[opendtv] Re: Speaking of MPEG-4 ...

  • From: Tom Barry <trbarry@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Tue, 16 Sep 2008 06:13:52 -0400

Technically I'm not sure EIA-608 captions ever really were analog. IIRC, the line-21 waveform is decoded to represent 2 binary bytes per field. Does that make it analog, any more than ATSC? It seems more like early digital to me, just not very dense.


- Tom


Ron Economos wrote:
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 <http://www.atsc.org/standards/a_72_part_1.pdf>) 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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