Sound Analysis/Editing in Android

I'd like to know how difficult it is to analyze and edit sound in android. My project would be a kind of DJ application.

I think AudioTrack is the most appropriate library, right ? How does the few android DJ apps 开发者_JS百科work to display the spectrum of the sound, apply effect, change the speed, mix ect ... Do they use a more powerful external sound library ?

For the performances issue, is Java fast enough ( or is there a risk of latency )?

And a last question : How does Korg ported its syth to Ipad, Wormux being ported to android, AngryBird works now on Iphone AND android ,ect ... all these apps seem to be ported to any platform without being re-written... how do they do ? It is because they are written in "Native Code" ? Should I consider this option so I can use other sound library ?

Thanks.

For purposes of editing sound or applying sound effects to a stream you can use class AudioTrack in conjuntion with one of AudioEffect subclasses of package android.media.audiofx, e.g. Equalizer etc ....
In order to analyse sound you should most probably apply FFT algorithms to the bytes you retrieve from class AudioRecord or some Reader.