An Audio Transcoder

I found a program named MediaCoder which could do resampleing(up sampling /
down sampling).
I have successfully transcoded an audio with 8000 sampling rate to 16000
sampling rate.
Such that this software should be helpful to our project.
However, before starting to code, a bad news is that this software lacks of
documents.
It should be considered if it worth your time, especially when you have
other easier ways.

There are some tries i have done which may do some help.
1. The homepage of the project is at
http://sourceforge.net/projects/mediacoder
2. The widows executive file could be downloaded from
http://prdownloads.sourceforge.net/mediacoder/MediaCoder-0.5.0-r2.zip?downlo
ad
(And there is only windows executable version. ><)
3. The source files could be downloaded from
http://prdownloads.sourceforge.net/mediacoder/mediacoder-0.5.0-src.zip?downl
oad
4. In the source directory "mccore\src", "CAACPlus::Open" could be found by
search the words "SampleRate" in file "audioencoders.cpp".
5. In the function described in 4., samplerate is set to item and be passed
to "waenc.open".
6. It could be found the waenc object is of "CWinampEnc" class in header
file "audioencoders.h".
By 6. it's easy to suppose winamp sdk/library is used,
7. The winamp sdk could be downloaded from
http://www.winamp.com/nsdn/winamp/sdk/,
and it is also no document found in a glance. But the developer's forum
may be somehow helpful.
http://forums.winamp.com/forumdisplay.php?s=3356ac570e40e53faab5f2563014a7de
&forumid=14

I stopped here, because I have no idea about how to trace this sdk.