[LAD] Fw: Re: Some questions about the Jack callback

Fons Adriaensen fons at linuxaudio.org
Sun Sep 21 09:19:06 UTC 2014

On Sat, Sep 20, 2014 at 06:21:02PM -0400, Mark D. McCurry wrote:

> Darn, I was hoping for you to point out some sort of interesting way of working
> with pscho-acoustic space.
> I have worked with it some, but I surely have large gaps in the details and
> possible best ways of working with it.

Critical bandwidths would be something that maybe can be exploited 
without introducing too much complexity.

Almost all lossy audio compression schemes are based on this.
So one way would be to explore in how far you could parametrise
e.g. an ogg or mp3 decoder and turn it into a synth engine.

> > 'The user has full control over the full spectrum'. The question is
> > if this is necessary - if all that detail is really perceptible in
> > the final output. If it is not, then there is no point in generating
> > it in the first place.
> I'd side with it not really being needed, but going for a more restricted
> interface does require careful though on how the user is going to interact with
> the software.

One way would be to keep the user interface, but to reduce the user
input before it's used. That's cheating of course, but I don't see any
fundamental reason why that wouldn't be acceptable... this is about
a musical instrument, not a scientific tool. Which means that the user
will explore things instead of having a predefined input that leads
to a certain result.

> > There's been a lot of research the last years into sparse representation
> > of some kinds of signals and into compressive sampling, but these things
> > are not simple from a computational POV. And all of it is about efficiently
> > capturing signals, not generating them.
> Yeah, that's the side of things that I've been exposed to.
> Lots of compressed sensing and sparse model based representations used to
> extract information out and manipulate it.

Fascinating stuff, isn't it ? I only got aware of this two years or
so ago, and worked my way through some of the fundamental papers by
Candès, Donoho e.a. If you have pointers to any material related to
audio applications of compressive sensing I'd be very interested.



A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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