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A comment on Building a New Image Format. Parent comment

Re:Building a New Image Format by rplnt on Wednesday November 21, 2012 @10:19AM (#4814527)
Maybe it could be in a stream [headers][512px data][1024px data] and you could stop after the [512px data]. And since 512px image is a subset of 1024px one, you could do [headers][512px data][1024px\512px data] and so on.

(Just a guess.)

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Re:Building a New Image Format by spolster on Wednesday November 21, 2012 @11:59AM (#4815042)
You've basically just described interlacing. For instance, interlaced PNGs start with a 1/8 scale pass/frame and fill in the remaining pixels with the following 6. (Frames 1-5 would be required for a 1/2 scale image.)
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Re:Building a New Image Format by lobster_johnson on Wednesday November 21, 2012 @11:13AM (#4814778)
Unfortunately, because of buffering I believe this would still be inefficient. Also, it would screw up HTTP keepalive. A better way would be for the browser to fetch the header first by using the HTTP "Range" header, and then fetch the subrange it needs, but that adds one roundtrip just to get an image.
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