[mythtv] Filter documentation?

[Bruce Markey]

Andrew, is there any user documentation for filters? The
filters directory has a README for the filter API but I've
never seen and documentation for what filters are available,
when would the user want to use them, what they do, what
options (if any) do they take, and how to add and remove
filters. That sort of thing. Do you think you might be able
to rough out something that could be added to the HOWTO?

--  bjm