ietf-822
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Allowable-Degradation-Percentage header

1992-04-15 14:43:50
Excerpts from ext.ietf-822: 15-Apr-92 Re: Implications of MIME fo..
Nathaniel Borenstein(_at_)thu (961*)

Excerpts from internet.ietf-822: 15-Apr-92 Re: Implications of MIME fo..
Guido van Rossum(_at_)cwi(_dot_)nl (1368)

Summary: CONVERSIONS THAT LOSE INFORMATION ARE A NO-NO FOR MTAS!

Guido is right on the general principles here, but I think the specifics
are more complicated.
[...]
Moreover, we already know that it is within the bounds of reasonableness
for MTAs to reject mail based on size.  Now, if someone sends me a GIF
image, and the MTA says its too big, I'd much rather get it as a
lower-quality JPEG image than not get it at all, at least in most cases.

This goes back to a discussion we had a year ago:  What is the sender's
intent?  Why is an image being sent?  Nathaniel is distinguishing
between two cases, one in which we want to transmit the general form of
the image (every pixel is not significant), and one in which we need the
exact image.  Similar cases can be imagined in the transmission of
formatted text documents; there are clearly cases in which every comma
and linebreak is important, and other cases in which they are not.

Clearly (:-) a new header is needed: 
"Allowable-Degradation-Percentage", that will enable the MTA to make
decisions about whether to attempt format conversion.

Bill