Best iTouch movie Resolution

Discussion in 'iPod touch' started by EricGo, Feb 22, 2008.

  1. EricGo macrumors newbie

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    Feb 22, 2008
    #1
    My first transcoding is slowly inching forward courtesy of Handbrake 0.92. I chose the iPod touch preset, and am confused why it is 480 x 272, rather than 480 X 320 to match the iTouch's native resolution. The source material is standard DVD at 720 X 480.

    Thanks !
     
  2. wizard macrumors 68040

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    #2
    That is a really good question. I'd suggest looking towards the handbrake web site or related forums.

    Dave
     
  3. TP-Eric macrumors member

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    #3
    Because it maintains the aspect ratio. 480x272 is 16:9 widescreen, which matches the 720x480 resolution, which is also 16:9 widescreen. 480x320 is 4:3 fullscreen. If you convert 720x480 to 480x320 then you'll either end up with a squished screen (everything will look tall and thin) or the sides will be cut off, depending on your conversion settings, because you're either compressing or cropping a 16:9 widescreen video to a 4:3 aspect.

    Don't listen to Steve when he calls the iPod Touch a "widescreen." It isn't.
     
  4. AlphaBob macrumors regular

    AlphaBob

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    #4
    FYI, Handbrake does a GREAT job on may disks, especially newer releases*. However it won't deal with copy protection schemes. See MacTheRipper (http://www.mactheripper.org/) for help with that.

    * Hollywood is anticipating the demise of the DVD format (changeover to BluRay HiDef). They figure they make more money by no longer paying the royalty to the protection companies on every disk they sell, than they lose by illegal copying. They are anticipating the all digital and encrypted source to screen methods like HDMI will provide much better protection in the future. Also they are moving to include pre-ripped copies for use on media players that support DRM.
     
  5. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #5
    This is just not true.

    First, for a few standard aspect ratios ...
    16x9 video is 1.777...:1
    16x10 video is 1.6:1
    4x3 video is 1.333...:1

    Now ... when you scale that to common resolutions what do you find?

    Older widescreen movies are traditionally 1.85:1, which is actually slightly wider than 16x9. Modern HD resolutions (720p and 1080p) are true 16:9.

    Now ... what about standard DVD resolution? It's 720x480, so you got that part right. The ratio, however, is a paltry 1.5:1. That's pretty close to 4x3, isn't it?

    The iPod touch screen, in video orientation, is 480x320. That scales, exactly, to 1.5:1 ... exactly the same as DV or DVD resolution. Interesting, eh?

    The problem is that very few movies, if any, use the native resolution of a DVD. That's why, even on widescreen TVs, you'll get bars on the top and bottom for most movies. Look at the Matrix movies (2.35:1, IIRC) and you'll understand the problem.

    The iPod's screen is perfectly proportioned to standard DVD resolution and, for the sake of arguement, is a pretty good compromise between "true" widescreen (16x9) and "true" full screen (4x3) ratios.
     
  6. Viremia macrumors regular

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    #6
    Handbrake usually works fine at decoding DRM'd DVDs, provided you aren't using the version for Windows. I haven't found any DVDs that it wouldn't handle...yet.
     
  7. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #7
    Pirates 3.
     
  8. CorTeX macrumors member

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  9. davidy macrumors 6502

    davidy

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    #9
    The program "AnyDVD" stays resident in the background on your computer and strips the copy protection from all DVDs without any action on your part.
     
  10. EricGo thread starter macrumors newbie

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    Feb 22, 2008
    #10
    Ahh, dawning understanding

    Chris Brightwell, your post explains a lot. Thanks. Most DVD's I have are 16:9, and occasionally I see a 3:2. If I am following you correctly, the 16:9's should be ripped to 480:272, and 3:2 to 480:320. These setting will scale the source material down to itouch size without changing the x-y ratios. The tradeoff will be unused iTouch screen with 16:9 content. Right ?
     
  11. darkblu macrumors regular

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    Jan 20, 2008
    #11
    well, i see a couple of problems with that argument, and they are that:
    1. DVD resolution was designed around TV standards from many decades ago, not cinematic standards, and people are watching a lot of cinematic material on their PMPs these days, ipod included.
    2. the piggyback approach for making DVD's more cinematic by making them anamorphic does not work on the ipod, so all those widescreen DVDs are made back into isomorphic when encoded for the ipod.

    i think that the iphone screen's form-factor and resolution have much more to do with the fact that it's a dual-orientation (portrait & landscape) device and with its PDA applications than with some DVD standards of yore.
     
  12. EricGo thread starter macrumors newbie

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    Feb 22, 2008
    #12
    Ana what ?

    Seems like we can make this pretty complicated .. not only do the source material and display screen resolution matter, but the storage (e.g. DVD) and lens used in filming play their parts to confuse the poor sod like me who just wants to watch movies on his iTouch.

    I came across this nice explanation of anamorphing, although I'll have to read it again (and maybe again) to get all of it. I *think* that the usually-ok approach is to choose to scale down to 480 horizontal, and 480 * (1/movie's aspect ratio) vertical.

    Comments ?
     
  13. davidy macrumors 6502

    davidy

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    #13

    If you're using Handbreak then, under "Show Presets" set the resolution to the "iPhone / iPod Touch" setting. This will automatically set the output to the largest size that will fit fully on the width of the iPod Touch's screen. This means that, depending of the aspect ratio going in, either the entire Touch screen will be filled, or there may be bands at the top and bottom, but at least the entire width will be filled and the entire content of the movie will be shown.

    If there are bands at the top and bottom, you can simply touch the expand button on the touch screen and it will expand to the full height of the screen. Of course, doing that will chop a bit off the right and left edges of the picture but the people, etc. won't be stretched or squished.

    If you try to manually input the settings you may end up with content removed from the sides of the picture, or a distorted picture with the wrong
     
  14. darkblu macrumors regular

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    Jan 20, 2008
    #14
    if space is not of utmost concern to you, you may want to encode in 640 columns ('ipod high-res' profile) as that makes those encodings watchable on a TV screen too. furthermore, some people report successful encoding at 720 columns, but i personally have not been able to reach more than 658 columns with handbrake. still, at least we know the x264 encoder is not hard-limited to 640.
     
  15. Mr. Eko macrumors member

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    Jan 21, 2008
    #15
    What does it mean on the back of the DVD when it says 'Enhanced fro 16x9 televisions'? When right above it states '2.35:1'?
     
  16. lauph macrumors regular

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    30 mins from Cupertino
    #16
    So what if the 16:9 is squished to 4:3 during the ripping process? The 4:3 ratio is the PIXEL ratio on the screen on the touch. But the PHYSICAL ratio is definitely not 4:3. Reason being the pixels are not squares. They are rectangles.

    When you play a squished 4:3 on the 4:3 touch screen, the PHYSICAL length of each pixel lengthens the image, or you can call it de-squish.

    Try it out and see for yourself.
     
  17. darkblu macrumors regular

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    Jan 20, 2008
    #17
    anamorphic.

    the original cinematic aspect ratio of the movie.

    * the resolution aspect ratio of the ipod touch is 3:2 (= 1.5)
    * the physical aspect ratio of the ipod touch is 75mm : 50mm (= 1.5) crudely measured

    so i'd say the pixel ratio of the ipod is fairly square-ish (= 1:1).
     
  18. mrgreen4242 macrumors 601

    mrgreen4242

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    Feb 10, 2004
    #18
    You've been corrected already, but I wanted to add that the term "widescreen" is just marketing talk. Most people associate widescreen with 16:9 TVs because that's the most common/likely things they are going to see in a store/their home. A widescreen computer monitor is 16:10, as mentioned, and even though it's not as wide as a 16:9 TV we still call it widescreen.

    Movie theaters usually have screens that are 2.35:1 - much wider than 16:9, as most movies are filmed that way. Movies that aren't can still be shown by marking off the sides of the screen with the curtains.

    The iPod touch/iPhone screen is 2:1. Wider than 4:3 but not as wide as 16:9. At first I was disappointed, like you, that it wasn't "actually widescreen", that is 16:9 or at least 16:10, but after using it I'm really happy they chose to use 2:1. It's right between HDTV widescreen and standard TV ratio (1.33:1, 1.5:1, 1.78:1) so you can zoom in on any content to fill the whole screen without cutting much off of it (typically within what is marked off as overscan space during production, so nothing important is in that space).

    As for the original question, there's two ways to determine what resolution to use. If you want to watch the movie letterboxed (black bars top and bottom) use 480x272 (or whatever the correct aspect ratio ends up being, 272 is right for 16:9 content). If you want to zoom the video in to fill the screen and have maximum detail, set the height to 320px and the width to whatever the autocalulated number is, based on aspect ration. Then when you zoom, the iPod will just slice the sides off.
     
  19. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #19
    I missed your reply earlier, so I apologize for the delay. :) I didn't double-check your math, but you've got the theory.

    I set Handbrake to use 480x* for widescreen content (preserving the aspect ratio while making use of the full width of the screen) and full screen content to *x320 (preserving the aspect ratio while making use of the full height of the screen).

    I toyed with the idea of encoding widescreen at *x320, instead, allowing me to double-tap to fill the screen without losing resolution, but I haven't done any testing to see if its worth the extra filesize.
     
  20. davidy macrumors 6502

    davidy

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    #20
    I've already posted this but maybe it's time to do it again as obviously few of you have bothered to read it.

    It doesn't matter what aspect ratio the iPod Touch screen is and it doesn't matter what aspect ratio the source material is. [if you're using Handbrake]

    Simply set the Presets to iPhone/iPod Touch and the program will automatically decode the DVD to fill the width of the iPod Touch screen. While you're watching the movie you can touch the expand button to make the display slightly bigger (taller) but cutting off some of the edge of the picture.

    [I'm in a bad mood today and just feel like yelling at someone. Thanks for being there]
     
  21. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #21
    Either that or you're dead wrong.

    :rolleyes:

    I was right. You're dead wrong.

    This probably works for wide-screen material, but it doesn't necessarily work well for full-screen material and the presets run like a dog on G4 machine (thanks, h.264!). Changing the preset to use a 2-pass encode, use a lower bitrate (I use 768 kb/s), and use a different encoder will increase encoding speeds, increase quality, and decrease file size.

    Presets are a good starting point, but modifying that preset to your personal tastes or situation will give a much better result every time.
     
  22. davidy macrumors 6502

    davidy

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    #22
    These are the aspect ratios we have to deal with.

    1.33:1 A standard television set; equivalent to 4:3.
    1.37:1 Referred to as the academy aspect ratio, standard for films shot before the mid-1950s.
    1.50:1 The iPod touch 3" x 2" screen
    1.66:1 A bit wider than a standard TV, but not by much.
    1.78:1 The dimensions of a widescreen television set; equivalent to 16:9.
    1.85:1 Popular aspect ratio for many movies.
    2.35: Another popular aspect ratio for movies.

    I have converted every one of these from DVDs to the iPod touch using the iPhone/iPod touch presets and in EVERY case, I get 100% of the original film filling the full 3" width of the iPod touch screen, with varying amounts of height to make up for the varying aspect ratios.

    If you want a bigger picture with less information then be my guest. If you have an aversion to black bars at the top and bottom then go ahead and enlarge the picture, but you WILL lose information on the sides.

    You say I'm wrong; I think you're wrong. I'll let it go at that and continue doing my conversions my way; you can do the same and anyone else reading this can make their own choice.
     
  23. EricGo thread starter macrumors newbie

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    Feb 22, 2008
    #23
    Chris,

    I can attest to encoding being slow with a G4 ! On my 1.67 Ghz Powerbook encoding h.264 with ACC audio is about 5 fps using the Handbrake preset. Would you mind giving more specifics on an alternate you use ?

    I'd also be very interested to hear what speeds people using Intel based macintosh notebooks are getting. My daughter is waiting for her MBA (already christened J Eyre), and it would be a nice to know that encoding for the house iPods required less planning ahead of time. Course, the home iPods have different screen resolutions, but I'm just going avoid dealing with that for now.
     
  24. Scarpad macrumors 68000

    Scarpad

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    #24
    If you're only interested in watching on the device 480x272, or 480x320 is the way to go, small file size native res. I encode with the Ipod High profile in HB, I use the Anamorphic option and Keep the AC3 and AAC, this give me a file rouchly around 1.75gb for a 2 hr movie, playable on my Touch, but still looks pretty good on my 46" LCD
     
  25. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #25
    I don't have my Powerbook in front of me, but there's a non-h.264 encoder (ffMpegX? I Don't remember! :() and that's what I use.

    I'll try to check tonight when I get home and let you know. It results in a dramatically faster encoding process.
     

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