How to loop sample and make repeat point smooth?

[alebu]

Hello! I need to loop sample and to save it as WAV file. Is it possible with Audacity?
I also need to make loop point smooth. Maybe someone remember in Fast Tracker 2 there was
a possibility not only to specify loop points but also to modify sample around it for better
smoothing. For example lets say I have string sample and I want it to play endlesly. If I just
adjust loop points then it will sound bad in loop points. So some sort of auto smooth must be used here.
If there is no such functionality then maybe it is possible to develop? I am programmer and have good
knowledge of C/C++ programing, but I have no skills in audio programming, so experinced consultant
could be very useful.

[archiegood]

alebu, look at tyler tyler's August 17 posting in the Recording Techniques forum and the answers thereto.

[alebu]

Thanks, but that is not what I need. In Fast Tracker 2 and other sound editors it is called CROSSFADE.
As I see, there is nothing like this. There is actually some Cross Fade In and Out effects but
I didnt found documentation on it and cant get how they works. I have strong feeling, that it isnt what I need.