[PD] MIDI In-to-Out Latency

Pedro Lopes pedro.lopes at ist.utl.pt
Sun Jun 6 01:47:43 CEST 2010


Just to see if I got that right, the rip is:

keyboard -> YOKE in -> YOKE OUT -> PD IN -> PD OUT  -> YOKE IN -> YOKE OUT
-> CUBASE IN

>The sluggish response is clearly due to Pd. Also, it's consistent whether
Pd's patch window is in or >out of edit mode.
How can you be sure? You are making two trips using that patching software
(I confess I had no clue what MIDI-OX was previous to your thread), there's
latency in all of the above hops (MIDI message passing through softwares) .

Do you tried to see how is Pd's latency in a "simple play sine wave with
MIDI note" patch? that will give you the response time of keyboard -> PD.
Then test the oposite, sending PD to your soundcard MIDI and playing some
device or other solution, allowing you to test the output (by generating a
MIDI message within PD and route it out od PD).

Maybe those measures could be helpful for now,
Best regards and good luck,
Pedro Lopes
p.s. just for comparison I use MIDI in PD in WinXP without any noticeable
latency, although only in Linux I do fancy patching in-out and have no
noticeable latency (using everything in realtime).

On Sun, Jun 6, 2010 at 12:26 AM, Jim Aikin <midiguru23 at sbcglobal.net> wrote:

> I'm running 0.41.4 Extended on a 64-bit Windows 7 system. I've installed
> MIDI Yoke to route incoming MIDI from my keyboard through Pd and thence to
> Cubase 5.1.
>
> What I'm finding is that with the simplest possible notein-to-noteout
> patch, Pd's MIDI throughput latency is very consistently on the order of
> 100ms -- plainly unacceptable for real-time performance. Needless to say,
> Cubase is using ASIO, and has no problem producing low-latency MIDI response
> when I use a direct MIDI input. The sluggish response is clearly due to Pd.
> Also, it's consistent whether Pd's patch window is in or out of edit mode.
>
> To test whether MIDI Yoke might be the culprit, I opened MIDI-Ox and routed
> the physical MIDI input to a MIDI Yoke channel. The latency was maybe a tiny
> bit greater than via a direct routing into Cubase (maybe), but it was much,
> much less than with Pd.
>
> The section in the Pd manual on scheduling doesn't mention MIDI latency at
> all; it's strictly about audio DSP load. I can't find anything else in the
> manual that seems even faintly relevant. I did find (somewhere ... on the
> wiki?) a mention that the timing of metro would be improved if I ran with
> the command line pd -noaudio, so I opened a Command Prompt and tried that.
> It didn't change anything.
>
> It seems very odd to me that Pd can handle audio streams without glitching,
> yet it can't process three bytes of MIDI data in less than 100ms. Is this
> user error on my part? Can anyone suggest how I can reduce or eliminate the
> delay? Thanks for any tips!
>
> --Jim Aikin
>
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-- 
Pedro Lopes
contacto: jazz at radiozero.pt
website: http://web.ist.utl.pt/Pedro.Lopes
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