Re: [linux-audio-dev] jack_process and pitch-shifting

From: Olivier Guilyardi <ml@email-addr-hidden>
Date: Sat Apr 23 2005 - 13:23:09 EEST

Erik de Castro Lopo wrote:

>Last time I looked, libsoundtouch used linear interpolation for
>doing vary speed. Linear interpolation is evil. Here is a table
>from a talk I presented a the audio minconf attached the LCA.
>
>Linear interpolation is simply no damn good unless you are *positive*
>the maximum frequency in your source material is less that 0.06 of
>the sample rate. For any real world signal, this is simply not the
>case.
>
>
>
My guess was good, then, about libsamplerate providing better quality.

>Secondly, I think the pitch shifter in libsoundtouch works by doing
>time stretching first and then vary speed on top of that (someone
>please correct me if I am wrong). In this is the case, it might be
>possible to replace the second vary speed stage with the vary
>speed from libsamplerate.
>
>
Together with a Jackbeat user, we agreed that varying the speed is
enough. We don't need (lo-fi) pitch-shifting. I'll stick with libsamplerate.

By the way, thanks for your work !

--
  og
Received on Sat Apr 23 16:15:15 2005

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