[LAU] Is -Xalsarawidi the same as -Xraw or -Xseq?

[Paul Davis]

One other note: in Jack1, to aid with "back compatibility", if you were to
use -Xseq, Jack1 will interpret that as "use my embedded version of
a2jmidid".

as noted by others, unless you do not care about timing, you should never
use -Xraw. You should use -Xseq only with Jack1, where it is equivalent to
starting up a2jmidid -e, which is the recommended approach for Jack2.

On Mon, Jun 18, 2018 at 9:55 AM, Victor A. Stoichita <victor at svictor.net>
wrote:

>
> Le 18 Jun 2018, Paul Davis <paul at linuxaudiosystems.com> a écrit :
>
>> Just a note. You should NEVER use ALSA raw MIDI with JACK unless you
>> don't care about timing in any way.
>>
> (…)
>
>> And for those wierdos/smart folks/rebels out there using Jack1, remember
>> that a2jmidid is builtin to Jack1 itself.
>>
>
> Thanks Paul for the hints! I do care about timing, that’s why I’m
> researching this. I think that I may run into some jitter when recording
> midi in Ardour or Qtractor (or I really play worse than I thought!). That’s
> what got me to the advice of using -Xalsarawmidi combined with a2jmidid.
> I’m still not sure whether this is the same as -Xseq or -Xraw.
>
> For the background I got the explanation by Fons Adriaensen (10 years ago)
> relayed at https://wiki.linuxaudio.org/faq/start#qwhat_is_the_differenc
> e_between_jack-midi_and_alsa-midi
>
> Then on the same wiki I also got this "interesting" comment:
>
>> "Interestingly, JACK developers (by way of Paul Davis) recommend using
>> a2jmidid for exposing raw midi ports (https://community.ardour.org/
>> node/4336), while the a2jmidid author recommends using the '-X raw' flag
>> for JACK (https://gna.org/bugs/index.php?23272)."
>>
>
> That made me wonder what I should do. gna.org is down so I couldn’t
> check/understand the second comment.
>
> I tried to locate the current repo of a2jmidid but could only find this
> mirror (?) referenced by the Arch packagers:
> http://repo.or.cz/a2jmidid.git There it says:
>
>> "Main goal of this project is to ease usage of legacy, not JACK-ified
>> apps, in a JACK MIDI enabled system."
>>
>
> If I only use Ardour, Yoshimi, Qmidiarp and mididings (all of which can do
> jack-midi on their own), should I still connect them through a2jmidid just
> for the sake of timing?
> I’d be ready to join the Jack1 rebels if this could simplify my midi
> setup. I only need one server on one local computer, no dbus etc. But I
> also need low latency for live performances and some dsp overhead. On these
> topics I’m confronted with another decade of contradictory informations
> The feature comparison on the jack website [1] seems to give a slight
> advantage to jack2 in my case, mainly because of "Supports multiple
> processors (SMP)" (I do have parallel subgraphs in my setup). That had
> prompted me to switch to jack2 some 3 or 4 years ago. Now the state of midi
> support makes me look back…
>
> So I wonder:
> - if I use jack2 and a2jmidid, what -X option should I give to  jackd at
> startup? Will that reproduce the native behavior  of jack1?
> - are there recent benchmarks to compare jack1 vs jack2 regarding  latency
> and dsp load?
>
> Cheers,
> Victor
>
> [1] https://github.com/jackaudio/jackaudio.github.com/wiki/Q_dif
> ference_jack1_jack2
>
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