Resolved 1080i v 1080p

Discussion in 'Apple TV and Home Theater' started by Macman45, Feb 8, 2012.

  1. Macman45, Feb 8, 2012
    Last edited: Feb 8, 2012

    Macman45 macrumors demi-god

    Macman45

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    #1
    I've been trying to work out which of these formats looks and performs the best. I know the "P" version is nominally accepted by the industry as being the best, but is not used due to the expense of the equipment involved.

    So, I have two HD TV's both will display both "I" and "P" formats. My Mac's also provide both options. I have tried both of them, and unless I'm missing something they look identical.

    Is there really a difference...? ( I shoot Video in HDMI 1080i ) Are there situations where the option of "P" is better?
     
  2. MovieCutter macrumors 68040

    MovieCutter

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    #3
    God that brings me back to the days of $1000 Blu Ray players...sheesh.
     
  3. maril1111 macrumors 68000

    maril1111

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  4. maturola macrumors 68040

    maturola

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    #5
    "p" is always better, but required more data to be transfer digitally, P stand for progressive while "i" stand for interchange. This mean that in progressive the image will load well "progressively", Line 1 then 2, then 3, then 4 and so on... "I" will load the odd lines first then the even line, your brain is able to capture the image "progressively" faster so for still images, that is not much of an issue, however for movies that have a lot of change on Color, contrasts and a lot fo movement it will defiantly make a huge diference.
     
  5. Macman45 thread starter macrumors demi-god

    Macman45

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    #6
    Read that, and a lot of bumpf too, but that wasn't my question. In certain situations (and as is covered in the first Googled article) there is supposed to be "A marked difference in performance"

    I've messed around with some "P" session DVD's sent to me by a friend in NZ and the only difference I can perceive is that the "P" footage appears slightly brighter.

    I don't think the standard will ever be adopted due to the cost of the equipment, but I saw no "Quantum Leap" in performance as has been described elsewhere.
     
  6. mstrze macrumors 68000

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    #7
    'i' stands for "interlaced", not 'interchange'.

    The loading of alternate lines of the picture are 'interlaced' together to form a full, moving image, one-half of an image at a time as opposed to the progressive display which loads and entire image with all scan lines each time:

    [​IMG]

    And yes, Macman45, 1080 p should be better, but if you don't see a difference, don't worry about it. If I were you, I would just set your HDTVs to always display 1080p...the connected devices will change the display if necessary, or the TV will convert the signal if needed.
     
  7. lostless macrumors 6502

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    #8
    1080P is 60FPS at full 1080. Each frame will be 1080 pixels vertically. 1080i is 30FPS, but interlaced. There is still 60FPS of information, but interlacing combs 2 fields (individual frames) into one frame. Essentially anything moving is only going to be half of 1080 in resolution. Anything standing still will appear to be the full 1080 as the 2 fields combine to make 1 full picture.

    For viewing purposes use 1080P as an output and 1080i may flicker a tad during still shots. Depends how good your TV deinterlaces and handles 1080i. But for the most part, from my experience, watching TV from the proper distance, they look the same.
     
  8. maturola macrumors 68040

    maturola

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    #9
    Again it will depend on the content, if you put side by side a recording of a sport event, you will see a "Quantum Leap" between them...
     
  9. Macman45 thread starter macrumors demi-god

    Macman45

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    #10
    Yep, formula one motor sport for example....The footage I have was taken with the new kit at last years (dubai?) race. Pin sharp, in fact so real looking the cars look like scale models, every detail is there.

    Do you foresee the adoption of the system on a wide scale in the future?
     
  10. maturola macrumors 68040

    maturola

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    #11
    Absolutely..no a doubt on my mind, specially with the TV and Monitors going to the new 21:9 ratio, it would be pretty much a "must" very shortly.
     
  11. fpnc macrumors 68000

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    #12
    The difference in quality between a progressive and interlace display setup will depend just as much (or perhaps more) on how the original scene was captured as it will on how it is displayed on your TV (i.e. the camera format versus the final display path). If it was originally captured in interlaced format it will probably look better played back on an interlaced display system than it would on a progressive system.

    Also, if the original was captured in progressive format then it may be difficult to tell the difference between a progressive and interlaced playback system (since, ideally, each full frame of the interlaced playback would look exactly like each of the progressive frames -- it would, in effect, appear as a progressive image that is displayed in a field-based manner).

    The comments about frame rates are also a bit misleading since in the U.S. only 720p broadcasts support actual 60 frame-per-second data (e.g. broadcast 1080HD is usually restricted to 60 fields-per-second interlaced, although 30 frames-per-second progressive is possible).

    Then, the situation becomes even more complex when you talk about the frame rate of the original progressive capture (was it 24p, 25p, 50p, or 60p). For example, progressive DVD playback of 24 frame-per-second, film-based material is output at 60 frames-per-second because you can quite easily use a 3:2 cadence to convert the 24 frames-per-second source to a 60 frame-per-second display format. Thus, for a DVD you simply repeat one of the progressive frames for three output frames, and then follow that with 2 repeats of the next frame which will create a 60 frame-per-second output from a 24 frame-per-second source.

    Think of it this way, two frames from the original film-based source represent 2/24ths of a second from the original capture (or 1/12th of a second). Now, if you repeat those two frames using the aforementioned 3:2 cadence you produce a 60 frame-per-second output that will occupy that same time period (i.e. 5/60ths or 1/12th of a second). This type of conversion was pretty much a requirement when TVs were using analog CRTs (which had a "natural" 60Hz time base) but now that we have digital-based LCD TVs the effective display rates can vary widely, all the way from a "true" 24 frames-per-second for film-based material to 120 or 240 frames per second which conveniently are integer multiples of both 24 and 30.

    So, to answer your question as to which will look better (1080i or 1080p) I'd say that it depends on a number of factors and YMMV and in some cases it doesn't even matter (when viewing under typical conditions).
     
  12. Macman45 thread starter macrumors demi-god

    Macman45

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    #13
    ^^

    Seems odd that we are now in the bizarre situation where (at least here in the UK) HD TV's have been able to display both formats for a number of years...The TV in my bedroom has got to be 4 years old, and it does both.

    Not one broadcaster in Britain uses the format due to the prohibitive cost of the equipment they would need to replace.

    The small amount of material I have was sent to me by a buddy in NZ..SO back home in the states, they are using it but only in 720? Hmm, looks like it's join to be a while before it's properly adopted.
     

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