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RE: Adaptive images

From: Leonard Rosenthol <lrosenth@adobe.com>
Date: Wed, 1 Jun 2011 06:34:47 -0700
To: Simon Pieters <simonp@opera.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Maciej Stachowiak <mjs@apple.com>
CC: Henri Sivonen <hsivonen@iki.fi>, Karl Dubost <karld@opera.com>, "public-html@w3.org" <public-html@w3.org>
Message-ID: <D23D6B9E57D654429A9AB6918CACEAA98064C20F7D@NAMBX02.corp.adobe.com>
Doesn't have to be an "either/or".  If the author provides multi-resolution images (eg. JP2K) or progressive/interleaved AS WELL AS full alternatives, then you could achieve the best of both...

But yes, that's a LOT of burden on the author as well...

-----Original Message-----
From: Simon Pieters [mailto:simonp@opera.com] 
Sent: Wednesday, June 01, 2011 6:14 AM
To: Tab Atkins Jr.; Maciej Stachowiak; Leonard Rosenthol
Cc: Henri Sivonen; Karl Dubost; public-html@w3.org
Subject: Re: Adaptive images

On Wed, 01 Jun 2011 11:18:22 +0200, Leonard Rosenthol <lrosenth@adobe.com>

>> What about when the user zooms in on the image with an iPhone 3G?  
>> Wouldn't the user want the sharper image >then?
> Yes, you might indeed...
>>> I don't think any solution along the lines of "read from server and 
>>> stop early" cuts it either, because latency is high on modern 
>>> cellular networks in proportion to the bandwidth, so if I cut off 
>>> the server connection early, my incoming bandwidth has already been wasted.
>> Sure. On the other hand, if you need to load first a small image and 
>> then the large image when the user zooms in, >you will have wasted 
>> even more.
> True - but ONLY if the user zooms.  And you don't know ahead of time 
> if the user will do that :(.

Indeed. However, with the stop early approach you can stop with very low resolution for all images if the user starts in overview view, and then only load more when the user zooms into "normal" zoom view for images that are in view, which I would expect would save more bandwidth compared to author-supplied "normal res" and "high res" dual images.

Simon Pieters
Opera Software
Received on Wednesday, 1 June 2011 13:35:28 UTC

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