Sneaky Apple: 16bit Picture compression

Discussion in 'iPhone' started by Dr. Cabrera, Sep 24, 2008.

  1. Dr. Cabrera macrumors 65816

    Joined:
    Aug 25, 2008
    Location:
    Los Angeles
    #1
    I've recently noticed a few things

    If you plug in your iPhone, take a look at the battery icon, notice how poor the gradient is on the glow of the battery, that definitely does not look like a 24 bit gradient.

    now try this

    take a look at this picture on your iPhone, and take a snapshot

    [​IMG]

    you should get an image that looks exactly like the original

    Now instead of a snapshot save the picture

    What you should get is a compressed picture when you save the image

    Looking through the color gradient it seems that the iPhone is compressing the picture from 24 bit-> 16 bit color

    Basically what apple is doing is compressing the picture so that there doesn't appear to be any slow down when you browse through your pictures ( i.e less cpu load)

    I find this annoying because any picture imported into the iPhone also goes through this compression :(

    Any thoughts, or ways to remove this annoying "feature"

    Update: Here's an example of what is happening ( for those not browsing on the iPhone) I tried to capture exactly what is happening to the color gradient as best I could

    Here is the normal image ( full gradient)

    [​IMG]

    Here is what the Iphone is doing ( notice the gradient has been reduced)
    [​IMG]
     
  2. Clete2 macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #2
    Interesting find. I hope there's a way to circumvent it. When you allow the picture to sit on the screen, does it look alright? (e.g. when you add your own pictures, do they look fine when you're not scrolling through them?)
     
  3. Dr. Cabrera thread starter macrumors 65816

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    Los Angeles
    #3
    could you refine your question


    i think what you are asking is if you add pictures will it look fine

    the answer is no

    when you "add" pictures to your iPhone they are "optimized" via iTunes before you can view them on your iPhone. It is the optimization that is downgrading the quality of the picture
     
  4. Clete2 macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
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    #4
    I see.

    What I meant was: You say that when you are scrolling through pictures that you can see that it's in 16-bit color (if I read your post correctly). I was asking that, if you stop scrolling and leave it on a single picture for a second or so, does it show the picture in 24-bit color? You answered the question for me.

    Is it a drastic difference? (my iPhone is out for delivery tomorrow)
     
  5. Dr. Cabrera thread starter macrumors 65816

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    #5
    Oh apologies for not clarifying

    It is compressed even when the picture is standing still

    I merely mentioned the scrolling example as a reason why apple would even want to compress the image quality. For example it would take a lot more CPU power to scroll through 24 bit images, then it would to scroll through 16 bit images.
     
  6. hierobryan macrumors 6502a

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    #6
    What is that water droplet thingy above the hair?
     
  7. benflick macrumors 68020

    benflick

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    Location:
    Cincinnati, Ohio
    #7
    I've noticed that when browsing through my camera roll, the pictures appear more pixelated at first, then clarify, and look much better. Maybe this is picture compression?
     
  8. Clete2 macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #8
    I see. Thanks for clearing that up (ehhh that could be a bad pun). Yeah, it would take more processing power for 24-bit images.
     
  9. Dr. Cabrera thread starter macrumors 65816

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    Aug 25, 2008
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    Los Angeles
    #9
    Actually that's a very common phenomenon, it's called image interlacing

    [​IMG]

    its a technology used to load pictures completely at a low resolution, as opposed to displaying half an image


    but that is not what i am referring to

    the FINAL image is still compressed, the only way to see this is with the steps I outlined in my first post

    I will try to take pictures/videos when i receive my camera.
     
  10. NT1440 macrumors G4

    NT1440

    Joined:
    May 18, 2008
    Location:
    Hartford, CT
    #10
    yea its been pissing me off greatly that with such a great zooming feature, apple has decided to downgrade the quality of the pictures.

    to be fair tho, is there somewhere that apple has claimed its pictures are 24 bit?
     
  11. Dr. Cabrera thread starter macrumors 65816

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    Aug 25, 2008
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    Los Angeles
    #11
    The thing is, it is capable of showing 24 bit images ( when you take a screengrab of any 24 picture). What i find annoying is that (except screengrabs) when saving images, or transferring images to your iPhone it will result in them being compressed :( :( :(
     
  12. NT1440 macrumors G4

    NT1440

    Joined:
    May 18, 2008
    Location:
    Hartford, CT
    #12
    That has been one of my very few frustrations with my ipod. It just doesnt make sense to me that with the great zooming feature, they make it so that one zoom in and your already pixelating. I just hope theyll do something eventually, but i really dont think they will seeing as its been that way since the very beginning.
     
  13. Dr. Cabrera thread starter macrumors 65816

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    Los Angeles
    #13
    seems more and more people are noticing this

    as a thread stated

    the pictures look fine in the browser

    but when saved into the photo album the quality of the picture gets reduced :(
     
  14. Van Wildonher macrumors 6502a

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    Apr 29, 2008

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