Re: [whatwg] Arithmetic coded JPEGs

[David Singer]

I think arithmetic coding is more problematic than you think, from a deployment 
and usage point of view.

Yes, it does save some bits, but alas minimum size is not what people optimize 
JPEG encoding for; they are much more interested in maximum compatibility. Much 
hardware support doesn’t include arithmetic coding, as far as I know, and even 
though libJPEG does, at least some users of that turn it off again.  I think 
that’s partly because it’s quite a bit slower in libJPEG.

So, one gains maybe 10-20% compression at the expense of compatibility and 
performance.  Not a trade-off people want to take, I fear.

sorry, practical realities bite again...

> On Nov 30, 2016, at 6:34 , Evgeny Vrublevsky  
> wrote:
> 
> Hello.
> 
> I'm writing about arithmetic coded JPEG support. Historically, it wasn't
> supported by browsers due patents. But all of these patents are expired
> several years ago, and modern libjpeg, libjpeg-turbo and mozjpeg have
> optional support of the arithmetic coding.
> 
> Arithmetic coded JPEG support will allow us to recompress all existing
> JPEGs losslessly, saving 10-20% of size. I've provided some examples here:
> https://bugs.chromium.org/p/chromium/issues/detail?id=669501#c3
> 
> Similar ticket exists also in the Mozilla's Bugzilla:
> https://bugzilla.mozilla.org/show_bug.cgi?id=680385#c17 . Now, I'm just
> following this direction from the ticket:
>> For now, the right place to go to move forward with this is on the
> standards mailing lists, not in this bug.
> 
> Unfortunately, browsers still don't support arithmetic JPEG officially. Is
> this a right place to start a discussion if it is possible to change it?
> 
> -- 
> Best regards, Evgeny

Dave Singer

sin...@mac.com



David Singer
Manager, Software Standards, Apple Inc.

Re: [whatwg] Arithmetic coded JPEGs

[Domenic Denicola]

Hi Evgeny, and welcome to the list!

From: whatwg [mailto:whatwg-boun...@lists.whatwg.org] On Behalf Of Evgeny 
Vrublevsky

> Unfortunately, browsers still don't support arithmetic JPEG officially. Is 
> this a right place to start a discussion if it is possible to change it?

This is a reasonable place to start such a discussion, in that browser vendors 
are often watching it and any of them that are interested will probably chime 
in with support. However, you've already filed issues on two browsers for 
discussion without much interest (as listed in your post), so it's not clear 
you'll see much more here, I'm sorry to say---browser bug trackers are often 
already the best way to reach browsers.

[whatwg] Arithmetic coded JPEGs

[Evgeny Vrublevsky]

Hello.

I'm writing about arithmetic coded JPEG support. Historically, it wasn't
supported by browsers due patents. But all of these patents are expired
several years ago, and modern libjpeg, libjpeg-turbo and mozjpeg have
optional support of the arithmetic coding.

Arithmetic coded JPEG support will allow us to recompress all existing
JPEGs losslessly, saving 10-20% of size. I've provided some examples here:
https://bugs.chromium.org/p/chromium/issues/detail?id=669501#c3

Similar ticket exists also in the Mozilla's Bugzilla:
https://bugzilla.mozilla.org/show_bug.cgi?id=680385#c17 . Now, I'm just
following this direction from the ticket:
> For now, the right place to go to move forward with this is on the
standards mailing lists, not in this bug.

Unfortunately, browsers still don't support arithmetic JPEG officially. Is
this a right place to start a discussion if it is possible to change it?

-- 
Best regards, Evgeny