[PD] pd-lork and midi on osX

cyrille henry ch at chnry.net
Sun May 5 11:40:31 CEST 2019


Thanks for looking at this problem.

The test patch is very similar to my situation.
I use a DMX interface that is visible by a computer as a midi device over a USB connection. It allow to control lighting device from any musical software.
This interface use class compliant usb/midi driver and control 2 dmx univers (i.e 1024 lighting devices)

a DMX frame is about 20ms. So I need to send 1024 value every 20ms.
10 years ago, windows drivers did allow only 1 midi message every ms, so it was not possible to use this interface on windows. But I was working fine on osX and linux.
I did not test on windows since. It still work on linux. It works on pd-extended on osX but not with pd vanilla 0.49 on osX. I did not test any other pd version on osX because I don't have a mac at home. I'll make more test in few weeks.
(when I says that it did not work, I mean that you can't send 1024 value every 20ms, but you can send 100 every 20ms)

If you try my test patch with a USB/MIDI interface, you will face problems : midi is to slow, so pd will hang or data will be lost.
You should only use this test patch with something that can receive midi that fast : a virtual port, or a hardware that did not convert this data to midi informations.

I will try sending 50 messages every ms, but "almost gone" is not satisfying.


Le 04/05/2019 à 03:11, Christof Ressi a écrit :
> Hi, I don't know what your actual patch looks like, but I noticed that when I spread the MIDI messages evenly by sending 50 messages every 1 ms instead of 1024 every 20 ms, the delay on my USB interface is almost gone. Maybe this improves your situation. The real problem, however, is that sending MIDI on Windows and macOS via portmidi is currently a blocking operation and this has to be fixed.
> Christof
>> Gesendet: Freitag, 03. Mai 2019 um 10:19 Uhr
>> Von: "cyrille henry" <ch at chnry.net>
>> An: "pd-list at lists.iem.at" <pd-list at lists.iem.at>
>> Betreff: [PD] pd-lork and midi on osX
>> Hello,
>> I'm trying to find a solution for my project where large amount of midi data should be send.
>> This bug prevent me to use latest vanilla : https://github.com/pure-data/pure-data/issues/581
>> and I want to avoid using pd-extended.
>> The final project will run on osX, but I don't have a computer to test on this platform.
>> Can someone tell me if pd-l2ork will do a better job at sending midi data at fast rate?
>> thanks
>> Cyrille
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