I need acelerate the sound, change your speed. For this, I’m using pitch code, that i found in GitHub… Ok, it’s possible, but, when the sound acelerate, it becomes more acute, and it’s my problem… I need change the speed, but keeping your característics… Someone could give me some tip about this?
Thanks…

I'm guessing you want to time stretch audio without changing its pitch? This is a very non-trivial signal processing task. Some (expensive) DAW software can do this for you, and there are some paid plugins to do this (e.g. IRCAM's one sounds pretty good, the product of >15 years of research). I wouldn't recommend trying to implement time stretching algorithms yourself, I'm an audio DSP expert and spent 3 months on mine and it still doesn't sound as good as the IRCAM time stretcher.