For our group, we usually went for non-xp or level related rewards. Usually, we tried to keep them related to the real-life activity.

We were playing in a magic rich campaign, so if these rewards seem high, remember these items were relatively common (though expensive) in our world:


The player giving rides to everyone would find himself with a fairly regular supply of short-lived (they'd expire after limited in-game time) Haste potions, to do with as he pleased. 
The cartographer would get a choice of one of several items per session, such as find-item scrolls, detect magic wands. Since he put in a lot of work and proved useful to the party, the rewards both scaled up, and were often augmented by in-game tips from other players (the highest reward were single use teleportation items)
Snack providers would get bonus healing potions


etc... As a DM, I particularly liked that the rewards:


didn't mess up my planned levelling-up curve
fit in with the game-play
it was fairly easy to account for the rewards
usually it was items the players would try and stock up on anyways
since they were all consumable, usually with an expiration date, the players were encouraged to deplete their own supplies regularly.


In-game rewards for game-related work?
I wish to create a finite impulse response filter to decode a dolby digital matrix encoded 2 channel signal into 5 channels. These filters would then be used in a realtime pipeline on a Linux machine using jack and jconvolver to do the convolution.

The equation is as follows:

 

The reference for the above equation is: http://en.wikipedia.org/wiki/Matrix_decoder

It would seem this should be able to be done but I haven't the faintest how. Any help, and in particular working code that could generate the filters (Octave or other open source preferred) would be much appreciated!
