[LAU] Sample Manager & Apps That Support Elastic Time?

Olivier Guilyardi ml at xung.org
Sat Jun 26 18:48:09 UTC 2010


On 06/26/2010 08:32 PM, Chris Cannam wrote:
> On Sat, Jun 26, 2010 at 4:03 PM, Olivier Guilyardi <ml at xung.org> wrote:
>> Rubberband is interesting, but when I had to develop a professional tool to time
>> stretch voice recordings, the quality was far from acceptable.
> 
> No, Rubber Band is better for some sorts of audio than others and
> speech certainly isn't its strong point.

Yep, that's right. I did a quite lot of tests, and realized every stretching lib
is better for some sort of sound than others. Also, some are optimized for
speed, not quality.

I've actually been happy with Rubberband for my own music stuff, but when I had
to develop a critical tool for mass stretching of voice recordings, Dirac just
did an incredible job.

As you may know, it seems to be the result of decades of developement by the
founder of Prosoniq, which also produced MPEX.

> Tim Goetze also had an example recently (here or on LAD) which it
> didn't handle well -- I've been looking into that one recently and
> hope to have some improvements there for the next release at least.

Also, when I mention Dirac support in Ardour, I don't mean that it should
replace Rubberband. In such apps as Nuendo and the like, the user has a choice
about which algorithm to use. Plus, since Dirac isn't FLOSS, it wouldn't be
installed by default in many cases I suppose. AFAIK, Rubberband and SoundTouch
are still the only free stretchers in the market place :)

But, from my tests, I believe that you could improve things a lot in regard to
voice processing.

I can recommend that you take almost any piece of voice, stretch in the 80%-120%
range, and compare the Dirac result with Rubberband's.

--
  Olivier




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