Licensing and public performance

[Andrew J Bromage]

G'day all.

I'm co-writing some software that is only really useful in a certain
media industry which doesn't have a history of being very "open" with
their source.  If it is used within the industry, it will very likely
be internally modified by media producers and used to produce works,
and the modified versions will almost certainly not be distributed.

I'd like to prevent this, but also, obviously, I'd prefer not to
trample on fair use.  I suspect that the answer lies in restricting
"public performance".  So let me ask the lawyers and non-lawyers:

Could I license a program so that if you distribute a work which was
created using a modified version of the software (which could be
considered as "public performance" of the software), you must
redistribute the modifications that you made?  And would it violate
the OSD?

Cheers,
Andrew Bromage