Ubuntu Audio Pitch Shifting filter

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http://askubuntu.com – I'm currently developing a video player software which intended to be an embeedded player. I'm using Java with VLCJ library for the video player. What i'm looking is a way, something to transform the audio output to make the output sound as oldman or a kid (pitch shifting, i guess is the name). VLC have this when enabling time stretch, but the video play speed is affected (slower to get oldman sound, but fast-forward-alike to get kid voice effect. Is there any solutions for this? I don't find this feature on VLC(J), so i think what i need is the audio output of the ubuntu itself (Ubuntu 12.0 (HowTos)