Re: CALL for DISCUSSION: eXIf 20170115

Willem van Schaik <[email protected]>
Newsgroups gmane.comp.graphics.png.general
Message-ID <[email protected]>
Having as many chunks as possible compressed is so because that was 
important 20 years ago. We were then competing with GIF on who had the 
smallest files.

Today when people are streaming video's of 100's of megabytes (or giga) 
saving a few kilobytes is not really relevant anymore.

And PNG with EXIF will mainly be used to replace RAW. Which are anyway 
files of many megabytes.

The reason that Glenn decided to stop pushing compressed was after I did 
some research on 1000+ random PNG images. Roughly 25-30% contained a 
tEXt chunk, around 10% had iTXt chunks and literally zero contained a 
zTXt chunk.

So if we add both compressed and uncompressed into the spec, in all 
likelihood nobody will ever use it. But on the other hand, every decoder 
of PNG with EXIF will have to (!!) implement both options.

I implemented my pngexif software (it inserts and extracts EXIF data 
into/from PNG files) without the need for any libraries. That's I think 
a big bonus. KISS :-)

Willem




On 2017-01-23 00:32, Cosmin Truta wrote:
>
> The work that we're doing right here is in direct competition with
> TIFF, which, for now, is the well-established, industry-standard image
> format. Every piece of PNG metadata of non-trivial size (if
> compressible) has built-in compression by design, and I would really
> appreciate understanding the reason why we are now giving up this
> practice and competitive advantage.
>

-- 
Willem van Schaik
[email protected]

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