Subject: Re: [linux-audio-dev] gain curves, interpolation, etc.
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Wed Nov 29 2000 - 19:09:33 EET
On Wed, Nov 29, 2000 at 11:43:32AM -0500, Paul Barton-Davis wrote:
> well, there are two things here: first, most existing DAW's *do*
> expose the user to exponential curves. a typical approach is to offer
> a palette of possible xfade "shapes":
Interesting. Most of the "semi-pro" stuff I've used only lets you work
with linear-ish segments, and applies whatever curve to that.
> second, as far as gain curves in general, keep in mind that as david
> bartold was so kind to point out to me, macromedia owns a patent on
> the use of a visible control curve to manage waveform volume. the
> patent very viable to me. so its unlikely that any open source project
> will work that way. i haven't figured out the generic alternative yet.
Um, wow, isn't there prior art? I could swear I used gain curve software
on an amiga in the late 80's. Though come to think of it I think I remeber
this discussion from when I first subscribed.
> however, for edit-point xfades i am thinking more along the lines of
> combining the "palette" approach with the way snd does things with a
> more immediate method of specifying xfade length:
That sounds good.
> well, i haven't checked protools in a while (BTW - did anybody
> download the free version ? i think the idea of printing out the
> manual is an excellent one, but haven't gotten to it yet). but i have
> never thought of xfades as existing from track-to-track. they exist at
> the points where you insert material from some place into a track.
Saw a mention of it recently, they were talking about choping up
multiple takes of one line from a song, as in "I'll have that bit from
that take, that bit from that take" without merging the takes. Maybe I
got the wrong end of the stick.
> in case its not obvious, despite the fact that i don't plan to add a
> mixer component to ardour-as-DAW any time soon, managing xfades at
> edit points is most sensibly done (i think) by adding complete support
> for gain curves, hence this thread.
Totaly. Solving the generic case is good.
- Steve
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