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Destructive vs. nondestructive editing

Subject: Destructive vs. nondestructive editing
From: Aaron Ximm <>
Date: Mon, 30 Jun 2003 13:50:49 -0700 (PDT)
A small note here, since concern has been raised over (a) potentially
detrimental rounding errors in [repeated] volume adjustments to digital
files, and (b) potential recovery to the original state as Evert
describes seems desirable.

My comment is that a mature contemporary editing environment should to a
significant degree answer these concerns.

Samplitude, the (Windows-only) editor I use, by default performs all
manipulations in its multitrack editing window as 'virtual' or 'realtime'
edits, rather than 'destructive' edits.

In other words, it creates a list of changes to be applied to a soundclip
(normalization, fade in/out, in/out points, EQ, gating...) and those
changes are calculated on playback, rather than written into the source
clip.  Ie, the file is normalized (etc.) on the fly, not on disk.

Of course to do this, it must maintain and save its 'virtual' settings in
a wrapper file (very small!), but the advantage is that the original
recording remains forever untouched.

A genuine advantage of this approach is that as long as your edits are
limited to the 'virtual' domain and not 'committed' as I describe below,
there is no generation problem ~ multiple normalizations/volume changes
collapse into a single one, performed 'on the fly' on playback.

(Incidentally, the 'realtime' calculations are no doubt cached away when
you're actually working ~ I certainly notice no perceptible decrease in
performance when manipulating virtually edited files.)

Of course, the edited version can at any time be 'bounced' down ~ written
out to disk as a flat, normal WAV (or AIFF etc.) file.

In fact, the latest versions of Samplitude let you both automatically
substitute into your multi-track composition the newly bounced file [the
original btw is not overwritten unless you want it to be!], -or-, as of v7
of the software, 'freeze' a version of your clip incorporating all of your
the edits -- explicitly write and use a bounced version out to save
processing if you're using expensive effects -- but with the caveat that
you can 'unfreeze' and tweak any of the virtual edits you made at any
time, then refreeze if you like...

If there's any disadvantage to this whole approach to editing, btw, it's
the proliferation of files -- both the 'wrapper' files that Samplitude
makes, which point into the original soundfiles; and (potentially) the
numerous versions of things I create, some affected in one way, some in
others. But with disk space so comparatively cheap, this is only a
file-wrangling problem.

I describe these features as they're implemented in Samplitude; while one
reason I chose it is that it pioneered 'virtual' (non-destructive) editing
as a dominant paradigm, I have to believe that many other packages have
adopted this strategy by now...!

Best regards,


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