Re: [Rosegarden-user] Rosegarden-user Digest, Vol 48, Issue 21

[jimmy <wg...@ya...>]

> Date: Fri, 14 May 2010 09:00:48 +0200
> From: Dieter Plaetinck <di...@pl...>
> On Fri, 14 May 2010 08:50:56 +0200
> Lars Ole Pontoppidan <lar...@gm...>
> wrote:
> 
> > Hi user group
> > 
> > Does anybody know a good way to merge two midi streams
> and record them
> > as one? Can I select two midi inputs for recording in
> rosegarden for
> > instance? Could I make some magic in jack to do it?
> > 
> > My situation is that I have a digital piano without
> pitchbend or
> > anything, and I am thinking about getting a little
> midi controller
> > with plenty of that stuff and merge record from the
> two devices. I
> > know you can get a hardware merge box, but I would
> rather do the
> > merging in software, any ideas?
> > 
> > Best regards,
> > Lars
> 
> alternatively/somewhat related to this, it would be nice to
> be able to
> merge 2 separate tracks into each other. then you could
> record the two
> track separately (either at the same time, on 2 different
> hardware
> ports, or one after the other)
> 
> Dieter

I think Alsa midi ports and Jack midi ports can accept multiple Midi connections so merging should not be a problem, no need for hardware midi merge devices.  The main problem would probably be the starting time of each of those Midi input in the merged Midi data stream.

You can connect any number of Midi device output to the Alsa "Midi Through" and they will be merged automatically into one Midi port (16 channels).

Not sure about RoseGarden, merging functionalities.  With Alsa, you can connect multiple midi devices directly to RoseGarden.  Altenately, you can connect multiple midi devices to Alsa "Midi Through" port then connect from "Midi Through" to RoseGarden.  I think you may need to load the kernel module:

   snd_seq_virmidi

to get Alsa "Midi Through" port (Alsa midi port 14).

I know I can use

   arecordmidi -p 14:0   newfile.mid

to record midi from the Alsa "Midi Through" port to "newfile.mid".  And I think arecordmidi won't start recording until it gets some data from the port.

I think there are a couple of midi routing apps out there that can probably do fancier merging via midi channel redirect.

By the way, there is also at least one Perl script to do Midi split of midi files into separate files, one per midi channels.  Don't remember if it does merge, too.

Jimmy