Questions about arts (mostly to be used in docs)

[tech at bishop.dhs.org]

You said to ask questions, so I'm taking you at your word :-) However,
I'm cc:ing kde-multimedia in case someone else knows, so as to make your
job easier...  

1)  I have the skeleton of a new PlayObject written, and I want to try
it out.  However, artsd keeps complaining about unknown file format when
I use artsplay on one of my test files.  I've compared my .mcopclass
file against various other ones, and I believe I have the format
correct.  Where should I be looking to debug this?  All applicable files
available upon request. I have both run kbuildsycoca by hand and logged
out/in.

2a)  Arts::Refiller has a method read that takes a pointer to an unsigned
char buffer.  I presume that you are meant to fill that with data from
your decoder?  If so, what format is it supposed to be in? I.e., 16-bit,
44Khz stereo little-endian?  How do you do stereo with one buffer?  I've
tried to figure this out by reading other PlayObject's code, but it
always seems to require either in-depth knowledge of (yet another) third 
party library (itc, for example), or the code is just unreadable.

2b)  The same method takes an argument of type 'unsigned long' (len).
What does that represent? The length of time/bytes/blocks/frames that
you should read into 2a's buffer? Something else entirely?  If it is a
length, how do you know what unit it is in?

3)  (probably should precede 2?) What is the bare minimum needed to
implement an Arts::PlayObject?  Should I be aggregating with ::Refiller,
something else, just plain PlayObject, ???  Am I correct in assuming
that a "Refiller" is "where the action is" (i.e., where you would
presumably instantiate a decoder object of your library, and do the
actual work)?  If not, what is the norm?

4)  Well, I need to go to bed, and that ought to be enough for one
night.  Thanks for any answers to this email, and I look forward to 
sending many more.  *grin*

D.A.Bishop