Talk:ATSC standards

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Colors of pictures/graphics for better usability!

Please use colors in graphics that are easy to distinguish even with red green vision deficiency. Also if other colors might seem more fancy (like those green and orange that are too close together, especially when the graphic has a small size). Prefer clear contrast over style. And use yellow, too. Thank you, it would improve usability a lot. — Preceding unsigned comment added by 87.179.148.231 (talk) 05:18, 28 November 2015 (UTC)[reply]

Chroma Subsampling

This article does not have any information on the chroma subsampling (4:2:0, 4:2:2?) used the various modes. SolarWind

Article location

Who had the dumb idea to move ATSC to Advanced Television Systems Committee? Nobody will look it up or link it under that term and the acronym is still unambiguous. The only thing it does are unnecessary redirects and cumbersome links, where one of the key features of wikis is easy linking. Christoph Päper 14:23, 12 Mar 2005 (UTC)

I disagree. Almost all abbreviations have a disambiguation page. For consistency, ATSC should also retain the full name as its key. By the way, is this correct English: "Broadcasters who use ATSC and must retain an analog signal have to broadcast on two separate channels, as the ATSC system requires use of an entire six megahertz channel."User:Treeos 14:52, 30 Dec 2005 (UTC)

1080p60?

Any news on the ATSC and a 1080p60 standard? Jack Zhang 01:32, 8 April 2006 (UTC)[reply]

Certainly no plans for it that I've ever heard of, and I imagine it would work quite poorly given the bandwidth constraints and the fact that only mpeg-2 video is allowed. Snacky 04:04, 14 November 2006 (UTC)[reply]

Six channel limit?

Can anyone provide a quote from any standard that limits the number of DTV programs per frequency to 6? While I haven't searched the standards, I believe there is no such limitation, and I gather this was written by the same well-meaning but deluded person who wrote the "1 program per MHz" misinfo. Snacky 06:20, 27 May 2006 (UTC)[reply]

My understanding was a limit of either four or six. But I don't have access, at the moment, to the publications in which I read this—and it was in 1998. President Lethe 15:12, 27 May 2006 (UTC)[reply]

It's definitely not four. Was this publication an ATSC standard? Snacky 16:10, 27 May 2006 (UTC)[reply]

"Six channels" is a pragmatic limit based on the resultant subjective quality. There is no constraint by ATSC beyond that imposed by ISO/IEC 13818-1 (Table 2-18), which uses a 4-bit field in stream_id to identify the video stream number. Thus, sixteen channels are possible. algocu 12:41, 20 September 2006 (UTC)

It seems like you're right, and thanks for answering. Also, thanks for your recent improvements to the article! All I have to add is that, to be really, really pedantic, the limit of 16 video streams does not limit you to only 16 virtual channels. You can re-use the same streams across virtual channels however you like. This is quite pointless, but I've actually seen it done with audio. Snacky 00:45, 21 September 2006 (UTC)[reply]

The stream_id specifies the type of encoding, i.e. MPEG-1 vs. MPEG-2. There is effectively no absolute limit on the number of streams in ATSC itself, you have 1048575 possible VCT channels. In MPEG, you can use a number of PAT and PMT sections to achieve the number of programs you want. So the only absolute limit is your 8191 PIDs in an MPEG transport stream. If you take away overhead PIDs and assume one audio stream per program and with a shared static image video stream, you can still fit over 8000 channels. So the real limit would appear to be the number of minimum bitrate audio streams you could fit into 6Mhz with QAM-256 or 8-VSB encoding.

The minor_channel_number in the PSIP must be between 1 and 99 for service_type ATSC_Digital_Television and for Audio_Only = a maximum of 99 program multicasts. For service_type Data, the minor_channel_number must be between 1 and 999 = a maximum of 999 data multicasts. -Dawn McGatney 69.139.231.9 (talk) 09:51, 22 April 2008 (UTC)[reply]

PAL signal

Its not clear from the article whether an ATSC tuner can display a PAL signal. Can someone who knows this please update the article with this information. —The preceding unsigned comment was added by Gaashish (talk • contribs) .

Why would it? PAL's an analog standard. Snacky 04:06, 14 November 2006 (UTC)[reply]

Sorry, we're not all experts ;-) I'm certainly not an expert in this area. Therefore please clarify your answer: if I buy a LCD TV in the US, with ATSC/NTSC tuner, can I connect it to the cable in The Netherlands (PAL)? Sorry for my ignorance....

In theory an ATSC television can display any PAL compatible video (576i), but you'd probably have problems with reception. The NTSC analog half will display the black-n-white picture, but no color. And the ATSC digital half is not compatible with the European Digital Television standards. So there's really no point in trying it. - Theaveng 19:53, 26 September 2007 (UTC)[reply]

Newer US HDTV sets have both ATSC and NTSC tuners; neither can receive PAL broadcasts. -Dawn McGatney 69.139.231.9 (talk) 09:55, 22 April 2008 (UTC)[reply]

ATSC versus digital terrestrial

I don't see why ATSC is compared to digital-terrestrial standards such as DVB-T or ISDB-T at some points in the article instead of comparing ATSC to to the more general standards DVB and ISDB. --Abdull 14:53, 14 March 2007 (UTC)[reply]

Because ATSC is a terrestrial standard. - Theaveng 19:55, 26 September 2007 (UTC)[reply]

Earth-Moon-Earth?

Seems like original research; also, practical amateur radio systems cannot implement this and aren't likely to for decades. N8EVV aka Marc W. Abel 04:49, 28 June 2007 (UTC)[reply]

DT2

Is a DT2 channel part of ATSC? If so, is there an article that says what it is? Jim.henderson 02:34, 17 July 2007 (UTC)[reply]

Yes. DT2 is the 2nd digital service within a physical RF channel. It thus should be specified in the station's PSIP, which is described in ATSC A/65C. -Dawn McGatney 69.139.231.9 (talk) 10:17, 22 April 2008 (UTC)[reply]

Why doesn't ATSC work in moving vehicles?

The article does not explain, and I think it should explain WHY, rather than just say "it doesn't work". - Theaveng 19:57, 26 September 2007 (UTC)[reply]

Because of the need for an ATSC receiver to sample the transmitted signal at very precise times, the digital receiver cannot be in motion; motion would cause a slight change in the timing of the signal at the receiver due to the Doppler effect; this would make accurate sampling of an 8-VBS signal impossible. Enhanced 8-VBS or E8-VBS seeks to overcome this limitation by broadcasting a more robust signal at a lower data rate. -Dawn McGatney 69.139.231.9 (talk) 10:21, 22 April 2008 (UTC)[reply]

HDTV and SDTV

The article briefly touches on something interesting but doesn't explain it:

If ATSC were able to dynamically change its error correction modes, code rates, interleaver mode, and randomizer, the signal could be more robust even if the modulation itself did not change. It also lacks true hierarchical modulation, which allows the SDTV part of an HDTV signal to be received even in fringe areas where signal strength is low.

Is this implying that an SDTV stream is sent with every HDTV stream? What are the characteristics of such "SDTV" feeds? Are they just 7xx*480 4:3 rebroadcasts of the NTSC analog feed (or what would be the NTSC analog feed, if it were still being broadcast in 2009)? A number of TVs are being sold as ATSC SDTVs, are these using the SDTV stream or they just reformatting the digital signal, at whatever resolution it is, to fit a ~500 line NTSC screen? --Squiggleslash (talk) 14:31, 12 December 2007 (UTC)[reply]

E8-VBS allows a more robust, lower data rate signal to be simulcast with a higher data rate signal; if things are "bad", a properly configured E8-VSB receiver can switch to the more robust, lower data rate signal. In addition, the lower data rate signal can used by an E8-VSB receiver to "learn". -Dawn McGatney 69.139.231.9 (talk) 10:31, 22 April 2008 (UTC)[reply]

Dead(?) link

Inline footnote 1 simply goes to Businesswire's homepage, with a message saying "You must login or register before viewing this news release". 86.132.141.139 (talk) 20:12, 27 February 2008 (UTC)[reply]

Question about transition

Will the ATSC transition cause the FCC to allow FM radio station licenses on 87.5~87.9? Because there won't be any analogue TV audio from channel 6 on 87.7 after 2009, maybe that would be a good idea... --DaniAmaranth (talk) 12:28, 8 June 2008 (UTC)[reply]

Comparison (robust signal)

When originally added, this comment said that the ATSC transmission mode is a "robust waveform". The word "waveform" was later changed to "signal", but the real problem is in what exactly makes the ATSC waveform or signal robust. As mostly commonly implemented with 8VSB modulation, ATSC seems far from robust under various conditions when compared with the older analog NTSC standard, as well as other digital standards. Under ATSC (with 8VSB) a viewer can experience severe or complete picture loss under wet weather or only mildly windy conditions, when pictures from analog NTSC broadcasts experience only slight degradation. This statement needs justification, especially in light of comparison to older analog standards, which ought to be discussed. —Preceding unsigned comment added by 140.142.183.42 (talk) 04:31, 7 January 2009 (UTC)[reply]

Low power analog after June 17?

Will low power TV stations be permitted to continue analog broadcasts after June 17? 204.210.242.157 (talk) 01:00, 7 February 2009 (UTC)[reply]

Yes. Also class "A" and translators. -Dawn McGatney, 15 April 2009.

North Korea adopting ATSC?

Though I'm bemused by the mention of North Korea in the ATSC section, does anyone have a source for North Korea's propaganda station aimed at South Korea converting to that standard? --Daniel Blanchette 06:50, 15 November 2009 (UTC)[reply]

1080p60

The standard was amended in 2008 to include 1080p50 and 1080p60 signals. Someone please update the resolutions table accordingly from the amended specification. --188.123.237.4 (talk) 18:14, 26 April 2010 (UTC)[reply]

Section "TP"

That used to be about ".ts", a common extension. I question the validity of the references for ".tp". I question the removal (and replacement) of the ".ts" section. Why was that done? Who reviewed it?--134.130.183.101 (talk) 11:37, 16 December 2010 (UTC)[reply]

No-one has removed anything, this section was in fact added with this edit; I think it is redundant, since the heading of the Video section specifically mentions MPEG transport stream. --Dmitry _{(talk •contibs )} 20:41, 23 December 2010 (UTC)[reply]

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: page moved. Vegaswikian (talk) 06:01, 29 August 2011 (UTC)[reply]

ATSC (standards) → ATSC standards – No need for parentheses here. This article is about ATSC standards. Facts707 (talk) 01:00, 22 August 2011 (UTC)[reply]

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

History of ATSC section?

History of ATSC section needed? Like when ATSC signals were first broadcast etc. Gooolog (talk) 01:06, 16 February 2012 (UTC)[reply]

Citation not really needed for Zenith payoff sentence

I don't know the right way to modify the cite, but the MIT Tech article cited for the preceding sentence describing the MIT-Dolby bribery scheme also verifies that a proposal was made for Zenith to be bribed as well, for a possible discount off patent royalty payments. Just saying "Citation needed" seems to imply there is no source, but the linked article discusses this issue (in the article's continuation on page 15, not on page 1). — Preceding unsigned comment added by 184.5.200.69 (talk) 20:11, 24 June 2012 (UTC)[reply]

Error in "MPEG-2"

The following sentence seems to contain an error:

The ATSC specification also allows 1080p30 and 1080p24 MPEG-2 sequences, however they are not used in practice, because broadcasters want to be able to switch between 60 Hz (news, soap operas) and 24 Hz (prime-time) content without ending the MPEG-2 sequence.

Is it 60 Hz and 48 Hz content, or 30 Hz and 24 Hz content? Or should it be represented in fps instead of Hz? 60 and 24 doesn't make a whole lot of sense for MPEG-2. Also, the 60 would seem to conflict with the table earlier in the section, stating the values in Hz a 1080p stream can handle; 60 Hz is not one of those. —/Mendaliv/^2¢/_Δ's/ 17:05, 14 June 2013 (UTC)[reply]

We are talking about 24 and 30 fps progressive source formats - i.e. film stock (or digital movie camera for prime-time shows) - encompassed in a 60 fps interlaced format. As they say above, broadcasters prefer to convert 24 fps progressive source (big screen movies) to 1080i60 with telecine#2:3 pulldown technique (thus a reference to '60 Hz') vs. directly using the 1080p24 format in the transport stream and switch back to 1080i60 as necessary. And 30 fps progressive source (TV shows) is seamlessly encompassed by a standard 1080i60 transport stream using 1080sf30 (progressive segmented frame) technique. I rephrased the above sentence to include this explanation. --Dmitry _{(talk•contibs)} 08:30, 16 June 2013 (UTC)[reply]

Also, you should consider the paragraph preceding the quote above, which says that some TV stations actually use 1080p24 (or 1080p30) as the encoding format in their 1080i60 transport stream. --Dmitry _{(talk•contibs)} 08:40, 16 June 2013 (UTC)[reply]

Is Surinam ATSC or DVB?

According to the map Surinam is using the DVB standard and not the ATSC standard, yet this article mentions it as switching to the ATSC standard. So which is it actually switching to? Sion8 (talk) 05:35, 21 August 2015 (UTC)[reply]

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Dubious statement in "MPEG-2" section

The first paragraph in the MPEG-2 section states that the frame size (before display) is 1920x1088, rather than the displayed 1920x1080, because it has to be divisible by 16. But 1920x1080 _is_ divisible by 16. Is there a boo-boo somewhere?

BMJ-pdx (talk) 00:38, 12 May 2017 (UTC)[reply]

You're right that this wasn't phrased correctly. MPEG-2 requires divisibility by 16 to apply to the width and height separately, not to the product of width times height. 1920x1080 (i.e., 2073600) is divisible by 16, and so is 1920, but 1080 is not. 1080 divided by 16 is 67.5, so it is not divisible by 16, and that is why it is padded out to 1088. Mulligatawny (talk) 00:47, 12 May 2017 (UTC)[reply]

H.264/MPEG-4 AVC disputed accuracy

The paragraph and table following it immediately currently claims levels 3 and 3.2 are allowed, but level_idc in the source given only talks about 31, 40 and 42.

Part 2 says for level_idc: Values shall be as defined in Table 6.3 of ATSC A/72 Part 1. However, the last one is table 6.1 in the document. It hints that a value of 31 would be level 3.1, while 40 is level 4 and 42 level 4.2 respectively.

Where did the other numbers for levels come from? In example, is it accurate for 1280×720 to support level 3.2 in standard, while the document referenced only mentions 40 for it? 84.250.0.210 (talk) 20:17, 6 June 2017 (UTC)[reply]

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Statement in MPEG-2 subsection is clearly incorrect (by simple arithmetic)

It is claimed that the 1080- and 720-line formats have the same number of samples per second since "1980*1080*30 is equal to 1280*720*60." But this statement is clearly incorrect; a simple check shows that 1980*1080*30=64152000, whereas 1280*720*60=55296000. I don't know if there is simply a typo somewhere or if this concept is incorrect altogether. (Also note that the statement is still incorrect if 1980 is replaced by 1920.)

Last ATSC patents expired on 2024-09-16

Via web page about ATSC patents was at https://www.via-la.com/licensing-2/atsc/atsc-patent-list/ and is now removed (404 error).

Last patents document is still here https://www.via-la.com/wp-content/uploads/Final-July-1-2024-ATSC-Attachment-1.pdf and lists many patents all expiring on 2024-09-16.

ATSC 3.0 patent list still available here: https://www.via-la.com/licensing-2/atsc-3-0/atsc-3-0-patent-list/

Someone should update and rework Patent holders section. — Preceding unsigned comment added by PepitoSgazzebuti (talk • contribs) 09:45, 19 September 2024 (UTC)[reply]