[ READ-ME - Sun Aug 16 10:00:35 1992 - multi-media MH for MH 6.7.2 - /mtr ]


				   NOTICE

     This package is openly available but is NOT in the public domain.
     You are allowed and encouraged to take this software and use it for
     any lawful purpose.  However, as a condition of use, you are required
     to "hold harmless" all contributors.

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     warranty.


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	NON-INFRINGEMENT.

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	INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
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Multi-media MH will soon be a part of the standard MH distribution
(Version 6.7.3 or later).  If you have an earlier release of MH, you
should either get a new release, or get the patches which are available
to bring your release up to MH version 6.7.3.

			  Using multi-media MH

Once your administrator has installed MH, you are ready to use it.  The
mhn program is the mhnproc, the progrma used to manipulate multi-media
messages.  You can write your own mhnproc, if you like.  In doing so,
just add an mhnproc: line in your .mh_profile which names your new program.

If for some reason you want to temporarily disable multi-media MH,
without editing your .mh_profile, set the environment variable
NOMHNPROC.  To re-enable it, unset this environment variable.

The mhn program knows how to do three things:

    - generate a table of contents for a multi-media message (-list),
    - display a multi-media message (-show), or,
    - store the contents of such a message in ``native'' (decoded)
      format (-store).

Here's the basics:  mhn knows very little about manipulating the actual
contents.  What it does, is look for entries in your .mh_profile telling
how to do things.  The manual entry for mhn(1) gives the full details.

So, the key thing to understand is where mhn gets its instructions.
First, mhn will look in your .mh_profile.  Second, if you have the
environment variable $MHN set, mhn will look in the file named by that
environment variable.  Third, mhn will look for the file mhn_defaults in
the MH library area.  The idea behind this is simple:

1. In your .mh_profile, you should have the definitions which are invariant
   when you invoke an MH program, e.g., default switch settings for mhn.

2. When you login to the system, depending on the kind of display you're
   using, you should set the MHN environment variable to point to a file
   containing definitions which are specific to that display.  For example,
   suppose there are two displays you use, both run X, but one has sound
   capabilities and the other doesn't.  You should have two files: both
   would tell mhn to use X commands like xv, but one of them would also
   tell mhn about the commands necessary for manipulating audio contents.

3. Finally, when the system administrator installed MH, a set of
   system-wide defaults werer created and put in the file mhn_defaults
   located in the MH library area.

In addition to manipulating multi-media messages which you've received,
mhn can also be used to compose them.  The current model is very simple,
you construct a "mhn composition file" and then run mhn as an editor
from the whatnow command.  The mhn program will interpret your
composition directives accordingly.  If all goes well, you can then send
the message.

If you want to split a large content into several messages, you can use
the viamail script.  The manual for entry for mhn has the details.
Also, if you want to split a large message into several messages, you
can use the new `-split' switch in send(1).

Finally, you should consult the manual entry for mhn and take a look in
the conf/multi-media/ directory for various examples.


			   What you can do to help

Once you have multi-media MH running well on your system, you should
look in the conf/multi-media/ directory to see if there's an template
for a system like yours.  If not, you should create such a template and
send it to:

	mh-users@ics.uci.edu

In particular, I'm interested in someone contributing a template for the
NeXT.

Send a note to

	mh-users-request@ics.uci.edu

to be added to the mh-users list, if you're not already on.
