[Flac-dev] question regarding compression %

[Gordon Gidluck]

Hi,
For those of you who don't know, I now have an application on pocket pc using flac. Live2496 does realtime encoding while recording. Live2496 typically is used to record a digital source using the Core Sound PDAudio device. Links are now on the main flac page if you are interested in learning more. 
 
I have a question. We have run across a 24-bit file that when we record it, flac level zero compression only results in about a 2% reduction in the file size. I use flac level zero because we don't have the computing power required for (higher level flac) realtime encoding on pocket pc's and windows CE. 

What is it about a file that would cause such a poor encoding rate?

A couple of observations:
Rectangular waves seem to encode at about 55-60% of the original size.
Muted digital sources seem to take up very little space.

Gordon Gidluck
http://www.gidluckmastering.com/live2496.html