Sounds like the quantum mechanical joke our secretary told me the other day. If a man says something in a forest and there is no woman around to hear him, is he still wrong?
- Tom Mark A. Aitken wrote:
Guys, guys, guys! In the real world I would argue that the lines between analog and digital are 'smeared'. In the digital world, there exists in reality a 'rise time' and 'fall time'. In between the high and low values it would appear that analog exists as a way to make digital happen. Are we arguing 'wave theory' or 'particle theory'? Sounds to me like we have a wave–particle duality. Perhaps we need the equivalent of a "quantum mechanics" construct to end this debate?:-) Mark On 9/16/2008 7:28 PM, John Willkie wrote:Does "symmetrical sine wave" sound digital to you?I believe you are confusing coding with mapping. NRZ/NRZI, etc would be a way of coding an analog component in a digital form (and vice-versa) with the changes from one state to another signaling 1 or 0 (depending on the clock, etc.) But, here's the rub -- per A/53, these "analog" captions will be present in fully digital signals for many, many years to come, to support legacy analog decoder devices. Or, so the rational goes ... John Willkie -----Mensaje original----- De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En nombre de Tom Barry Enviado el: Tuesday, September 16, 2008 3:31 PM Para: opendtv@xxxxxxxxxxxxx Asunto: [opendtv] Re: Speaking of MPEG-4 ... John Willkie wrote: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.Tom; I'm sorry, you've disintermediated yourself from reality. Have you ever read CEA-608?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. ;-) - TomHere'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 whatCEA-608captions 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 modulationisFreeLists.org-- 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 WillkieYou can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings atFreeLists.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- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the wordunsubscribe in the subject line.----------------------------------------------------------------------You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings atFreeLists.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.-- <>< <>< <>< <>< <>< <>< <><Regards,Mark A. Aitken Director, Advanced Technology =================================== Sinclair Broadcast Group 10706 Beaver Dam Road Hunt Valley, MD 21030 =================================== Business TEL: (410) 568-1535 Business MOBILE: (443) 677-4425 Business FAX: (410) 568-1580 E-mail: maitken@xxxxxxxxxx www.sbgi.net =================================== "The best executive is the one who has sense enough to pick good men to do what he wants done, and self-restraint to keep from meddling with them while they do it." ~ ~ ~ ~ Theodore Roosevelt ~ ~ ~ ~ =================================== "Leadership is the art of getting someone else to do something you want done because he wants to do it." ~ ~ ~ ~ Dwight Eisenhower ~ ~ ~ ~ =================================== "Delegating work works, provided the one delegating works, too." ~ ~ ~ ~ ~ ~ Robert Half ~ ~ ~ ~ ~ ~
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