ietf-822
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Re: MIME compression mechanism

1994-10-13 22:38:01
From: Keith Moore <moore(_at_)cs(_dot_)utk(_dot_)edu>
Subject: Re: MIME compression mechanism 
Date: Fri, 14 Oct 1994 01:06:32 -0400

I have read rfc1521 and draft-ietf-822ext-mime-imb-00.txt but I can't
find compression mechanism for MIME. As you know, picture or audio
data is too large. So, I think compression mechanism is very important
for MIME.

Both picture and audio data usually need a compression algorithm that is
fine-tuned for the type of data being compressed.  A general-purpose
compression algorithm (like gzip or lzw) is usually ineffective for these
kinds of data.

In these case, it is best if the content-type defines the compression.  For
instance, image/jpeg and image/gif images are already in compressed form. 
Audio/basic is also compressed (in a sense) by the use of mu-law encoding to
reduce the number of bits required by each sample.  One can suppose that
additional image, audio, and video types to be defined in the future will
also incorporate compression as part of the content-type itself.

Sorry, examples are wrong. My motivation is to compress text/plain,
message/rfc822, application/postscript, and application/octet-stream.

If current MIME has no compressin mechanism, I'd like to suggest a
subtype -- "compression" -- for Content-Transfer-Encoding:. For
example,

Such a mechanism might be useful for other types *besides* audio, video, and
image.  However, it would be difficult to gain support for a compressed
content-trasnfer-encoding, because a body part encoded with a unknown
encoding would be unreadable by every existing MIME reader.

Please discuss spec and implementation issue separately. All MIME
interfaces can't handle compressed MIME parts now. But when such a
spec is defined, many MIME interfaces would support this mechanism.

I'm implementing a MIME interface to Emacs(Mew). Many people ask me to
provide a compression feature. So, there is a great demand for this
mechanizm.

P.S.

Current version of Mew is avairable as follows;

--Kazu
<ftp://ftp.csce.kyushu-u.ac.jp/pub/Misc/mew/mew-current.tar.gz>
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