Subject: Re: [linux-audio-dev] LADSPA and run_adding()
From: David Olofson (david_AT_gardena.net)
Date: Sun Nov 19 2000 - 13:07:39 EET
On Sat, 18 Nov 2000, Paul Barton-Davis wrote:
> >> i would really like to once again voice my opinion that run_adding()
> >> should be the default mode of operation for all LADSPA plugins.
> >
> >--votes;
> >
> >I'm still not convinced. I like to keep things simple. For me, LADSPA
> >plugins are loadable functions that process a given range of samples.
> >'run_adding()' goes further. It implies that plugins are signal
> >routers, etc ...
>
> I have to laugh - here's the exact opposite point of view from
> vst-plugins today, about processReplacing, which is the equivalent of
> LADSPA run():
>
> ----------------------------------------------------------------------
> Also, in a typical polyphonic synth implementing processReplacing, the first
> voice replaces the data and additional voices pass over the same buffer
> accumulating into it. So, the performance advantage of implementing
> processReplacing is probably very small. I bothered to implement it with my
> first synths and couldn't tell the difference so haven't bothered with later
> ones.
> ----------------------------------------------------------------------
This is what I'm thinking about, and it's not an unusual scenario -
most multichannel systems tend to have some of these "multichannel
mixing points".
As for the above, again, clearing a buffer when you *don't* want
run_adding() is both faster and easier than adding buffers and doing
external mixing when you *do*.
(Those who really care make sure that most plugins provide *both*
versions, so that hosts doing non-standard things won't suffer.)
//David
.- M u C o S -------------------------. .- David Olofson --------.
| A Free/Open Source | | Audio Hacker |
| Plugin and Integration Standard | | Linux Advocate |
| for | | Open Source Advocate |
| Professional and Consumer | | Singer |
| Multimedia | | Songwriter |
`-----> http://www.linuxdj.com/mucos -' `---> david_AT_linuxdj.com -'
This archive was generated by hypermail 2b28 : Sun Nov 19 2000 - 15:33:57 EET