W3C home > Mailing lists > Public > public-respimg@w3.org > October 2013

Re: JPEG 2000 (was: Multiple image files?)

From: Frédéric Kayser <f.kayser@free.fr>
Date: Fri, 18 Oct 2013 14:55:15 +0200
To: public-respimg@w3.org
Message-Id: <863F725B-E0F8-47C4-8357-AAF3B0551408@free.fr>
Hello,
I just wanted to share this is small excerpt from the introduction to JPEG 2000 in “Data Compression, The complete Reference” by David Salomon.

“One of the new, important approaches to compression introduced by JPEG 2000 is the “compress once, decompress many ways” paradigm. The JPEG 2000 encoder selects a maximum image quality Q and maximum resolution R, and it compresses an image using these parameters. The decoder can decompress the image at any image quality up to and including Q and at any resolution less than or equal R.
In general, the decoder can decompress the entire image in lower quality and/or lower resolution. It can also decompress parts of the image (regions of interest) at either maximum or lower quality and resolution. Even more, the decoder or an image server can extract parts of the compressed stream and assemble them to create a new compressed stream without having to do any decompression. Thus a lower-resolution and/or lower-quality image can be created without the decoder having to decompress anything. The advantages of this approach are (1) it saves time and space (2) it prevents the build of image noise, common in cases where an image is lossily compressed and decompressed several times.
JPEG 2000 also makes it possible to crop and transform the image. When an image is originally compressed, several regions of interest may be specified. The decoder or an image server can access the compressed data of any region and write it as a new compressed stream...”.

I'm not saying JPEG 2000 is the answer to all responsive images problems (it has its own drawbacks and it would require real image servers), but when you think about the possibilities and flexibility it offers…
JPEG 2000 has been adopted by the DICOM (Digital Imaging and Communication in Medicine) standard, the more I read about it, the more I think that the web has overlooked JPEG 2000 and it should perhaps get a second chance to correct this “historical error”. The JPEG committee was aware of the design flaws and weaknesses of the original JPEG, that's why they continued their work and proposed new standards: the lossless mode of the original JPEG has evolved in JPEG-LS, and then came JPEG 2000.
Why, oh why, are we stuck in the early 90's when it comes to image file formats on the web?

Regards
-- 
Frédéric Kayser

Johnna Nonboe wrote:

> Hi Eduardo,
> 
> You are absolutely right - I have pointed out this issue a long time ago in the forum. I know a lot of photographers with several thousansa of photos as well as many companies and private people who wouldn't use any time at all to convert their pictures into more sizes. Therefore the picture element is dead before it's even born. Only a few pro neerds (myself incl.) compared to the amount of pictures from 'ordinary' internet users will do the work as meant to.
> As I just wrote in another message: We need to use the interlaced pictures and let the browser decide how much to download for the actual screen. 
> A massive pressure on the browser companies might be nessesary - but then we must press them to make it happen ;-)
> 
> Johnna in Denmark
> (My English isn't perfect, either, but I guess you'll understand anyway).
Received on Friday, 18 October 2013 12:55:43 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:12:40 UTC