[LAU] [Rosegarden-user] timing penalty?

[alex stone]

Chris, no problem for you. I'm talking and asking about performance
timing at data level across multiple apps, not the port structure
itself. Jackmidi does show alsa ports when it's in seq, so no problem
there aside from the renaming challenge, in qjackctl at least.

So you can keep right on enjoying yourself. :)

Alex.





On Sat, Apr 11, 2009 at 11:28 PM, Christopher Cherrett
<stuff at trackingsolutions.ca> wrote:
> I thought that the newest jack will create jack midi ports out of alsa midi
> ports for you if the driver was set to seq.
>
> I really hope this does not pose a problem for me as I am almost finished
> putting in the interface for program and bank changes on the fly. The only
> thing left to do is finish the new ruler that will visually indicate where
> the program changes are.
>
> Are you running program changes on multiple tracks? Or is this just
> happening on one track?
>
> -------- Original Message  --------
> Subject: [Rosegarden-user] timing penalty?
> From: alex stone <compose59 at gmail.com>
> To: rosegarden-user <rosegarden-user at lists.sourceforge.net>, LAU Mail List
> <linux-audio-user at lists.linuxaudio.org>
> Date: 04/11/09 12:30
>>
>> I've been conducting a couple of experiments related to timing, and in
>> particular a rapid program change sequence, between Rosegarden, using
>> Alsamidi, through A2jmidid, to Linuxsampler.
>>
>> 1.) When i use alsamidi in both RG and LS, timing is reasonable, but i
>> get the occasional blip if too many PChanges happen in quick
>> succession. (And as a relative scale, we're talking about a sequence
>> of 1/64 notes, with a PC for each one, and additional volume CC
>> changes as well, at about 140 bpm.)
>>
>> 2.) When i use alsamidi in RG, and a2jmidid through to LS jackmidi,
>> timing has improved, but still the occasional missed PC.
>>
>>
>> So using a2jmidid seems to be a step forward, but my question is, is
>> there a 'penalty' of some sort for using it in bridging format, and if
>> so, what is it?
>>
>>
>> 3.) When  i use jackmidi native apps, running Muse and LS, for
>> example, the timing is good, and i don't seem to miss fewer PChanges.
>>
>> (Which doesn't mean i'm giving up on RG. It has too many essential
>> tools that help me workflow wise.)
>>
>>
>> Final Question.
>> If we use an RT kernel (which i am, being 2.6.29-RT in 64studio 3.0),
>> with 1024HZ (or higher) for timing, what can we do after that, in
>> jack, a2jmidid, RG, LS, etc.., to ensure that midi timing (Alsa or
>> Jack) is pristine, and the combination of apps has the best change of
>> coping with rapid, and high volume, midi data being sent?
>>
>> I'm trying to finesse the midi timing and midi data management across
>> the board, and get it as good as possible. (It's already good. This is
>> about the....extra 10%.)
>>
>> I'm definitely in favour of using jackmidi based on my modest and
>> subjective experience, but i'd like to stick with RG for the power of
>> it's toolset for workflow. (Plus a thousand other good reasons to use
>> it.)
>>
>> So if anyone has ideas, and tips, on raising the midi data flow
>> precision in transistion between the above apps, and tips or compile
>> flags to do this at build time, or runtime, i'd appreciate some
>> insight.
>>
>> I've applied the usual tweaks across all the apps, and have Jack
>> running at 128/2/48000, with no xruns during normal operation.
>>
>> Alex.
>>
>> 64studio 64bit 3.0 (beta 3), on an AMD64 5600+ dual core, with 4GB ram.
>> M-Audio Delta 44 soundcard.
>>
>>
>> Parchment Studios (It started as a joke...)
>>
>>
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>
>
>



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