Talk:High-definition television/Archive 1

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Old talk from August 2001
Isn't 720p also a high-definition format? Also, we should add notes about the horizontal resolution, bandwidth requirements, and audio format.

HDTV is a subset of the DTV standards coordinated by the ATSC

See: http://www.atsc.org/press/PR_Def.html for more information about HDTV.

--Jonathan--

Fox HDTV program listing
According to the daily HD program listing on http://www.titantv.com, there is no HD program offered by Fox as of Dec 2003. Someone added Fox to the list which may or may not be valid.
 * Fox began HD network broadcasts in October 2004 --Blainster 08:04, 25 Feb 2005 (UTC)

Would like to read info & specs about about the audio signals used with HTDV broadcasts and how they compare to the audio of analog TV signals (specifically in North America). TIA!

this needs to be updated. HDTV is currently kicking ass, with almost all big budget prime time network shows broadcast in HD! Most major metropolitan stations are now broadcasting digital and reception is actually easier than analogTriptych

Comment^2 by adamgoldberg: Note that prior to the 2004-2005 television season, Fox was broadcasting in the resolution format known as 480p; as of the 2004-2005 season, they've converted to 720p. 480p is EDTV, not HDTV. 720p and 1080i are HDTV formats.

European MAC
analogue European MAC system update. Most of the information was taken from (http://murray.newcastle.edu.au/users/staff/eemf/ELEC351/SProjects/Jackson/hdtv.htm) (added to the external links).

TheWikipedian

pixels times lines ?
(1920 pixels × 1080 lines or 1280 pixels × 720 lines)

OR

(1920 columns x 1080 lines (2 073 600 pixels) or 1280 colums x 720 lines (921 600 pixels))

?

-- Answer --

I think if you are reffering to TV set resolutions you talk in lines and line pairs and if you are reffering to PC resolutions you talk in pixels. You shouldn't mix the two terminology because they mean different things.

Voom a cable company???

 * A cable company called Voom is currently the largest HD provider offering upwards of 40 High Definition channels.

I thought Voom is a satellite provider? I may be wrong though. Kowloonese 00:15, 14 Sep 2004 (UTC)


 * Voom is in fact a satellite broadcaster. They were owned by CableVision but with financial losses mounting while struggling to build a subscriber base, they have sold one satellite to Echostar (Dish network) and sold the rest of the company to a small investor group led by CableVision's Chairman.  --Blainster 08:11, 25 Feb 2005 (UTC)

Bit Depth
I would like to see a section on the bit depth of different HD TV standards. 1080i is capable of 8 and 10 bit's which effect the throughput needed to drive the signal.

Removed link
Unlinked Euro1080 since it was recursive (ie linked back to the HDTV article) Lee M 00:45, 7 Dec 2004 (UTC)

Old Japanese system incompatible?
As I understand it the original Japanese HDTV system used 1125 scan lines, which is equivalent to 1080i. Is that wrong? Lee M 00:45, 7 Dec 2004 (UTC)
 * I'd really like clarification on this point. If the original HDTV system is equivalent to 1080i then the statement that "Their old system is not compatible with the new digital standards" is false. Lee M 01:40, 26 Jan 2005 (UTC)

The old Japanese system is analog, not digital. The incompatibility is with the signal, not the lines. Gentaur 20:53, 22 December 2005 (UTC)
 * If I recall, because the Japanese HD system was analog, the 1125 number included "off screen" scan lines during the screen refresh. Only 1035i of those lines had picture data in them.  This is similar to NTSC having 525 lines, but only 480 of them actually have video information.  In digital video, the off screen lines are not counted, so NTSC is counted as 480i. Algr 04:29, 5 January 2006 (UTC)

And finally a gripe...
Despite being made in HDTV a lot of American shows are still being distributed to the UK in NTSC, resulting in a noticeable loss of quality. Are the distributors holding back the HD masters for the DVD releases? Lee M
 * And additionally I'd like to know whether Fox News and CNN International originate their European transmissions in NTSC or HD. Lee M 14:01, 29 Dec 2004 (UTC)
 * Cable networks in the United States are decidedly NTSC. No loss of quality from the original if it's already analogue. --Alexwcovington 14:33, 29 Dec 2004 (UTC)
 * Cable networks in US metropolitan areas have hybrid networks carrying both NTSC (analog) and QAM (digital) SD programming. Many have added HD programming in the last year, which requires changing the cable set top box (STB).  HDTVs are now beginning to  appear with CableCard slots which allow reception of cable programs without needing an STB.  And most all evening scripted primetime programming (that is,  excepting "reality" shows) is now produced and broadcast in HD.  I doubt if there is any "holding back" of HD content for any reason but licensing or transmission issues.  --Blainster 08:26, 25 Feb 2005 (UTC)
 * My cable company Interactive Optimum transmits content to the end-user in both QAM and NTSC. They push NTSC down on the CATV frequencies for analog users, and they also push many channels (including some that are also pushed down CATV) to digital boxes (QAM).  Also, they are acquiring more and more programming via MPEG-compressed feeds from satellites.  But many of these are still originated in NTSC standard, then converted for satellite uplink.  --Tonsofpcs 06:31, 11 August 2005 (UTC)
 * Don't you mean that the shows are being distributed in PAL? --User:Evice User talk:Evice Special:Contributions/Evice 23:10, 25 October 2005 (UTC)
 * No, I mean NTSC-M (RS-170a, 7.5 IRE Black). The United States of America is NTSC land. --tonsofpcs (Talk) 20:46, 30 December 2005 (UTC)

Interlace and frame rates
http://www.evansassoc.com/lib/Atsc-dtv.html seems to indicate that ATSC supports both 1920x1080 and 1280x720 at either 60 interlaced fields per second, 30 progressive frames per second or 24 progressive frames per second. That is, any combination of those. So for example film material could be broadcast at 1920x1080 at 24 fps. (But probably filtered a bit to make it fit in the available bandwidth.) Likewise, video material shot without interlace could be broadcast at 30 fps at the desired resolution.

Is this correct? If so, I think it should be clearly stated in the the article. At the moment the article only indicates that interlace isn't mandatory at 1920x1080. If 1080p is achieved by simply splitting each progressive frame into two fields then it matters whether there's metadata in the stream that indicates that it really is progressive video.

I suppose it would be up to the receiver to scandouble or -triple 24 or 30 fps to for example 60, 72 or 90 screen refreshes per second, if it's a CRT display. 60i is non-trivial to scandouble or display in a sane manner on flat screen monitor, of course.

ABostrom 01:18, 2004 Dec 20 (UTC)

http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html is a very informative article. It should be in the link section.

ABostrom 04:50, 2005 Jan 6 (UTC)

From article: "where the 1080i60 (or 50) signal can be deinterlaced by simple weaving of fields to frames, giving in effect a 1080p30 (or 25) image."

That's not really true. If you want to *broadcast* progressive 30 fps, then just broadcast 30 fps. That will however be interlaced when *displayed* on a *CRT* because few CRT:s will do 1080p60, it seems. But it is pointless and destructive to interlace the *broadcast* to 60 fps if the material is 30 fps progressive.

So it should say "A mix of interlaced and progressive scan is also encountered. At the highest resolution only 30 progressive frames or 60 interlaced fields per second are supported." or something along those lines...

ABostrom 05:24, 2005 Jan 6 (UTC)


 * I know that it is pointless, but I was told it was quite common in Australia.

Standardisation
"To limit the complexity of the technology some broadcasters in the United States have standardised on a single format for all broadcasts."


 * Is this the real reason? I hate the standardisation on a single format for all broadcasts from a single channel and the ignoring of the 1080p24/25/30 formats. I think it's stupid and wasteful, but they do it anyway and the article should be clear on why. Even the 720i50/60 formats may be useful sometimes. -- ABostrom 19:55, August 29, 2005 (UTC)

French analogue system
Shouldn't there be something here about the old French 819-line system? In modern parlance that would be equivalent to approximately 770i 25 4:3 b&w. Before the Japanese invented their system it was the highest definition analogue format, and in my opinion qualifies as HDTV. Lee M 01:40, 26 Jan 2005 (UTC)
 * Yes, and some people (including the BBC) saw PAL as the first High Definition Television broadcast, it was HD when it was made, but now it is SD. Think about it, when SVGA came out, it was High Resolution, higher than anything available.  Now it is standard, and no one really sees it as high resolution anymore.  --Tonsofpcs 20:17, 15 May 2005 (UTC)


 * So? If it's equivalent to 770i then it is better than 720i which is considered HDTV. So the old French system is HDTV. But 770i 4:3 is less than 770i 16:9, maybe less than 720i 16:9, so the original statement may be false anyway. And it's b&w, for crying out loud. :-) -- ABostrom 19:54, August 29, 2005 (UTC)
 * The British 401 line system was the first to call itself HDTV. There is no such thing as 720i, it's 720p.  Interlace at 50 hz can cost you as much as 40% of your real resolution so the french system had nowhere near the detail of 720p.  (I don't think 770i sounds realistic, it was probably more like 730i.)  Plus it wasn't widescreen and had correspondingly less horizontal resolution.  819 is history, not HDTV.

Video Resolution Image
The is wrong. VGA is 640x480; NTSC DV is 720x480 [0.9 pixels], NTSC D1 is 720x486 [0.9:1 pixels]; PAL DV and D1 are 720x576 [1.067:1 pixels]. Also, what are the lines inside of XGA for? --Tonsofpcs 20:14, 15 May 2005 (UTC)


 * The "lines inside" are to indicate that all HDTV material can be broadcast in a 4:3 as well as in a 16:9 aspect ratio. The lines show the width of the 4:3 content. --NicApicella 17/Jun/2005, 17:22 CET
 * 1024x768 is 4:3. XGA is not a TV resolution.  The numbers are still wrong.  --Tonsofpcs 08:20, 8 August 2005 (UTC)

Current/Future
Should BluRay be moved from "Future media" to "Recording and prerecorded media"? It is now expected to be on the market within a few months...
 * It should be moved after the products are introduced to the market. --Blainster 04:03, 12 Jun 2005 (UTC)
 * XD-Cam (Sony's 'Professional Disc') is a proprietary BluRay format and is on the market now. Also note that (for future) Panasonic's P2 is due to be released in September.  --Tonsofpcs 00:13, 13 Jun 2005 (UTC)

I would like to put a link to a Forum that has lots of discussion about LCD tv's. It would seem that if you are going to talk about the potential for HD, you would also want to discuss the current consumer products. Do something like that need approval? --Bryan8020 19:20, 9 June 2005
 * This article is about the HD format itself. Information on products using it would be more appropriate in the respective articles on those types of products.  --Blainster 04:03, 12 Jun 2005 (UTC)

Solid State Digital media is getting cheaper every month and will soon rival tape and DVD in cost per storage. It has the advantge of no moving parts and there are several cameras currently available that use this technology. It probabaly should be moved to "Recording and Prerecorded media" There is a JVC camera that records over four hours of HDTV on a DM card about the size of a stick of gum. --User: ProfChuck 21:00 27 Oct 2005

New category :High-definition television
I've created a new subcategory in category:Television. It's called High-definition television, and includes articles related to HDTV, such as HDMI, Dolby Digital, HDTV, ATSC... --Thewikipedian 13:08, 4 Jul 2005 (UTC+2)

Would it be better to have 2 versions of this article?
Quite a useful article for  me. But far too technical for someone who is looking for only non-technical information such as market penetration of HD etc. One can find the information by skimming over the technical info, but I wonder if it is feasible to have a non technical version as well or some other kind of device to differenciate between the techie and not techie elements.. that would allow for a much more readable article.

editdroid


 * It's better to fix the article. It was broken, I think I've made it better now, but please continue improving it. Anyway, there are country-specific HDTV articles (at least one US-specific) and technical standard specific articles (ATSC, DVB, MPEG-* etc.), articles about resolutions, frame rates, interlace, etc. etc. It's better to move information from this articles to those articles, if this article is too techincal. But what to movfe becomes more clear as this article improves. -- ABostrom 11:33, September 2, 2005 (UTC)


 * I am moving parts of the article (per country status) into separate wikis. Perhaps a separate country/area status report is better than just everything on a single page. I hope this will improve readability overalls. Thewikipedian 13:06, September 6, 2005 (UTC+2)

Codecs
Why do so many people ignore the fact that good old MPEG-4 Part 10 ASP (Also known as XviD, DivX, etc.) can compress HD video with much less resources required than ANY AVC codec, and at comparable bitrates and quality. Putting an in-loop de-blocking filter into the codec does NOT improve the quality at all, it just changes "noise which could be detail" into "no noise or detail".
 * First of all, DivX etc. are not MPEG-4 Part 10. MPEG-4 Pt. 10 is in fact H.264. otherwise known as MPEG-4 AVC. Second, there's a lot more to it than a de-blocking filter -- there's variable size blocks, a different block transform, and many other features making it a much better codec. Also -- the de-blocking filter doesn't eliminate detail (or noise for that matter) -- it reduces the perception of blocking by blending the edges of macroblocks.

Creating pictures
hi, are these pics usefull for the main article?

The last few images here contain mistakes - there is no such thing as 720i. (No one is broadcasting or making gear like this.) Algr 22:31, 2 March 2006 (UTC)

A good synopsis of the politics behind HDTV
Below is a link to one detailed and funny post on the politics behind HDTV. It can go a long way in enriching this article. I am sure I had seen it sometime in 2002, but never able to dig it out as slashdot search is very weak. 


 * I think that comment is wrong. Read instead. ABostrom 19:55, 24 October 2005 (UTC)

I don't understand.
"Moving images were thus blurred in a manner similar to using 16mm movie film for HDTV projection." What does this mean?
 * That is in reference to Multiple_sub-nyquist_sampling_Encoding --tonsofpcs (Talk) 20:34, 30 December 2005 (UTC)

Secam?
Both the introduction to this article and the television resolution graphic identify Secam as a standard definition standard. But the Secam section of this article refers to it as HDTV. Is Secam rightly identified as SDTV, or does it belong to some legacy set of HDTV?


 * The SECAM currently used is not the same as SECAM 755i -- ABostrom 19:48, 9 December 2005 (UTC)

Advantages of HD TV technology expressed in non-engineering terms
This section has several "Advantages" that have nothing to do with HDTV, so I'm pulling them out. (For example, plenty of low resolution sets can read memory sticks - and there is no conection between using 3 chips and becoming HD. The only such cameras for under $1000 are Panasonic's and they are NOT HD - the cheapest HD camera is a Sony one-chip.Algr 09:16, 24 January 2006 (UTC)

3D TV?
In the section Stereoscopic 3D television is far more practical with HD technology, it is not clear how HDTV would make 3D TV more practical. Based on the physics of stereoscopy, HD or not HD should not make a difference at all. This section does not make sense as is. Can someone expand on the topic to justify the section heading? Kowloonese 22:08, 13 February 2006 (UTC)


 * Well I can speculate that digital TV's support for multiple video tracks would make it much easier to transmit a separate image for each eye. Regular viewers could just watch one perfectly-normal channel, and not have to do anything special.  With data compression, you could also make the second channel share data with the first one, (Something like how P and B frames work.) so the second eye would need much less data, and both could run at near the resolution of a single HD image.  However I have not heard that anyone is actually _doing_ any of this - it just seems possible to me. Algr 22:47, 2 March 2006 (UTC)


 * May be so! But the article does not go into clear explanation.  While it is true that bandwidth allows the transmission of more video data required by the left right eye images, but the extra video signal is useless unless the display can present these images in two distinguishable ways so that the left and right eye would pick up the different images.  The Red/Green images filtered through Red/Green lens can selectively pass the two separate images to separate eyes, but the weird color gives the viewers a headache.  Recently the TV show Medium presented some black and white dream sequences in 3-D using the Red/Green images.  In my opinion, those Black and White images don't do justice to HDTV's vivid color capability, though the HD gives a sharp 3-D image.  Another approach is to use electronic shutter to block up alternating left and right images, that require special hardware that does not come with standard HDTV nor DVD players.  So I don't see how that is the reason why many 3D movies is going to be made available on HD-DVDs.  Like the Disney 3D technologies used in theaters, they change the polarization of the projected light so that the polarized 3D lens can be used to pick out one of the two images for each eye.  But regular HDTV has no such polarization capability.  So the bottom line is that the statement HDTV would make 3D TV more practical needs some backing.  I cannot see how anyone can make such a conclusion.  Did I miss some advanced HDTV feature that would explain that?  Kowloonese 23:42, 2 March 2006 (UTC)

information about hdtv AND 3D
Several years ago, the major US Networks held a public "3D experiment" based upon left-right eye perception differences of shades of gray v/s time. (Darker images get processed slower). You would wear a gray lens (20% ?) over one eye to watch, and some magic was done at the filming/editing/processing studio to produce a "3D" moving image. The process seems related to the derived 3D images captured by NASA from a single moving satellite. What ever else is done at the studio is a mystery. However, the human brain somehow perceives depth after the studio magic has been done. Without the dark lens, you wouldn't know it was there. The effect was lost in still shots. But for motion, I thought it was effective, and very cheap. No polarizing, red/green, or other switching technology was used, and the only down side was feeling silly wearing half a rayban.

HDTV, with it's greater range of light level resolution, might make the 3D effect more pronounced. Or, the converse might occur. Can anyone comment on this 3D technique and how it would interplay with the resolution power of HDTV?
 * That technique is far more of a gimmick then regular 3D. If your left eye is darkened, the camera must perpetually move to the right in order for the effect to work - either straight, or circling the action. The idea is that if you delay the image as seen by the left eye, the left eye will see the scene where the camera has been a fraction of a second earlier - which would be a few inches to the left of what the camera is seeing.  (There is no studio processing, you could do this with a home movie camera shooting out of a car window.)  But any other movement in the shot would cause the two eyes to see images that don't match.  My impression is that HDTV could expose more errors and mismatching between the two shots, and thus make the 3D effect less effective.  Or it might not make any difference one way or the other.  I doubt that HD would improve this.Algr 18:14, 13 March 2006 (UTC)


 * That is not new discovery. I remember I used to have a Laser Disc (those 12" platter) like more than 10 years ago on 3-D imagery .  The LD cames with all kind of 3-D glasses including the light-dark glasses you mentioned.  The 3-D effect shows in all panning shots in a certain direction. The panning does the trick, there is no need for special processing.  Kowloonese 22:11, 13 March 2006 (UTC)

Ads on external links
I think that the external links section redirects to a number of sites which appear to be custom designed for reporting Google ads and similar. Who is in charge of checking and (eventually) deciding to remove them? Cantalamessa 16:44, 7 March 2006 (UTC)