packet' and AFD syntax from previous.
----- Original Message ----
From: John Willkie <johnwillkie@xxxxxxxxxxxxx>
To: opendtv@xxxxxxxxxxxxx
Sent: Tuesday, September 16, 2008 12:11:26 PM
Subject: [opendtv] Re: Speaking of MPEG-4 ...
No normative reference to CEA-608 is a major change, and "allowed" is quite
different than "required." But, sometimes it seems that I'm one of the few
people that knows that CEA-608 captions are required to be passed on by DTV
stations.
John Willkie
_____
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Ron Economos
Enviado el: Tuesday, September 16, 2008 3:02 AM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: Speaking of MPEG-4 ...
I'm not sure what you mean by "no analog captions". Seems like
EIA-608 fields in EIA-708 user_data_registered_itu_t_t35 packets
are still allowed.
Also, stream_type 0x1B isn't exactly "new". It was added to H.222.0
in 2004.
Ron
John Willkie wrote:
Correction: stream_type 27/ 0x1B.
John Willkie
_____
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de John Willkie
Enviado el: Monday, September 15, 2008 1:54 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Speaking of MPEG-4 ...
The ATSC today announced the publication of ATSC Standard A/72, in two parts
(part <http://www.atsc.org/standards/a_72_part_1.pdf> 1) and (part 2
<http://www.atsc.org/standards/a_72_part_2.pdf> ) providing for the carriage
of AVC (MPEG-4, part 10) video within ATSC A/53 transport streams. I
suspect that the first real use of AVC will not be in A/53 transport
streams, in no small part due to the inability of legacy digital receivers
to deal with AVC (for the most part.) For what that use will be, you will
have to stay tuned.
But, note that there is now a new stream_type for AVC (28 / 0x1B) , and how
this information is conveyed in PSIP.
A few highlights: finally support for still pictures, and NO ANALOG
CAPTIONS, just digital ones.
There is a press release. If you'd like a copy, and it isn't available from
the ATSC web site, send me an email and I'll forward it to you. I tend to
not read press releases on this type of stuff.
I'll have support for AVC to my PSIP generator, EtherGuide Emissary, and
test the changes, before the day is out. (Turn on a dime, and give nine
cents change.)
John Willkie
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