RE: [iiwusynth-devel] Multi channel output and number of midi channels

[M. Nentwig]

Hei,

sorry, I did not have the time for a proper reply until now.

> For multi-channel output, the output signals of the fx are not merged
> back into the multichannel output. They are ouput seperately in the
> fx_left and fx_right buffers.

OK. So when the chorus (or reverb) is on, its output is merged to master
out. If it's disabled, the corresponding Fx send goes to an effects
output.

> We just need to check that the changes I made
> for the multi-channel output doesn't cause problems for the LADPSA Fx
> code.

I'll have to extend that to multichannel output. Until that is done, I'd
recommend compiling without ladspa...

> Have you ever considered implementing your LADSPA plugging routing
> as a Jack client? That would make it useful for other applications
> as well.

I have seriously thought about it. But I can't get Jack working. And I
have a feeling, that it's not ready yet. Just a couple of weeks ago, the
jack portnames were renamed, breaking all old Jack applications (at
least that's how I understood it). And practically each time I start
experimenting with Jack I get a hard kernel lockup in the end.

The 'synth/sampler dream machine, that I can think of is just one
command-line program that does not use any non-standard 'OS' features
(like audio mixing). Think of it as the equivalent of a 19 '' rack like
Korg 01 or Roland JV 2080 - plug in MIDI and audio, feed in a program
and play. The open question is, how far this is compatible with
iiwu/fluidsynth as a lean & mean library.

BTW, if you or anybody is interested in the GUI I wrote, please let me
know (requires perl Tk and a MIDI kbd).

> I saw your email on the jack mailing list. Jack's been running on my
> machine all weekend, with iiwusynth connected using 10 stereo output
> channels. No xruns, even when sync'ing the disks. I do use a
> low-latency
> kernel and did a 'hdparm -c1 -d1 /dev/hda'.

I once tried the low-latency patches. It didn't fix the jack problem,
and PCMCIA didn't work anymore. Probably it can be solved, if I just
throw enough time at the problem.

Now my floppy disk drive didn't come with me to the office this morning
:(
I'll send a working example for a working LADSPA configuration soon.

I think I'll spend some time programming later on. Let's see, if I can
get that multi channel audio working.

Cheers

Markus

PS: About the 'streaming-samples-from-disk' discussion: From my limited
perspective, this sounds like a -huge- amount of work without any real
benefit.
OK, Gigasampler does just that, but where do we get the free
'Giga'samples from? Somebody has to host them, and somebody has to
create them. I spent yesterday's evening resulting in 2 MB worth of
sample memory. I just cannot imagine that there are or will be big
enough samples to justify that feature.
And the memory size of a typical PCs increases all the time. So it may
be, that all this effort is 'useful' only for a short span of time.