Re: JPEG's libjpeg updated

From	pfraser <pete_fraser@comcast.net>
Newsgroups	comp.compression
Subject	Re: JPEG's libjpeg updated
Date	2012-11-17 09:25 -0800
Organization	A noiseless patient Spider
Message-ID	<k88han$fdj$1@dont-email.me> (permalink)
References	<k881fe$dcf$1@news2.informatik.uni-stuttgart.de> <k889ds$do$1@dont-email.me> <k88a90$fed$1@news2.informatik.uni-stuttgart.de>

Show all headers | View raw

Thomas Richter wrote:
> Am 17.11.2012 16:10, schrieb pfraser:
>> Thomas Richter wrote:
>>> Dear readers,
>>>
>>> please find a new version of the JPEG's libjpeg implementation
>>
>>> it supports [...] lossless coding,
>>
>> Is this LOCO stuff, or the old lossless JPEG, or something
>> else entirely?
>
> Yes, yes, and yes. (-:
>
> Ok, to be precise: libjpeg supports 10918-1 lossless, the old predictive
> lossless mode, as well as LOCO aka JPEG-LS aka 14495-1 plus a bit of
> 14495-2, and a new backwards compatible lossless mode. It also supports
> a hybrid lossless mode combining 10918-1 hierarchical coding plus
> 10918-1 predictive lossless (that's a bit "fake" since it requires a
> precise definition of the DCT process 10918-1 does not offer).
>
> The *new* lossless mode that is currently under standardization is
> backwards compatible to 10918-1 in the sense that the base layer is a
> 10918-1 compliant codestream every legacy decoder can decode. A decoder
> compliant to the new standard will get additional residual data that
> will allow lossless reconstruction if combined with the standard-defined
> fixpoint DCT and the standard-defined inverse multi-component
> decorrelation transformation (the I-FCT).

Thanks.
>
> The details are in the current working draft, which you also find in the
> repository (WD2.pdf). Sorry, the document is a very *early* draft, so it
> is partially inconsistent, and incomplete, and will likely change quite
> a bit over the next standardization meetings.

Yes. That's why I took the lazy route and asked you,
rather than poring over the original documents. I was worried that
I could spend hours, and still not understand.

Pete

Back to comp.compression | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

JPEG's libjpeg updated Thomas Richter <thor@math.tu-berlin.de> - 2012-11-17 13:55 +0100
  Re: JPEG's libjpeg updated pfraser <pete_fraser@comcast.net> - 2012-11-17 07:10 -0800
    Re: JPEG's libjpeg updated Thomas Richter <thor@math.tu-berlin.de> - 2012-11-17 16:25 +0100
      Re: JPEG's libjpeg updated pfraser <pete_fraser@comcast.net> - 2012-11-17 09:25 -0800

csiph-web