VST from a DSP hackers perspective (was Re: [music-dsp] Google -2Human interaction - 0)

Jeff Chandler jeffc030 at earthlink.net
Mon Jun 14 17:21:26 EDT 2004


How about some insight on the DXi SDK from Cakewalk,
which is based on Microsofts DirectShow.  I like the idea that it
easy to incorporate MFC, and therefore easly create a UI (although
windows compatible only).

The trouble that I am running into, is setting up communication between
the plugin, and the UI.  All of the examples update the parameters via
CMediaParams every time process() is called, rather than when the
parameters are changed (not in real-time).  This is inefficient, when I need
to make calculations based on the paramters ( filter coefficients).

Also I would like to be able to access objects in the plugin from the
user-interface,
for example so I can draw the frequency response of a filter (I need access
to my filter
class, located in the plug-in class).

Thanks, Jeff


----- Original Message ----- 
From: <gogins at pipeline.com>
To: <music-dsp at ceait.calarts.edu>
Sent: Sunday, June 13, 2004 1:07 PM
Subject: RE: VST from a DSP hackers perspective (was Re: [music-dsp]
Google -2Human interaction - 0)


VST advantages:

- Simple (very important)
- Therefore efficient (also very important).
- Works on Mac and Windows.
- Handles audio I/O, control I/O (MIDI), parameter I/O.

VST disadvantages:

- Too simple.
- Poorly specified and poorly documented.
- Life cycle (sequence of host calls) poorly specified and documented,
  in particular.
- There should be a host API, but there isn't.
- Host requirements are not spelled out.
- Uses registration of four-character IDs, should use globally unique
  identifiers not requiring registration.
- You can get it to work on Linux or Unix, but the documentation is
clueless.
- All control I/O is MIDI (should be more precise, more abstract, more
  extensible).
- All parameter control numbers are normalized (not sure this is really
  a problem).
- VST plugins can't host other VST plugins without oodles of work
  (because there is no host API).
- Not internally extensible (plugins should be able to define new
  opcodes with new input and output data types, using namespaces or GUIDs
  for disambiguation).

VST is like the QWERTY keyboard: a decent first stab at solving a problem
that becomes cast in stone thanks to wide acceptance and so and obstructs
further progress. If it had been internally extensible this might not have
happened.


Original Message:
-----------------
From: Jay Vaughan jv at access-music.de
Date: Sun, 13 Jun 2004 21:16:08 +0200
To: music-dsp at ceait.calarts.edu
Subject: VST from a DSP hackers perspective (was Re: [music-dsp] Google -2
Human interaction - 0)


>  > OK, OK, I get the point - I'll use Google & search engines for
>  > everything from now on.
>Oh c'mon richard, we weren't unfriendly were we...
>It's just that your question IS covered by the FAQ - or in this case
>musicdsp Wiki - so we pointed to that. And google has a LOT of info about
>your particular question...

To be honest, I thought a 'music-dsp perspective on VST' would've
been, personally, an interesting thread ... its a shame that it was
nipped in the bud as an intellectual exercise, not just an
encouraging thread.

Yeah, we can all download VST SDK and join the fray.  Sure, there is a FAQ.

But what are the DSP-specific thoughts on VST as an API, and as a
design?  Its rapidly becoming a 'standardized, public format plugin',
now that it runs on pretty much every platform under the sun, and
there -are- some interesting VST hacks out there ...

So, why not ask the music-dsp core to commit to a bit of pedantry on
the subject?  What -do- you guys think of the VST system, as a whole,
for sound-generation systems?

 From my perspective, I see VST as pretty much a simple i/o->runloop()
style API, I don't find its overall design to be particularly
different from any other batch-processing system I've seen over the
years, though I certainly recognize that it is sufficient for the
general task of making sound from C and C++ code ...

But, the DSP side of things is something else.  What about it?  If
you had your own druthers for an open, public
audio-generating/control API system, from a DSP stance, in what
direction would you go?

Anyone played with CHUCK yet?  How does -that- compare to VST?

-- 

;

Jay Vaughan
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