Re: [Audacity-devel] Real-time effects stacks

[Michael C. <mc...@gm...>]

2008/5/5, Jorge Rodriguez <jro...@ma...>:
> But, it did give me an interesting idea, which is very similar and I think
> has the best of both worlds. Each track would have an effects stack, but
> instead of being applied to the real-time buffer or to the file itself
> destructively, what if a copy of the audio data was made, and the effects
> rendered to it immediately and destructively, and Audacity would keep both
> versions around? The "dry" version of the audio data would be kept around
> for if the user turns effects off or if Audacity needs to re-render the
> effects stack, and the "wet" version of the audio data is kept around
> playback and exporting?
>
> I like this solution because it involves no real-time effects rendering, it
> allows the exporting to happen exactly as fast as it happens right now, and
> it does not significantly increase the requirements on hardware, other than
> the extra hard drive space needed to store two versions of each track with
> effects. What do you guys think?
This is essentially what I meant by destructive on-demand effect
stacks.  I should exlain the on-demand part - it was proposed to get
the best of both worlds, some other things might be considered.  By
On-Demand, I mean that when the user clicks on the 50% mark and hits
play, the effect does not process the sound from start to end, but
instead jumps to the 50% mark and starts processing there immediately
so the user can hear the effect instantly.   Currently effects are
processed from the start to end in linear progression.

As a starting point I am implementing this for peak summary data,
which is used to view the waveform.  This is not an effect, but the
behavior and structure is similar and we are thinking to integrate it
with this system.

Note the naive implementation of this will not work for all audacity
effects.  One example is reverse or repeat.  These effects use
information from a different part of the waveform to compute an
arbitrary chunk of sound, and the on-demand stack just won't make
sense for those.  In most DAWs, these effects are simply not allowed
as being capable of having stack behavior.  However, I don't think
Audacity currently makes a distinction between those, so its something
to consider.



>
> Finally, I should let you know that I'm not a Summer of Code student, I'm a
> professional software developer who is also a recording musician, and thus
> I'm not eligible to do SoC. Also, I was expressing my WTF on your continued
> usage of CVS when SVN has been out for four years. In any case, I'll pull
> Audacity out of CVS soon (ick) and start mucking around in the source code.
>
> PS: Where's the bug tracker? I want to look up why muted tracks aren't saved
> to the project file or recognized during export.
>
>
> --
> Jorge Rodriguez
> Matrieya Studios, LLC
> Email: jro...@ma...
>  Phone: (919) 757-3066
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