MNG
Also in 1996 came the revival of efforts to produce a multiple-image variant of
PNG suitable for slide shows, animations, and very efficient storage of
certain simple kinds of images. Multi-image support had
been left out of the PNG specification for several reasons: multi-image
capability in GIF was supported by virtually no one; multi-image GIFs were
indistinguishable from single-image GIFs (i.e., they had the same filename
extension); including multi-image support in PNG would have delayed both
its development and its acceptance in the marketplace, due to the burden of
extra complexity, and creating a separate, PNG-based multi-image format
not only would be a logical extension of PNG but also would be more
appropriate to a group with backgrounds in animation and multimedia. As
it happened, however, this latter group never materialized, and with the
early-1996 release of Netscape Navigator 2.0 with support for GIF
animations,[54]
it became clear that the PNG Group needed to produce some sort of response.
Unfortunately there was a fairly fundamental disagreement within the group
over whether the new format should be a very thin layer on top of PNG,
capable of duplicating GIF animations but not much more, or whether it should
be a full-fledged multimedia format capable of synchronizing images, sound, and
possibly video. Although the former would have been trivial (and fast) to
design and implement, proponents of the latter design held sway during the
early discussions in the summer of 1996. In the end, however, something
of a compromise was created--though possibly due more to attrition than
consensus. Called Multiple-image Network Graphics, the MNG format design was largely
shaped by Glenn Randers-Pehrson and included simple but general operations
to manipulate sections of images, but no direct sound or video support. As
of November 1998 the MNG specification
was close to being frozen, but was also quite large and still awaiting
implementation in the form of a reference library similar to libpng. Until
such time as either a reference library or some other form of complete
implementation exists, the MNG spec will not be approved as a standard,
nor is it likely that more than a handful of third-party developers
will offer support for it.
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