720p ... not really HD is it?

Discussion in 'General TV Discussions Forum' started by StooMonster, Apr 28, 2004.

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  1. StooMonster

    StooMonster
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    Okay it's 50% more lines than 480p line NTSC, but 720p is 25% more lines of resolution than PAL's 576p.

    This is similar quality leap of 20% more line definition that PAL has over NTSC.

    Do people generally believe that PAL DVDs look much better than NTSC ones? Or can't you really tell much difference with 20% more line resolution?

    Which begs the question can you really tell the difference between PAL and 720p?

    Or is this barking up the wrong tree and no-one cares about film based content (movies, HQ US television) and it's in video based content (sports, news) where the 720 rows at 50/60Hz beats 240 or 288 rows at 50/60Hz.

    StooMonster
     
  2. loadsofleads

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    It's a bit like the "broadband" connection at about twice the speed of a 56k modem, a blatant rip off imho.
    Europe actually though 1920/1080i was too low quality which is one of the reasons we are now playing catch up when it comes to HD.
    As for DVD, 480 or 576, the storage capacity for DVD is the same !!
    So you get less lines with NTSC with marginally less compression or 576 lines with pal with added compression to accomodate the extra lines, same difference in the end, the only place Pal should be superior is in broadcasts, but Freeview and especially Sky squeeze the bandwidth until the pips squeak so even that is a compromise !!

    :mad: :mad: :mad: :mad:
     
  3. Rimmer

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    720p is HD, as is 1080i.

    PAL's resolution is 720 x 576. It's interlaced, so only half the vertical resolution is captured in each scan (288 lines).

    720p has a resolution of 1280 x 720. It's progressive, so the full vertical resolution is captured in each scan.

    1080i has a resolution of 1920 x 1080. It's interlaced, so only half the vertical resolution is captured in each scan (540 lines).

    There's a lot of debate about whether 720p or 1080i is better. The EBU offically recommends the 720p format, but Euro1080 has chosen the 1080i format, so it remains to be seen which format will be adopted in Europe (maybe both will). Most US networks seem to have chosen 1080i over 720p.

    If you want to watch movies or filmic TV shows 1080i is definitely better as it produces the full 1080p resolution, 5 times PAL resolution as opposed to 2.2 times PAL at 720p.
     
  4. StooMonster

    StooMonster
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    Did I say 1080i or 1080p is not HD? Nope!

    Did I mention in my post the difference between VIDEO (half vertical resolution, twice the fields of film content) and MOVIE (twice the resolution, half the fields of video content)? Yes I did!

    Thank you, but I know the resolutions of formats -- and that the likes of current generation of say Lumagen scalers can not process pixels in horizontal resolution and only vertical line count. :devil:

    US Networks chose 1080 because Congress told them too, and when Fox tried to do 720 they had their wrists slapped.

    No. A movie is 25 fps with 2:2 pulldown and is 576 lines of resolution per frame. A movie at 720p is still 25fps (or 24fps, won't go into that here) at 720 lines of resolution per frame.

    720 does not invent extra frames for movies.

    Therefore 720p movie is "only" 25% more vertical resolution than PAL 576p movie.

    I was pointing out that this is approximately the same quality difference as NTSC movie versus PAL movie...

    :rolleyes:

    Considering that most UK "56K modems" connect at an average speed of 33.6Kbs a 64Kb connection would probably be more ISDN than broadband. If people wanna pay for 128Kbs that's their choice.

    In reality the reason we are playing "catch up" is because we got so far ahead with SD television. How many 16:9 broadcasts do you see in USA, or Interactive Television services? Why are their stores still full of bit square televisions whilst UK has almost all television sold as "widescreen" ones (some 40% of all widescreen displays sold in Europe are in UK).

    The impact of getting so far ahead with SD is that digital broadcasters invested billions of pounds building platforms: from production through to distribution. And these platforms have an financial lifecycle: investment, breakeven, profit (at it's simpliest). The entire lifecycle must be complete for investors to get a good return on their money and make a profit. The digital broadcasters are not at that point yet, once they have recouped the investment they may think about switching to HD content -- but then only when mass market rather than a few hundred vocal enthusiasts are there.

    Furthermore, digital television and radio is more profitable if put to squeezing more channels into same bandwidth, and why Sky digital has hundreds of channels; hence the US government legislating that HD television had to happen, the companies involved did not do it through choice.


    To say that the only place PAL should be superior is in broadcasts is not necessarily correct, but can be seen large if you've ever spent any time and the USA and watched "television". With a 24" set you can see the scanlines from across the room at 20 paces it's so low resolution; broadcast analogue is much lower resolution than DVD.

    Point
    One can see why Americans think movies on 720p look so much better than 480p -- there's 50% more vertical resolution -- whereas PAL movie viewers won't notice so much difference as it's only about 25% more vertical resolution -- about the same difference as PAL has over NTSC.

    For PAL to really notice you need 1080 lines.

    StooMonster
     
  5. rcman2

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    I can't believe how wrong that statement is. No network was forced to chose any format. ABC chose 720p, NBC and CBS chose 1080i. Plus, This fall FOX will be in 720p. There is more than enough info out there about this.

    http://www.foxsports.com/content/view?contentId=2239194

    http://www.broadcastingcable.com/article/CA308210?display=Technology

    http://www.thomsongrassvalley.com/news/2004/20040129-sort97-FOX_Splicer_System.html
     
  6. meva

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    I've got a pal and an ntsc copy of the matrix and have never noticed any difference in sharpness/ resolution between the two.Yesterday I compared an (admittedly) ntsc copy of the two towers to a 720p clip of the same movie and the 720p looked a whole lot sharper.The recent 720p transport stream posting of TTT was something like 16 gigs whereas I think the dvd has approx 7.5 gigs of actual movie on it. I think maybe some of the potential resolution of a 576 pal dvd is thrown out to actually fit the movie on the dvd.
     
  7. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    You're having a laugh right Stoo?

    PAL Video tapes are the same 576 vertical resolution as your PAL DVD. Can you tell the difference between DVD and Video tape?

    Your post suggest that all 1080i sources are same quality and that all 720P sources are same quality. Upscaled 480i DVD can be 720P or even more......but does that mean it's same image quality of well compressed HD? No.

    It's what you put in the space you have that's important. I am sure you know that though which suggests you are trolling....in which case, good catch!:laugh:

    With regard to Lumagen scalers I am afraid you are incorrect. They process in both horizontal and vertical in current generation. The Sil and Big F de-interlacers limit to 720Horizontal of course which I guess is what you are talking about.

    Gordon
     
  8. digitalsafari

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    I think you missed the big plus point for 720p is it supports 60 progressive frames per second which is great for fast moving action.

    Jonathan.
     
  9. CKNA

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    Stoo is just trolling. Everybody has to rememeber that increased vertical resolution is just a part of better picture. Horizontal and temporal resolution are responsible for most of the detail. For example 1280 horizontal lines is a lot more than 720. Also 720p is pure progressive.

    Here are some numbers:
    Digital NTSC 720x480x30=10368000 pixels per every second.
    Digital PAL 720x576x25= 10368000 pixels per every second.

    As you can see they carry exactly the same amount of detail all the time.
    The reason why Germans (when working on inventing PAL) increased horizontal resolution is because they realized that with lower frame rate they had worse picture.

    As far as HD these are the numbers:
    720p60 is 1280x720x60=55296000 pixels
    720p50 is 1280x720x50=46080000 pixels
    As you can see 720p60 has 9216000 pixels more every second.

    The same goes for 1080i.
    1080i60 is 1920x1080x30=62208000 pixels
    1080i50 is 1920x1080x25=51840000 pixels
    Again 1080i60 has 10368000 more pixels than 1080i50.
     
  10. Muf

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    CKNA, you just beat me to it. To elaborate a bit, in the video world the term "lines of resolution" generally refers to horizontal resolution. The vertical resolution is fixed depending on the video standard (PAL, NTSC etc) whereas the horizontal res varies depending on the bandwidth of the various components along the path from camera to display.
    As I understand, horizontal res is defined as the maximum number of vertical black and white lines that can be displayed across the width of the screen without blending in to a uniform grey colour multiplied by 0.75. As far as I know the 0.75 factor is there to give a 1:1 representation of horiz and vert on a 4:3 picture, the figure would still hold true for a 16:9 picture since it is an anamorphic transmission. Here are some approximate values from memory
    VHS: 240 lines of resolution
    SD broadcast: 430 lines of resolution
    DVD: 540 lines of resolution
    Average TV set: 400 to 500 lines of resolution

    So, going by the same calculations 720p would have 960 lines of resolution. Add to this the extra vertical res plus progressive plus the superior colour sampling (no colour bleeding) and you get a very different picture.
    Putting all the figures aside, when a young child with no technical knowledge sea's it for the first time and says "Wow! how come it's so clear" then you know there is a difference.

    Jim
     
  11. Bob Todd

    Bob Todd
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    look all I know is I have seen the two towers in WM9 1289x768 which is hardly the best encode.

    Yet it rapes the rosebud of any official DVD release I have seen

    nuff said.

    .
     
  12. CKNA

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    Since HD is digital and uses square pixels there is no need to do anamorphic transmission. In digital there are no really lines of resolution. They are really pixels so in 720p every vertical line can have 1280 pixels. Normal broadcasts of 720p have about 1100 resolvable pixels per vertical line in US. It could be full 1280 but there are so many variables like processing plus some stations use filtering to lower compression artifacts if they simulcast so you loose some resolution. This is of course not any different from digital SD broadcast as you probably get 480 or less horizontal pixels due to filtering and overcompression.
     
  13. StooMonster

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    As I keep pointing out, MOVIES or FILM are still 24fps on SD or HD. 720p or 1080i still has 3:2 pulldown at 60Hz because it's only displaying 24fps, unless movie is displayed at 24fps (which HDTV standards can handle) :rolleyes:

    * MOVIES and FILM also includes almost all high quality US dramas because they are shot on film.

    Yes VIDEO content -- sports and news -- has 50/60 full frames a second, but MOVIES and FILM doesn't it has 25/24fps

    Anyone missed that main premise? Got any more, but it's 60Hz comments go to another thread. ;)

    Let's compare MOVIEs (which was my point) because that's what I watch on my AV kit, could not care less about seeing men playing with balls at 50/60Hz.

    Again remembering that 3:2/2:2 pulldown means that pixels are repeated, unless using 24fps display mode.

    480p ("NTSC") [email protected] = 8 mP/s (mega-pixels per second)
    576p ("PAL") [email protected] = 10 mP/s *20% more than NTSC

    720p [email protected] = 22 mP/s
    1080p [email protected] = 50 mP/s = now that's what I call HiDef, not this middle resolution.

    "Ah ha, it's twice as much detail" I hear you say, but this isn't really fair because SD are 4:3 ratios whereas HD are 16:9 ratios; so counting raw mega-pixels per second is not the right thing to do, not unless we normalise the comparison...

    4:3 720p [email protected] = 16.588 mP/s

    Which is less than twice the mP/s :devil:

    Most of that is made up with horizontal resolution, which isn't as visible to the eye as vertical resolution -- if this were not the case we wouldn't see widescreen displays of 1366x768 or 1280x768 or 1024x768, would they not all be 1366x768? Furthermore, Muf's table shows the difference between "SD broadcast" and "DVD" and most people don't notice the difference.

    So there could be case for arguing that removing this element from the comparison would be even fairer and one should just say:
    720 = 50% more vertical resolution than 480
    720 = 25% more vertical resolution than 576
    576 = 20% more vertical resolution than 480

    Hrm... 720 to PAL is like PAL to NTSC?

    Wrap me up
    In my view 720p is "okay" for movies -- no VIDEO content I want to watch -- but is not a huge leap of quality over SD 576; but 1920x1080, now that's what I call High Definition!

    Nuances
    CKNA's table reminded me of old arguments about Region1 vs Region2 DVD resolution, and R1-fanboys saying "but R1, it' just better isn't it; you can't see any difference for those extra 20% mega-pixels per second anyway".

    One wonders if those same people who couldn't see any difference with an extra 20% mP/s now evangelise about how much better 720p is?

    Give me 1080 anyday. :D

    StooMonster
     
  14. SweeJ

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    Hi, I'm a newbie and I've reading up alot on Progressive Scan and HD on various technical websites. However, I'm very confused about that statement above.

    Am I correct to say that HD NTSC in the US plays film/movies back at 24fps on HDTV then? I don't understand, is the 3:2 process still being done or not?

    How come then HD PAL will only play film/movies at 25fps and not 24fps?

    Please enlighten me, cheers!

    :confused:
     
  15. beeblebrox12

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    My first post here. Found this forum by mistake - very popular name ;) - but it looks like there's tons of interesting stuff here too.

    As for the discussions about the different HDTV standards - this topic has been beaten to death. Same as PAL vs. NTSC. I've often wondered why these discussions are so heated. I think it's because people argue over purely theoretical specifications and always judge quality based on the hardware that they personally own.

    The biggest factor in judging whether 1080i is better than 720p is the type of display you are looking at. Then what signal you receive and whether it is being converted. Third - what the original source material was. And last and least - the theoretical specifications of the standard.

    That being said on my 56'' Samsung 1280x720 rear projection DLP TV set being fed HDTV signal from a DVB-card equipped HTPC, ABC and the movie channels of my sat provider look amazing and almost always better than the 1080i channels used by most networks. On my neighbor's 57'' Sony rear projection CRT based (1080i native mode) set - neither the 1080i nor the 720p channels look as crisp as on my TV on well lit scenes, but CRT has its advantages in dark and fast motion scenes over DLP. And 1080i channels on his set are pretty much the same as 720p.
    Why is that? In theory for movie based material 1920x1080i should give you much higher quality than 1280x720p, because of the 24 fps nature of the film and with the 3:2 pulldown the interlaced display should effectively be displaying full 1080 frames most of the time?
    The answer is that CRT technology is just not capable of displaying the max 1920 horisontal resolution of the 1080i standard, and generally it is very difficult to even tune the tubes so that they display fully the two interlaced fields and achieve full 1080i vertical resolution. This results in effective resolution which is lower than that of a progressive scan 1280x720 digital display.
    Although interlaced CRT sets still beat any fixed pixel technology in blacks and lack of motion artifacts, they are on their way out and the future belongs to fixed pixel progressive.
    We need to add that companies using 1080i almost never use 1920, but limit horizontal resolution to 1440.

    Things might change with the mass adoption of 1080p displays, but for now 720p is not only a real HDTV, but also the better one if you have the current top-end plasmas, LCDs or DLPs.

    I also have all WMV9 HD-DVD releases by Microsoft and have to say that their 1280x720 material is the best picture I've seen at home.

    As for comparisons between PAL and 720p HDTV - that is just funny. Even theoretically 1280 times 720 is much more than 720 times 576, and the colour of HDTV is of much higher resolution. Practically that means that I personally find almost no difference between PAL and NTSC DVDs (I have only one PAL DVD though, so my experience might be inconclusive) and both standards look so poor both in definition and especially colours. They look almost like internet streaming video when I switch back to them from watching a good 720p HDTV movie.

    P.S. Forgot to add to the specifications argument one very important element - the effective bitrates. PAL and NTSC DVDs have the same bitrate - usually maxed out at 8 Mbps, while 720p and 1080i HDTV starts from 15-16 Mbps on sat and cable and is ususally higher off the air. So effectively, both HDTV standards have more than twice the bitrate of both SDTV standards.
     
  16. StooMonster

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    :oops:

    Of course I meant Fox's "Enhanced Digital" that they claimed was digital high definition television, when in fact it was 480p24 / 480i60 in 16:9 anamorphic.

    This is because Fox's business model was same as Sky digital: more channels of lower quality in same bandwidth equals more money than higher resolution channels. Hence why we have 500 channels of crap in UK. ;)

    It was only when FCC threatened to withdraw their licence that Fox relucantly agreed to transmit 720p, the shouting is now over (mostly) but search news stories around 2002 and you'll see plenty of discussion.

    StooMonster
     
  17. HD1080P4Ever

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    LOL, it has always been truth that 1080p is for idiots, fantasist's and losers. The genuine real difference between 720p and 1080p is so minuscule that said above waste extra money on 1080p. Throwing money in the bin is all the said above actually achieve (give them a round of applause).

    People with brains actually make the jump up to 2160p.

    1080p is a waste of space and time.
     
  18. Ian J

    Ian J
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    Whereas people without brains don't last long on this forum
     
  19. SyStemDeMoN

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    Nice work :thumbsup:
     
  20. MR2Harvey

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    I for one agree with the OP, 720P is not HD it's medium D, 1080i / p is proper HD. You do need a big screen to appricate it to it's full glory though!

    Funny thread this :rotfl:
     
  21. Yemeth

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    To prevent further necromancy, this thread is now closed.
     
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