Hello! I am writing a C++ program that works with audio files. The program supposed to make fade in / out (linear and logarithmic). Seems not a hard program but I can not find the formular for the logarithmic fading. Also, for complete understanding, could you posiibly give me the information on how fading actually works (inside the file, what byte should I changed etc.) Thank you! P.S. I need open the file and process fading by reading the file (manualy), I can not use any functions or existing library.

I think that you don't need to change byte.
My idea is that you must change volume when start/stop playing wave file(with the simple for) ;)
Good Luck.

Quote: (inside the file, what byte should I changed etc.)

This indicates that you don't know how your data is represented in the file. You simply need to understand how the data in the file is layed out. Often times these files are compressed, so there is usually not a fixed byte position for the volume of a particular piece. you should read about the specifications of your file type so that you know how to uncompress the contents and operate on it.