[linux-audio-dev] How hard is it to write a pitch shifter?

Cournapeau David cournape at enst.fr
Wed Apr 7 08:46:44 UTC 2004


Erik de Castro Lopo wrote:

>>But I cant find out how to deal with the missing data that is removed - to
>>keep the original length. 
>>    
>>
>
>Changing the pitch without changing the length is true pitch shifting. The
>code and concepts required to do this well is extremely complicated.
>  
>
To do it well is difficult, but the basic stuff is really simple, if you 
have a library to do sample-rate conversion: doing the time scale 
compression/expansion
with the simplest method (overlapp add) is just a matter of buffering. 
It will sound awful, of course !

David




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