[PD] Audio drops when I refresh many text in scrolline by externalMIDIcontrol.

Andy Farnell padawan12 at obiwannabe.co.uk
Sat Oct 20 08:54:32 CEST 2007

On Fri, 19 Oct 2007 19:51:51 +0200
Derek Holzer <derek at umatic.nl> wrote:

> As for multitrack recording, why reinvent the wheel? 
> PD->QJackCtl->Ardour with LADSPA plugins inserted in the tracks (or 
> using JackRack) gives you everything you'd ever need for most situations.

I've happily streamed 12 or more tracks down to disk through Jack->Ardour.
Create a multi-output [dac 1 2 3 4 5 6 7 8...] and wire these up to
Ardour inputs in Jack, let Ardour sweat over the disk buffering, it does
the job very well indeed.

> I've had some trouble with hardware MIDI stuff before. Best to just send 
> it directly to the parts of the patch you want, and not send it to a GUI 
> fader onscreen.

Some possible solutions:

1) Decimate the controller bandwidth. When you move a MIDI fader many fader
boxes flood the channel with far more CC data than is needed. If you use [change]
with a [metro] and [float] you can just catch the start, end and timed (100ms)
samples between a fader movement, then interpolate it with [line~] where you need
a smooth signal rate control.

2) Use OSC with an external MIDI-OSC bridge, it's just nicer. MIDI interfaces 
generally uses a UART with one register and interrupt driven I/O, which is
primitive compared to OSC on a buffered socket.

3) Never go *through* a GUI slider in Pd. If you must have dual use of mouse
and fader box then rig up a "dual gang" display/control. If the data comes 
from the faderbox then it's routed directly to the control destination through
a [float] and the slider is updated periodically. If the data comes from the
slider then it updates the [float].

4) Build a sperate mixer interface in C. I used Qt to hack together a 
very simple mixer board that sends UDP packets to [netreceive], and that
works a treat.

> Working around PD's crap GUI is one of the big 
> challenges. You're lucky you're on Linux, the problem is much worse for 
> OS X users.
> If I had my vote, we'd talk less about beer, political correctness and 
> world politics, and focus more on fixing this kind of stuff...
> best,
> derek
> Kuba Szczypek wrote:
> > Thank you Phil
> > 
> > Yes I have ram disk ready for use.
> > What about play some music, adding effects and write it to hard drive
> > in 8 tracks simultaneously? Since ram disk has limited capacity it must 
> > be written to hard drive. Then probably it will cause drop audio.
> > 
> > But my main problem now is related to understanding why I can do 
> > something by fader on screen without drops, and when I use fader on 
> > hardware MIDI then it give me hangs and drops.
> > 
> > Also I`m waiting for input from anyone who know PD and MAX and can give 
> > a comparing, with focus on possibilities to create complete
> > audio (or video) tool, not only for learn and fun, but also for using.
> > 
> > I`m would like to have base in pd or other program who can give me this 
> > possibilities.
> > 
> > Of course I can be wrong, and you may suggest me (for example) to use
> > external sequencer, external multitrack etc.
> > 
> > I seen on cycling`74 web page that they now recommending Ableton Live 
> > for sequencing. Question is why: because marketing or because MAX is too 
> > bad.
> > 
> > The same question I have related to pd.
> > Please forgive me if I have not elegant form, but I have bad english and 
> > I`m frustrated too long (by drops audio).
> > 
> > Best regards,
> > Kuba
> -- 
> derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
> ---Oblique Strategy # 42:
> "Destroy
> -nothing
> -the most important thing"
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