[time-nuts] HP E1938 Web Page

Magnus Danielson magnus at rubidium.dyndns.org
Tue Aug 28 21:36:11 EDT 2007


From: Hal Murray <hmurray at megapathdsl.net>
Subject: Re: [time-nuts] HP E1938 Web Page
Date: Tue, 28 Aug 2007 15:48:14 -0700
Message-ID: <20070828224815.ADB28BE2B at ip-64-139-1-69.sjc.megapath.net>

> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+magnus=rubidium.dyndns.org at febo.com RETRY
> 
> 
> > JPG can be set to be losless, it's supported by the standard, but I
> > agree   GIF or TIFF is better. 

Let's separate the JPEG standard from the baseline JPEG file format JFIF (known
as JPG or .jpg). The JFIF file-format selects a profile of the JPEG standard
also known as baseline JPEG. Baseline JPEG is not lossless. A number of nifty
features from the JPEG standard (such as the IBM entropy codec) is left out the
baseline format. TIFF (which is not one compression algorithm, but a format
supporting several algorithms) supports the full JPEG standard, but this is
rarely supported in real life.

> gif and png are (normally) lossless compression.  They are intended for 
> graphs and such that only use a few colors.
> 
> jpg and tiff are intended for pictures with zillions of colors.  jpg is 
> normally lossy and tiff is normally lossless.

... in real life. Then we have upcomming JPEG2000. Wavelet compression.

Cheers,
Magnus



More information about the time-nuts mailing list