[opendtv] Re: Speaking of MPEG-4 ...
- From: Adam Goldberg <adam_g@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 16 Sep 2008 16:33:16 -0700 (PDT)
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
DataCaptions, 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 1) and (part 2) 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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