[please read] voice and amplitude

[Jay4795]

Hi, I'm using windows 7 and VS 2013 express. I am not a newbie to c++ btw. I Would like to make an application that allows you to input voice, extract the amplitude data at certain intervals and compare it to a pre-recorded file and do something based on if it compares. But I really do not want to just use a library for this, unless it is just for extracting the amplitude or something minor. I know it's not an easy task so please don't say just use a library or whatever. Where would I start on this please? (i.e what functions/library should I look at?) sorry if this was already posted but the ones I saw were too specific. Thanks for reading :)

[Smac89]

You say you are looking to not use a library, but you are asking what library you should look at?

https://ffmpeg.org/
The source code can be downloaded if that's that you are looking for