Re: [fluid-dev] One output per channel

[Bernat Arlandis i Mañó]

Ebrahim Mayat escrigué:
> > Also, I've fixed the reverb and chorus effects in multichannel mode so 
> > they're applied to every channel, instead of mixing the effects separately.
> >     
>
> This would be a powerful feature allowing for inserts directly from
> fluidsynth into a live mix. Would this entail a significant CPU
> overhead ?
> Even so, this could still be very effective on dual- and multi-core
> machines. 
>
>   
It scales pretty well, the reverb/chorus processing time multiplies by 
the number of channels, but still acceptable. With all 16 channels I got 
around 70% CPU load in my tests with an AMD64 2Ghz. There's some room 
for improvement since the reverb and chorus units take a constant amount 
of CPU even when the channel is idle. Setting up less channels speeds 
things up.
> Could LADSPA plugins be easily incorporated in the same way as the
> chorus and reverb effects in multichannel mode or would this require a
> major overhaul ? In other words, how do fluid reverb/chorus and LADSPA
> fit in the audio signal chain. I imagine the current signal path to
> resemble something like this
>
> noteon --> chorus/reverb --> --> jack output port --> Jack Rack --->
> LADSPA --> ALSA 
>
> ...or is this incorrect ? 
>
>   
I don't understand what you're trying to say. FS does just the first 
three steps. You can disable reverb/chorus in FS and apply them 
externally per channel from Jack, with the only drawback that the amount 
of effects can't be controlled by MIDI then.
> I don't see how the two effects ports fit into the whole scheme. 
>   
I've removed these. The reverb and chorus effects were getting mixed to 
these ports instead of being mixed with the audio channels. I don't know 
what this could be useful. Now the effects are mixed into the 
corresponding audio channel.
> LADSPA functionality in FS could be effective when using FS in live situations 
> while
> for recording LADSPA could be used as inserts or sends from within the host DAW.
>
>   
I'd like to include support to replace internal reverb/chorus with 
LADSPA plugins, I guess this is what you mean.  Getting back the old 
LADSPA implementation doesn't seem necessary since there are more 
user-friendly Jack tools to do the same now, correct me if I'm wrong.

--
Bernat Arlandis i Mañó