Re: [fluid-dev] What is MIDI driver?

[Nikolay Shaplov]

В письме от воскресенье, 13 февраля 2022 г. 14:23:10 MSK пользователь Orm 
Finnendahl написал:

Thanks for detailed explanation, it make things much more clear.

There are two more things I'd like to ask.

First, ALSA Sequencer System, it is technically what? I it is not service 
(neither in systemd sense, not in common sense). It is not server. It has no 
separate .so library, it is not listed in ps -aux. How should i write|think 
about it "ALSA Sequencer System is [service|server|API|whatever] that do this, 
this and that". How I should refer to it? This point is omitted in every doc 
I've read. 

> As MIDI currently is mostly implemented by USB standard compliant
> hardware, it gets recognized by the system, the appropriate driver is
> installed automatically and it works out of the box (that's the "raw"
> part). On top of that there is the "alsa-seq" which adds virtual
> ports, timing and such for the communication between applications.
I saw alsa_raw in --help, but did not understand what does it mean, before I 
read you explanation.
I guess it is exactly what I need for my simple home MIDI usage: plug keyboard 
and start playing.

I tried to use it:
fluidsynth -a pulseaudio -m alsa_raw -g 10 -r 48000 -p midiC1D0 /usr/share/
sounds/sf3/default-GM.sf3

and got an error:

ALSA lib rawmidi_hw.c:235:(snd_rawmidi_hw_open) open /dev/snd/midiC0D0 failed: 
No such file or directory

It turned out that I have /dev/snd/midiC1D0

I trued to pass device name via -p: midiC1D0, /dev/snd/midiC1D0 and so on, but 
did not success.

creating symlink from midiC1D0 to midiC0D0 solves the problem though.

This issue is not discussed anywhere I can found. So, are there any way to 
make it work without creating a symlink? I am running Debian Buster, with  
FluidSynth 2.1.7

-- 
Nikolay Shaplov aka Nataraj
Fuzzing Engineer at Postgres Professional
Matrix IM: @dhyan:nataraj.su