How much bandwidth would iChat video take?

Discussion in 'iPhone' started by iansilv, May 28, 2009.

  1. iansilv macrumors 6502a

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    Jun 2, 2007
    #1
    ok- I keep hearing everyone say "ATT's network would collapse" and what not if iChat were enabled. But here is the thing- how much data bandwidth would it really take up?

    Right now, the 3g allows simultaneous data and voice. So we have the existing voice network handle the audio part of the ichat. Then we are just left with video:

    forget 30 fps- maybe 15 at most, probably more like 10- even if the network is perfect. So we have 10 fps on a screen with a resolution of 320 by 480- but the incoming video stream would not be that high- it would probably be displayed less than that- so lets say 200 wide by 150 high- ok so now we have 200 by 150 video at 15 fps. We are talking postage stamp video resolution of 1996 when real player first hit- but because its on a phone its way cool.

    Not to mention compression and hardware decoding will make the stream smaller.

    And- heck the resolution of the video being taken could be 2/3 that and interpolated up to that. Sure it would look like crap on a full screen chat on a mac desktop- but who cares? We would have working ichat video on a cell phone.

    Also- ichat for the mac would be updated to identify people on iphones and change the outgoing stream resolution and compression for them to accommodate their phones picking it up.

    thoughts anyone?
     
  2. Phil A. Moderator

    Phil A.

    Staff Member

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    Shropshire, UK
    #2
    Wirelessly posted (iPod touch 32GB: Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A312g Safari/528.16)

    Here in the uk, virtually every other 3g device supports video calling and itworks fine over standard (384k) 3g signals. I don't think it would be a massive strain to be honest.
     
  3. Kahnyl macrumors 68000

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    Feb 2, 2009
    #3
    I thought back when video calling was first introduced years ago that it was cool and futuristic. Then I used it and realized that true, useful video calling is still futuristic. It's just a gimmick at this point in that it sounds good in specs but doesn't provide any useful functionality. Even if Apple were able to give it great UI etc. they'd still have to deal with the limitations of 3G. The bandwidth just isn't available for anything more than a crappy stream that makes you wonder why you're bothering. I made about five video calls on my last non Apple device and they were all just to try it out and see if the bad experience last time was a fluke.
     
  4. SAG3194 macrumors 6502

    SAG3194

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    Jan 4, 2009
    #4
    Consider the fact that 6 million people have iPhones and will be iChat-ting. Say 1 million at least on 3G and the rest over Wi-Fi
     
  5. Phil A. Moderator

    Phil A.

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    #5
    I'd agree that the video quality is hardly HD, but wouldn't say it doesn't have any useful functionality: When my daughter was growing up, I spent a lot of time working away from home, and she couldn't care less that the video quality was less than perfect because when I called my wife with a video call, she could see her daddy before she went to bed. This was in the days before HSDPA so I can only think the quality would be better now.
     
  6. iansilv thread starter macrumors 6502a

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    Jun 2, 2007
    #6
    So would anyone here have any ideas on the actual data throughput required for the video calling feature?
     
  7. skubish macrumors 68030

    skubish

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    Location:
    Ann Arbor, Michigan
    #7
    Can't say because it depends on the camera (resolution, fps, etc.)
    Its safe to say it will require 1Mbps to get decent quality.

    Also another problem is I don't think ATT 3G is symmetrical. The download is faster than the upload.
     
  8. iansilv thread starter macrumors 6502a

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    Jun 2, 2007
    #8
    Ok- what about what I typed above - 150 by 200 at 10 fps
     
  9. Small White Car macrumors G4

    Small White Car

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    Aug 29, 2006
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    Washington DC
    #9
    Well, you can compress it to any data rate you want. I can stream you some really nice 30 fps video at 800 Kbps, and some 'pretty ok' stuff at 100 Kbps. Lower than that? Sure! It just depends on what you're happy with, visually. Given these specs, I'd guess lower than 100 is just fine.

    So the question isn't "what data rate?" but rather "what quality?"

    And that depends on the camera and the phone's processor speed. Since we can't play with the new phone yet, we can't answer that question.
     
  10. Small White Car macrumors G4

    Small White Car

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    Washington DC
    #10
    Ok, I made a sample clip from a captured CNBC clip.

    It's 1/2 iPhone resolution, so 240x160, it would play back stretched to 200%. It's 10 frames per secon and looks pretty good.

    It's just under 40 Kbps (including audio) so I'd say that's a safe number to assume. Is that workable? I don't know, but video-wise, that's what's possible.

    (I'd share the video but I don't think I have a way to do that from here.)
     
  11. Revelation78 macrumors 68000

    Revelation78

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    Dec 18, 2008
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    North Carolina
    #11
    The only reason we may not see it on the iPhone, AT&T hasn't figured out a way to make a profit off of it.
     

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