🚀 go-pugleaf

Thomas Kinsman (thomas@acadia.Kodak.COM) wrote:
:     There is no set terminology.  However, some terms you  will  find  in  the
:     literature which span the ideas you are talking about are:
:     A.  LOSSLESS COMPRESSION
:         This communicates that no  information  is  lost.   Categories  within
:         lossless  compression  describe  the  methods used to achieve lossless
:         compression.
:     B.  LOSSY COMPRESSION.
:         Of course, this communicates that the information content is reduced.

One thing that is commonly forgotten is that /all/ digital coding of analog
information is "lossy."  This includes both visual and audible information.
It is a mistake to ignore the quantization step when considering the loss
in a compression system.

Some people have a strong emotional reaction to the term "lossy", as if
linear PCM is somehow "lossless." I guess it is a philisophical thing...
But it might help to keep in mind that in a real world of finite
bandwidths and bitrates, so-called "lossy" compressions can result in much
less loss of useful information than so-called "lossless" compressions.
16-bit audio compressed 4:1 with a "lossy compression" will likely sound
better than uncompressed 8-bit audio compressed 2:1 with a "lossless
compression." A 1536x1536 image compressed 18:1 with JPEG is likely to look
much better than a 512x512 image compressed 2:1 with an entropy coder.

I really wish that we would find better terms than "lossy" and "lossless"
compression, since I think they distort the issues involved and provoke
an irrational reaction in people who ought to know better.

		-Ed Hall
		edhall@rand.org