Audio encoding help

Hi there, sorry if this is in the wrong section.

Im new to Ubuntu (and Linux) and have a problem, in windows I had some movies in the .avi container that was set at a frame rate of 23.976.

Now what i used to do was de-multiplex the audio re-encode the audio while time stretching it and then remux it back to the video at 25.000fps.

Now the only programme i can find that will time stretch the audio for me in Ubuntu is AviDemux but the problem their is that when it is done the audio sounds terrible, very static, and for the life of me i cant find an alternative.

So if anyone can find an alternative for me please I would be most grateful and if it is difficult set of commands a step by step how to would me most appreciated

try audacity, i believe it can to that.
but i wouldn't stretch it, just pitch it up or down, the minimal differences isn't really noticable.