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Date:      Sun, 11 Nov 2018 13:01:47 +0100
From:      Hans Petter Selasky <hps@selasky.org>
To:        Clemens Ladisch <clemens@ladisch.de>, freebsd-multimedia@freebsd.org
Subject:   Re: jack_umidi - jack_midi_event_get() failed, lost MIDI event
Message-ID:  <af879174-08e6-6d59-e009-36f4dfad5bef@selasky.org>
In-Reply-To: <fc0c0433-3b4f-6673-0921-6ec9fe2ce77b@ladisch.de>
References:  <CAPe0dB=J-a4i3WWf%2Bzw7WHWEqmTx_Y_gRHjsjuxyFi1odhMDyQ@mail.gmail.com> <fc0c0433-3b4f-6673-0921-6ec9fe2ce77b@ladisch.de>

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On 11/11/18 8:11 AM, Clemens Ladisch wrote:
> Marcel Bonnet wrote:> Hello.
>> I wrote a program to send System Exclusive Messages to my Roland XP-30
>> Keyboard. This program (QStage) connects to jack_umidi .
>> I send  a burst of 4296 events every time I load a sysex file.
>>
>> My program does not print "NOTE LOST", so I suppose that "maybe" I am using
>> the API correctly. But jack_umidi is zombiffied DPRINTing hundreds times
>> the same error  only after I load the second or third sysexfile (even if
>> its the same file).
>>
>> "umidi_write:160: jack_midi_event_get() failed, lost MIDI event."
> 
> What timestamps (sample offsets) are you using?
> 
> Jack is all about sample-accurate event timing, so I suspect that events
> get lost because they cannot be transmitted at what Jack thinks is the
> desired time.
> 
>> I started jackd with a Midi BufSize > 4296 * 4 bytes
> 
> If you take care that events are not queued faster than they can be
> transmitted (about 3125 bytes/s), the buffer size should not matter.
> 

Did you try putting a delay between every of those MIDU sysex events. 
I'm afraid that somewhere along the road JACK MIDI will overflow.

Or group them like 10 MIDI events and then a 10 ms pause.

--HPS




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