"analog captions" = "captions for analog video", CEA-608 "digital captions" = "captions for digital video", CEA-708 (and yes, of course, 708 packets can carry 608 data) Don't take the 'analog' literally. Heck, don't take the 'captions' literally either - CEA-608 includes lots of other stuff, too: XDS, CGMS-A, etc. ----- Original Message ---- From: Tom Barry <trbarry@xxxxxxxxxxx> To: opendtv@xxxxxxxxxxxxx Sent: Tuesday, September 16, 2008 6:31:25 PM Subject: [opendtv] Re: Speaking of MPEG-4 ... John Willkie wrote: > Tom; > > I'm sorry, you've disintermediated yourself from reality. Have you ever > read CEA-608? > Yes, for one project I wrote software to create the needed Line 21 waveform for a D/A converter. I still have my copy of CEA-608C. And you can go re-intermediate yourself by seeing section 5.2 of the same document which begins "Figure 2 shows the signal waveform. The Clock Run-in is a symmetrical sine wave with its maximum and minimum amplitudes being equal to the logic "1" and "0" levels respectively of the encoded data. ...". Then there is a pretty picture in Figure 2 to explain it. Smells pretty digital to me. ;-) - Tom > Here's from section 1.1 > > "CEA-608-D is a technical standard and guide for using or providing Closed > Captioning services or other data services embedded in line 21 of the > vertical blanking interval of the NTSC video signal." > > Does that sound "analog enough" for you? Vertical blanking intervals and > NTSC are "characteristics of analog video" and are distinguishable from > characteristics of digital video. > > You see, I wasn't referring to how the captions are coded, but what CEA-608 > captions describe: words spoken in an analog television channel. The > carriage of analog captions in 8-VSB program services will last long after > analog television sunsets. > > In industry shorthand, there are "analog" and "digital" captions, > corresponding to CEA-608 and CEA-708, respectively. > > Using your argument, there is no digital television, since all modulation is > -- by definition and reality -- analog. (With the possible exception of > dit-dah over a telegraph line.) > > John Willkie > > > > -----Mensaje original----- > De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En > nombre de Tom Barry > Enviado el: Tuesday, September 16, 2008 3:14 AM > Para: opendtv@xxxxxxxxxxxxx > Asunto: [opendtv] Re: Speaking of MPEG-4 ... > > 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 >>> >>> >>> >>> >>> > > > > ---------------------------------------------------------------------- > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > - Using the UNSUBSCRIBE command in your user configuration settings at > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word > unsubscribe in the subject line. > > > > ---------------------------------------------------------------------- > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > - Using the UNSUBSCRIBE command in your user configuration settings at > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word > unsubscribe in the subject line. > > ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.