Choosing the right template when writing a plugin

[Massimiliano Cialdi]

I have to write two audio plugins: the first is a simple processing 
block (some filtering), and the second is a decoder (something like mp3 
decoder)
In the plugin template 
(http://cgit.freedesktop.org/gstreamer/gst-template/commit/?id=afd75017e71129a200ca19ea68161f3526265e6a) 
there are 3 template to start from:
gstplugin.[ch], gsttransform.[ch] and gstaudiofilter.c.

I think that for my processing element I have to start from 
gstaudiofilter.c, but what about .h?

for the decoder element, which template should I use?

best regards

Max