Talk:Standard-definition television

message: The pixel aspect ratios (PARs) listed for NTSC 720/480 and PAL 720/576 (8/9, 16/15 and their anamorphic counterparts, 64/45, 32/27) are incorrect.
They were all derrived from the assumption that the active display area, i.e. one of perfect aspect ratio 4/3 (16/9) is the entire 720*480 and 720*576 display, which is wrong. The actual active display area is
710.85 * 486  for NTSC
702    * 576  for PAL
or, taken approximately
704 * 480 for NTSC
704 * 576 for PAL
Therefore, the PAR of NTSC 720/480 is the same as of NTSC 704/480, i.e. 10/11 standardly and 40/33 anamorphically. Similarly the PAR of PAL 720/576 is the same as of PAL 704/576, i.e. 12/11 standardly and 40/33 anamorphically.
Unlike the 704-vertical-line (NTSC and PAL) display, for 720-vertical-line one the display aspect ratio (DAR) is no longer 4/3 (or 16/9). Indeed, it is
720/480 * 10/11 = 15/11 for standard "4/3" NTSC display
720/576 * 12/11 = 15/11 for standard "4/3" PAL display
720/480 * 40/33 = 20/11 for anamorphic "16/9" NTSC display
720/576 * 16/11 = 20/11 for anamorphic "16/9" PAL display
If we (very roughly) consider the standard display pixel as a E*E square, 
then the above approximated PAR still have an error of ~2*E on standard display and ~3*E on anamorphic display. There are better approximations which give error much less than 0.5*E, for example [1]:
PAR = 128/117 for PAL 720/576 and PAL 704/576
PAR = 72/79 or (even better) PAR = 4320/4739 for NTSC 720/480 and NTSC 704/480.
[1] Jukka Aho: A Quick Guide to Digital Video Resolution and Aspect Ratio Conversions. http://www.iki.fi/znark/video/conversion/  —Preceding unsigned comment added by 118.68.183.131 (talk) 15:44, 17 February 2008 (UTC)
replies: text: Actually PAL video is 702x576 and not 704x576, the PAR for 4:3 is 128/117 and for 16:9 is 1024/702.  77.113.93.250 (talk) 14:12, 26 October 2019 (UTC)
thread_title:  Incorrect Pixel Aspect Ratios 

message: In USA, SDTV refers to digital television broadcast in 4:3 aspect ratio, the same aspect ratio as NTSC signals. It has to do with the resolution, not the aspect ratio. The reference provided also does not support the claim - it doesn't define SDTV. SDTV is 480i, EDTV is 480p, and HDTV is 720p, 1080i or 1080p.--RLent (talk) 16:40, 30 April 2008 (UTC)
thread_title:  Definition of SDTV 

message: To my memory, when the BBC launched 625-line television, it was described as High Definition Television, it seems a little odd that this terminology can now be applied to the present as the old HDTV becomes SDTV and a new HDTV takes over - is there really any such thing as Standard or High Definition Television? The terminology is not used in other mediums - photographs/resolutions are mega/pixels. It is like saying the temperature is hot at 25c and the next day saying 26c is hot. I know there are the 1080 and 720 formats but why wasn't megapixels good enough for this? And I notice there is Extended Definition and Enhanced Definition available also. Seems anything to confuse the common folk is good for the industry. pebbens (talk) 01:29, 9 March 2008 (UTC)
replies: text: Even the original British 405 line system was called "high definition" when it was first transmitted in the 1930's.  Early experimental TV systems had as few as 12 lines.  For decades the term fell into disuse because all TV was in the same ballpark, so it was revived to describe the new 1000+ line systems. Algr (talk) 05:45, 22 May 2008 (UTC)
thread_title:  Standard Definition / High Definition 

message: The main page of this article leaves me wondering how many colors are possible from pixel to pixel in standard definition.   Am I right to assume that the color range is greater than can be resolved by the human eye?   Or is there some technical jargonese that explains which colors are possible, and how many colors there are?   216.99.198.124 (talk) 05:40, 12 May 2010 (UTC)
thread_title:  Color range for standard definition? 

message: Indeed there are.  SMPTE 259M does not state that program content should be scaled to 704 pixels wide, nor is it a 'mistake' for broadcasters to have program content in the entire 720 samples.  The difference between 720 and 704 is NOT for blanking.  There are 858 samples per line.  720 are for program content and 138 are for blanking.  Also refer to BT.601 for further details.  704x480 is ratiometric with the actual size of the active picture area of NTSC video, which is 710.85 samples wide by 485 lines tall.  Also, 704 is the closest modulo 16 size to 710.85. 
This article is poor enough it should be fixed by a subject matter expert (which I am not), or should be deleted and redirected. 146.115.66.42 (talk) 06:14, 26 May 2013 (UTC)
thread_title:  Glaring Inaccuracies 

message: "SDTV resolution by nation; [..] different countries use either 480i or 576i". E.g. the USA no longer broadcasts SDTV, right? Maybe wording under should reflect that, that this is only historical info. Any idea how non-mainstream SDTV is not and non-16:9? comp.arch (talk) 14:08, 20 March 2018 (UTC)
thread_title:  Time to change the map? 

message: I'm really not convinced by this section. The behaviour I have seen on TV equipment is a 720-wide picture uses the entire frame width (either 4:3 or 16:9), while 704 leaves 8 blank columns on either side of the image. Or more than 8 if you consider anything at the consumer level that can display images without overscan will almost certainly be an HD display, and therefore upscaled, but going there is making life complicated for no good reason.
While this article only covers television, I'd recommend any authors to experiment with VLC (or ffmpeg/Handbrake etc.) while playing DVDs, or any other sources where the intended resolution and pixel aspect ratio have been preserved. They will have a 16:15 aspect ratio for 4:3, and 64:45 for 16:9. Taking a square-pixels screenshot of a 720×576 movie results in 768×576 for 4:3, or 1024×576 for 16:9. If your source has been cropped to 704×576, it works out to approximately 750×576. Similar story with NTSC. I haven't seen any standard definition video which is expected to be played at wider-than-widescreen, as this article's table suggests, including, of course, live (Freeview) broadcasts. Attempting to play a 704×576 source at 4:3 (or 16:9) results in a slightly stretched image. Here for the one billionth edit (talk) 23:30, 27 January 2022 (UTC)
thread_title:  Pixel aspect ratio