Talk:1080i

message: Someone cares to add WHY the 0.03 fps difference exists; how it came about, and what the reason is of it's existence?
Thanks!  —Preceding unsigned comment added by 71.206.65.120 (talk) 04:03, 17 March 2009 (UTC)
replies: text: It came about with the move to NTSC colour.  It solved certain problems that existed had the frame rate remained at 30fps.20.133.0.13 (talk) 13:31, 27 October 2009 (UTC)

text: No it didn't. It was the introduction of colour that necessitated the slight change. Had the field rate remained at 60Hz, it gave a visible dot crawl pattern on the screen. Reducing the field rate by 0.1% to 59.94Hz solved the problem. By this time the accelerating voltages on the CRT were high enough that the slightly different mains frequency did no give a visible interference pattern because of stray magnetic fields. 86.162.147.159 (talk) 18:20, 5 October 2022 (UTC)
thread_title:  29,97fps vs 30fps? 

message: The terminology used within this article is deprecated. The preferred terminology as described by the ITU and SMPTE has the following format: xxxxy/zz where xxxx is the number of active lines per picture (usually 1080 or 720 when discussing high definition), y is the scanning mode (indicated by a letter i for interlaced scanning or a letter p for progressive scanning), next comes a slash character, and zz is the refresh rate of the picture. Thus standard definition television as used in Europe would be described as 576i/25. 82.127.93.74 17:40, 19 January 2007 (UTC)
thread_title:  Deprecated terminology 

message: When writing a paper you are not suppose to list references for someone who is reasonably skilled in the field would know already.  For example 1080i60 uses the same bandwidth 1080p30.  Most people who knowing something about video display know this is true.  A simple calculation of the image size times the frame rate shows this is true: 60*1920*540= 30*1920*1080.  So does wikipedia have a different standard for what should have a reference?  Daniel.Cardenas 04:25, 4 April 2007 (UTC)
replies: text: Since a paper on video display is intended for a particular audience, its author can reasonably make assumptions about what the audience should know.  Wikipedia, however, is aimed at a general audience, and we cannot assume that anyone reading the article is "reasonably skilled" in video display, or even that they know anything at all about video display.  Many, perhaps most, people reading this article would not know how to calculate bandwidth.  Fumblebruschi (talk) 21:00, 27 December 2007 (UTC)
thread_title: What to reference

message: I'm baffled. I thought 30 fps was the standard for US television, and that the difference between interlaced and progressive was whether the full frame was completed in one pass or in two passes. I'm no techie, so perhaps this could be explained in layman's terms. The discussion above compounds my confusion rather than ending it.
Second question, partly related to the first: Here's a quote from the article: "Due to interlacing 1080i has twice the frame-rate but half the resolution of a 1080p signal using the same bandwidth. This is especially useful in sport-shows and other shows with fast-moving action." I'm not sure what "this," the first word in the second sentence, refers to. It seems to me to refer to the subject of the first sentence, 1080i, which means that 1080i is better for shows with fast-moving subjects. I'm almost sure that's wrong, because of the movement of displayed objects in the picture between the first and second scans of the same frame. But even if it's not wrong, perhaps the pronoun "This" that begins the second sentence should be changed to a noun (The 1080i standard or the 1080p standard) to clear up any confusion.
: Many cameras doesn't use the same frame for generating the two frames in interlace. So what if you imagine 50 frames per second each divided in odd and even lines, you get the even lines of the first frame, then the odd lines of the second frame, then the even lines of the third frame, etc. This is also what makes de-interlacing so incredibly hard, because you can not just recombine the two frames to get the original. Carewolf 13:21, 2 August 2007 (UTC)
replies: text: Answer to "baffled". Interlaced (1080i) transmits 30 frames per second, ½ of each frame every 1/60th of a second. Progressive (720p) transmits 60 complete frames per second. On flat-screen HDTV sets (LCD or plasma), all broadcasts are displayed as progressive; thus the two parts of the 1080i frame must be combined (de-interlaced); some HDTV sets perform de-interlacing better than others. 1080p is not broadcast; it has twice the frame rate (60/second) of 1080i (30/sec). Many believe that 720p at 60 frames/sec is superior for fast-moving action (it's used by ESPN and ABC). -Dawn McGatney 69.139.231.9 (talk) 08:29, 30 March 2008 (UTC)
thread_title:  Layman's question 

message: The first paragraph speaks of frame rates of 25 and 30Hz for 1080i; yet the comparison table says 1080i is 50 or 60Hz and 1080p is 24, 25 or 30HZ. This appears to be a contradiction. —Preceding unsigned comment added by KX36 (talk • contribs) 06:15, 16 August 2007 
:This is not a contradiction; it's just from the standards that the Consumer Electronics Association have adopted.  1080i content exists only in 50 and 60 field per second varieties.  1080p exists in 24, 25 and 30 frames per second.  There is no analogous format for 1080i at 48 fields per second.  Traditionally, 1080p24 content will be telecinc'd to 1080i60 or sped up to 1080p25 and interlaced, making 1080i50.  — Preceding unsigned comment added by 206.248.184.215 (talk) 21:38, 22 September 2012 (UTC)
thread_title:  Contradiction in frame rates. 

message: Why does 540p redirect here, its clearly not the same. 83.108.208.28 (talk) 00:22, 9 July 2009 (UTC)
replies: text: Same question, almost a year later. Why does nobody fix things around here? --77.109.214.213 (talk) 11:19, 10 May 2010 (UTC)

text: Because 1080i is made up of two 540 interlaced fields. See Display resolution#Current standards. 74.179.40.22 (talk) 18:14, 18 May 2010 (UTC)
replies: text: One field is 1920 X 540. 540p is 960 X 540 pixels. Added to article to dodge further confusion. CadetMadet (talk) 01:04, 4 July 2010 (UTC)
replies: text: That information was deleted – along with various other material – about two months later (00:58, 28 August 2010 (UTC)
thread_title:  540p? 

message: Please fix my broken citation (#3, as of the time of writing). I could not find a way to link the image, which is on Wikimedia Commons, inside the reference. The image is the only real reliable reference, in this case (as explained in my edit comment). Comanoodle (talk) 21:02, 20 September 2009 (UTC)
thread_title:  Broken citation 

message: There is an edit done by an anonymous editor in the fourth paragraph: "1877x1000 (the actual displayed resolution of a 1920x1080 source) resolutions.", in contrast to the original "1920x1080 resolutions". Where in the world have they got that information? To my knowledge, all HDTV resolutions are displayed as such; no cropping is ever done (which I believe the author tries to say, in contrast to scaling). If nobody comments, I'll undo that. Elmo Allen (talk) 04:39, 23 November 2009 (UTC)
replies: text: Some televisions apply an artificial "overscan", were the outer 8-10% of the image wouldn't be seen, in the same way that older CRT displays tended to. However this is quite uncommon with modern displays.  —Preceding unsigned comment added by 121.98.240.135 (talk) 10:12, 27 April 2011 (UTC)
thread_title:  1877x1000? 

message: I think the article needs to be made clearer that interlaced video doesn't have to suffer any artefacts at all, and can produce the exact same results as 1080p broadcasts. The image used in the article is a bit misleading. For example, in the UK programmes are broadcast at 1080i for most HD channels, but the source material is 25fps, and so a 1080p television simply combines the two fields to produce an original progressive frame. You'd never under any circumstances see a combing effect, because the two fields are from the exact same original frame. As the article stands, it gives the impression that 1080i is always visually inferior to 1080p, which is nonsense. Teppic74 (talk) 12:15, 28 September 2011 (UTC)
replies: text: I agree with that, I think the image should be removed as it's misleading causing readers to think the combing problem is what interlaced video is supposed to look like, which is not the case.NJM2010 (talk) 12:25, 8 October 2011 (UTC)
thread_title:  Interlaced artefacts 

message: This article needs much more content!
It only discusses "perfect" content streams -- which is not the real world. What is the full bandwidth of a perfect 1080i stream? What is the real typical bandwidth of OTA broadcasts, cable broadcasts, and Bluray sources? How much of what kinds of compression is used, and how does this degrade various kinds of content? Signal encoding redundancy/error correction/artifacts?-96.237.4.73 (talk) 19:08, 14 February 2013 (UTC)
thread_title:  Bandwidth compression degradation 

message: sssss 202.165.91.8 (talk) 15:14, 26 May 2022 (UTC)
thread_title:  lkkkk 

message: Currently, there is a line at the bottom of the lead which says:
I have some issues with this. First, the source is Charles Poynton's personal website. In his words, he is "". There's no independent source, so we are relying on his statements alone. If the claim were more minor, and in his biography article, like "In the early 1990s, Poynton encouraged the use of 1080 lines and square pixels in HD video", I wouldn't have a problem with it. But this line goes beyond a minor claim about himself (WP:ABOUTSELF). It's a claim that he is the originator of 1080 lines (and therefore nobody before him proposed such a thing). That's a little too much to be backed up by his own website alone.
I also have some doubts about the veracity of the claim. According to "European Perspectives on HDTV Studio Production Standards", IEEE Transactions on Broadcasting, Vol. 35, No. 3, September 1989 (), Page 281 and 282 (elipses mine, bolded):
So, these authors (N. Wassiczek, G.T. Waters, D. Wood), had proposed square pixels and 1080 vertical lines as early as September 1989, earlier than "the early 1990s" from the line.
Here's another example. From Future Development of HDTV, CCIR Report BT.1217, page 180:
If you scroll up, you will see two diagrams also referencing 1920 samples and 1080 lines. I wasn't able to find CCIR 1986-90n itself, but judging from the name, I figure it came out between 1986 and 1990. That still seems too early for him to originate 1080 lines in "the early 1990s", especially since the CCIR 1990 conference ended on 1 June 1990. My speculation is that Mr. Poynton was one of multiple people to come up with the same numbers (by modifying NHK/Sony's de-facto standard, 1920 x 1035, to have square pixels). He certainly may have generated support for 1080 lines as a standard. But as it stands, there certainly aren't enough reliable sources to call him the originator/inventor of that number. 
HenryMP02 (talk) 03:58, 3 October 2022 (UTC)
replies: text: HenryMP02 – When questioning the authenticity of claims about science and technology, it's customary to assume good faith in the absence of evidence to the contrary. I’d be happy to talk with you about about the history of square sampling in HDTV, and clarify my contributions: +1 416 535 7187, any reasonable Toronto time. You may wish to review the 9-minute video at <https://poynton.ca/notes/misc/Poynton-square-pixels.html> for background. If I don’t hear from you in a week or two, I’ll post a summary here for the record. In brief, yes, I did it, and SMPTE recognized me for that work by awarding me the David Sarnoff Gold Medal in 1993. Cheers, – Charles  Cpoynton (talk) 20:39, 31 August 2023 (UTC)
thread_title:  Removing line about Charles Poynton 

message: The article incorrectly documented that the odd lines are stored in the first field and then the even lines are stored in the second. This is not correct, but to understand why requires a bit of history.
When interlaced analogue television was developed with the introduction of the 405-line system in 1936, the signal was transmitted as a sequence of odd and even fields. Which was first was technically unimportant, they just occurred odd-even-odd-even etc. etc. There was no difference other than timing changes. Just like a broken line in the middle of the road, the line follows the spaces which follow the line which follows the spaces etc. etc.
The specification for the 405-line system specified that the odd field occurred first in the complete video frame, but there was no technical reason why it should do so. It was purely a matter of convention. In fact (with one notable exception) all the specifications for all interlaced analogue video systems were written assuming the odd field came first."Characteristics of monochrome television systems (report ref 308-20 published by the Comité Consultatif International pour la Radio (CCIR, a forerunner of the International Telecommunication Union - ITU)) They could have specified even field with no change to anything. The one exception was the US National Television System Committee (NTSC). For some reason that is unlikely to become clear, although the makeup of the video signal was, more or less identical apart from timings, they decided to specify the even frame as being first. As already said, this made absolutely no difference - at least in the analogue world.
However, once digital video formats took off, it did make a difference. Digital video formats encode a complete frame as a distinct video unit (to facilitate compression among other reasons). Because they were originally created for NTSC standard signals, the digital video frame follows the NTSC standard and has the even field first. This survived into the DVD video format, and ultimately into the 1080i digital formats. This even first sequence was preserved when digital formats were copy-pasted for the 625-line analogue systems.
This created an awkward problem though it should not have done. Since 625-line video is specified as odd field first, someone decided that it was necessary to switch the field order to match the digital format's requirement meaning that it had to be switched back on replay (because the digital encoding switches the field order so that the even field which occurred after the odd timewise now comes first giving a time 'hiccup'). The article contains an image of what happens when the digital deinterlacing does not work well. The image could equally illustrate what happens when field order is switched incorrectly (actually a frequent problem with on-line video that was created with analogue systems and has been converted to non-interlaced digital video without switching the field order - the fields play out of sequence giving a similar comb effect). 
The unfortunate part was that this was all unnecessary because the digital encoding could have simply used the even field from the previous frame which would have completely obviated the issue.
 86.162.147.159 (talk) 17:03, 5 October 2022 (UTC)
thread_title:  Sequence of the fields