[LAU] transform midi Control Change 7 into velocity events?

[Philippe Hezaine]

Dominic Sacré a écrit :
> On Friday 21 November 2008 13:27:18 Philippe Hezaine wrote:
>> Bingo! I think it's the first time we get from a Lilypond file a midi
>> file with velocities values. But for all you're right. Note that I
>> cannot get a clean file with a loop in the same Rosegarden's session. I
>> have freezes and even crashes. Hence i output the midi from Rg through
>> mididings -> recording in Muse.
> 
> You probably need to disable "MIDI Thru Routing" in Rosegarden, otherwise 
> connecting Rg -> mididings -> Rg creates a MIDI feedback loop, and 
> Rosegarden doesn't like that...
> 

Unfortunatly it doesn't matter. I've tried different options and the
results are the same. For information, after a loop session in Rsgd,
when i quit (Ctrl-C) mididings i get this message:

/home/phil/python/mididings-CC7-to-velocity.py
^Cpython: /usr/include/boost/shared_ptr.hpp:315: T*
boost::shared_ptr<T>::operator->() const [with T = Backend]: Assertion
`px != 0' failed.
Abandon

I'm on Gentoo with pro-audio. Rosegarden 1.7.0. But all is done with my
"testing" computer and the onboard soundcard.

Otherwise with two sequencers, the console is clean.

>> The raw outcome is in attach.
> 
> This file shows the problem I mentioned, with multiple tracks on the same 
> channel. In your original MIDI file, the volume of the Hi-Hat and Congas is 
> constant, but in this one, the velocity varies. Are you sure that's what 
> you want?
> 

No, of course. It's a testing file, with some "deliberately holes" just
to study the results. The CC7 are created by the dynamics in Lilypond.
There are 11 levels: from  pppp (veloc = 43) to  sf (veloc = 127). And
you can even reconfigure the equivalences if you want.
If you are needed i'll put on my site the Merengue's sources. If you
don't know Lilypond you can always look at the pdf.

>> 1) You could see a little latency in the attacks.
> 
> You're using JACK transport to synchronize Rg and Muse?

Yes. And i've tried the recording in reverse order: Muse -> Rg. The
results are completely different. But i'm not sure it's a valuable
information. Perhaps i must check out my rtc configuration before.

> I can reproduce this latency, and it appears to depend on my JACK buffer 
> size. The recording seems to be off by one period, but I don't know yet why 
> this happens, or whose fault it is.

In the next days i'll install mididings on my other computer with a
Multiface and i'll try again.

> If you can get recording in Rg to work this won't be an issue.
> 
> But note that even with JACK transport out of the equation, there will be a 
> very slight latency, because unfortunately mididings doesn't preserve the 
> exact event timestamps. You may want to quantize the recorded data.
> 

Yes. It's not an issue for The Drummer's Free Art.

> 
> Cheers,
> 
> Dominic

All the best.

-- 
   Phil.
Superbonus-Project (Site principal) <http://superbonus.project.free.fr>

Superbonus-Project (Plate-forme d'échange):
<http://philippe.hezaine.free.fr>