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Re: ABSN reversed playback behavior

From: Chris Lilley <chris@w3.org>
Date: Fri, 3 Mar 2017 15:32:31 -0500
To: public-audio@w3.org
Message-ID: <836d250c-5f36-082b-b2f8-a36b3fc3c9e0@w3.org>


On 2017-03-03 12:52, Joe Berkovitz wrote:
> If anyone knows how the Ableton Live or Native Instruments/Kontakt 
> samplers handle this, it would be useful.
>
Kontakt added reverse in Kontakt 2 (non-realtime), and improved it in 
Kontakt 5 [1]. It /can /do reversed  looping, but only in 'sampler' mode 
(which I think builds an in-memory buffer, possibly with loop unrolling) 
not in Direct From Disk (DFD) mode [2]. There are also some issues with 
setting the start point, having to calculate loop points in script based 
on the sample length [3,4], and not being able to re-tune samples 
because the offsets are in ms. There is also a 'rev' reversed instrument 
where the instruments are resampled backwards, presumably because 
reversed looping is harder to control and not as capable or performant 
as forward playing [5].

But it can do reverse loops.

I don't have Kontakt on my work laptop, but could check later if we need 
more details.

By the way when Joe was talking about attack portions followed by loops, 
it reminded me that reversed echo tails is a thing people do. IIRC that 
isn't typically followed by a looped portion of the sustained sound, though.

It would be great if our API could handle both use cases (the model Joe 
articulated and the one from Ray).

[1] "Time Machine Pro by zplane Development is the new Time-Stretching 
algorithm in Kontakt 5. TM Pro offers better real-time non-sliced 
stretching of melodic and tonal material, Real-Time Sample Reverse and a 
HQ Mode."
https://www.adsrsounds.com/kontakt-tutorials/new-features-in-kontakt-5/
[2] Kontakt 2 disabled reverse loop mode
https://www.kvraudio.com/forum/viewtopic.php?t=143430
[3] On reversing instruments in Kontakt
http://waveforms.fairlyconfusing.net/2016/01/on-reversing-instruments-in-kontakt.html
[4] Kontakt can't handle reversed loops properly.
https://www.native-instruments.com/forum/threads/kontakt-cant-handle-reversed-loops.112330/
[5] Free Reverse Loops Made with Rev
http://logic-pro-expert.com/logic-pro-blog/2014/09/28/free-reverse-loops-made-with-rev.html

-- 
Chris Lilley
@svgeesus
Technical Director @ W3C
W3C Strategy Team, Core Web Design
W3C Architecture & Technology Team, Core Web & Media
Received on Friday, 3 March 2017 20:32:43 UTC

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