Re: [linux-audio-dev] New LADSPA Version - Issues Resolved?

New Message Reply About this list Date view Thread view Subject view Author view Other groups

Subject: Re: [linux-audio-dev] New LADSPA Version - Issues Resolved?
From: Kai Vehmanen (kaiv_AT_wakkanet.fi)
Date: ke maalis 08 2000 - 20:49:13 EST


On Wed, 8 Mar 2000, Richard W.E. Furse wrote:

> I think this version meets basic requirements for a simple plugin API. It
> still only supports float types, but I think that's sensible at this level.

Yep, looks good to me. Btw; is someone working on a C++ LADSPA class (or
intents to write one)?

I'm still trying to come up with a efficient way to mix these C-algorithms
with ecasound's higher level effect interface. In ecasound, chain operators
(=effects) don't handle the sample buffers directly. Instead, they
use special iterator objects for audio input/output. Here's a sample:

--cut--
void EFFECT_AMPLIFY::process(void) {
  i.begin();
  while(!i.end()) {
    *i.current() = *i.current() * multiplier;
    i.next();
  }
}
--cut--

'i' is an object of class SAMPLE_ITERATOR. This iterates through
all samples (of possibly multi-channel stream). Iterator class
makes sure, that samples are iterated as efficiently as possible
(depending on channel layout, etc). Other iterator types are
SAMPLE_ITERATOR_CHANNEL (iterate samples of one specific channel),
SAMPLE_ITERATOR_CHANNELS (iterate through all samples, channel
at a time) and SAMPLE_ITERATOR_INTERLEAVED (iterate through all
samples, sample frame at a time).

All variables are typedef'ed floats. The actual sample data is
stored into STL vectors. Member functions are of course all
inlined (and no virtual functions). But, but, writing a wrapper
for LADPSA plugins isn't going to be an easy task. I basicly have
to write an intermediate buffering layer that communicates with
the plugins.

-- 
Kai Vehmanen <kaiv_AT_wakkanet.fi> -------- CS, University of Turku, Finland
 . http://www.wakkanet.fi/ecasound/ - linux multitrack audio processing
 . http://www.wakkanet.fi/sculpscape/ - ambient-idm-rock-... mp3/ra/wav


New Message Reply About this list Date view Thread view Subject view Author view Other groups

This archive was generated by hypermail 2b28 : su maalis 12 2000 - 09:14:05 EST