Re: [LAU] Musical Score Editors - some advice for beginners

On Thursday, September 24, 2009, Emiliano Grilli wrote:
> Werner Schweer <ws@email-addr-hidden> writes:
> > MuseScore is still being developed.
>
> I'm trying version 0.9.5 and I find it a really nice
> application. Although I'm not that confindent with written music, I'm
> willing to learn: and musescore has a great appeal in this regard.
>
> However, I'm not able to connect it with external MIDI synthesizers. I
> see alsa midi ports but nothing seems to pass through them (tried
> with kmidimon). If I select to use the MIDI out in the preferences the
> song won't start at all, while with the internal synth all is working
> good.
>
> Any hints on this problem?

When you start KMidimon first, and then you start MuseScore from a terminal
session, you can see the following messages:

$ mscore
RtcTimer:: fatal error: open /dev/rtc failed: Device or resource busy
MidiSeq:start(): no midi timer available
Cannot start I/O
sequencer init failed

This happens because KMidimon creates an ALSA Sequencer queue, and ALSA uses
the RTC device for their own sequencer, so mscore finds that it is busy when
tries to open it. The same happens if you start arecordmidi before mscore, or
any other program that uses ALSA sequencer queues.

You can use aseqdump instead of KMidimon to monitor the MIDI events coming
from mscore, because aseqdump doesn't display the event's timestamps so it
doesn't need to use a queue. You can also start MuseScore first, and KMidimon
later. Or tell the ALSA sequencer to use a different timer source by default.
These are not real solutions, only workarounds. The solution would be to
implement an ALSA timer in MuseScore, or even better: use the ALSA sequencer
scheduling services instead of an internal timer.

I would like to contribute with code to solve this, because I like many of the
program features, but the project leader says that he is going to drop ALSA
replacing it with Jack MIDI, so implementing better ALSA support for this
project would be losing the time.

Regards,
Pedro
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
Received on Fri Sep 25 20:15:11 2009