Re: [Om-synth] issues with om

[Atte André Jensen]

Dave Robillard wrote:

Thanks for taking the time to comment on my thoughts. Your reply is as 
mild as I could hope for.

> This is the fault of whatever plugins you're using.  I don't currently
> check the realtime safe flags of the plugins (I should, yeah).  I may
> just have them not show up at all, which is the easy fix.  You might be
> running non realtime safe plugins that have CPU usage all over the
> place.

Never heard of that flag. Where can I investigate if a certain plugin 
has that set or not?

> Om itself is and always has been very strictly hard realtime safe, I can
> tell you that.

Ok, I see. This is still a bit problematic cause I don't have a chance 
to look at a plugin and tell how it will perform (except by trying 
things and avoiding the worst ones). So from the users point of view om 
is actually om-the-program-you-wrote + 
a-bunch-of-plugins-that-make-noise. Fo instance I realized the other 
week that the only nice sounding rotary speaker plugin has a latency at 
about 50 ms. This has nothing to do with om, but it still means that my 
friends will tell me "so you can't do a decent realtime organ sound in 
that om-thingy".

> These two are communication issues.  The bane of my goddamn existance,
> frankly.  I get it occasionally too, I'll have to slow things down a
> bit.
>
> It's a fun game of randomly increasing delays littered throughout the
> code until things usually work.  This is the one thing that makes me
> regret the seperate client/server model.

So you're saying that they can't be fixed? Hmm. Couldn't the race be 
avoided by having the client wait for the server to finish whatever 
needs to be done before proceeding?

> That would be because I didn't have a keyboard with me until now. ;)
> Hold pedal support will come soon, now that I do.

Nice...

> Are you running a realtime patched kernel? (latency, not permissions)

I'm pretty sure, but I'll get back to you on this one...

> A (better) DSSI sampler plugin would allow you to play samples in Om.
> You can right now with the sampler that comes with the DSSI
> distribution, but it's a pretty trivial thing.

And as mentioned it crashes here when I change the root pitch :-(

> Dynamic voice allocation will come in the form of a special node with an
> "activate voice" input (ie if it's high, the voice will run, or maybe
> vice versa).  This is a very old idea as well (it came up on the LAU
> thread about the "ultimate modular synth" before I even wrote a single
> line of code).  Noone's really needed it yet, so I havn't bothered.

Dare I say <soft voice>"I need it"</soft voice>?
> Ahem.  Om is one of the most rigorously realtime safe and performance
> audited (in the audio thread anyway) linux audio apps I know of.  The
> version in CVS is DRAMATICALLY more efficient at mixing down ports and
> whatnot than 0.2.0, but Om's overhead compared to the plugins is so
> insignificant it matters little.

Ok. I'm looking forward to trying out the new stuff. And I realize that 
slow or poorly written plugins may eat it all up...

> If you can crash the 0.2.0 engine, you're more
> clever than I (and I want to know how).

BTW: I never had a crash (like in 
core-dump-freeze-or-exit-without-warning) in om. Still the ride feels a 
bit bumpy at times .-)

From where I stand some aspects of om is as rock solid as you mention. 
But things like the communication issues are still an anoyance, and a 
growing one when you stress the system harder.

So when I program patches om performs very nice. I have one or maybe two 
patches open, and everything (mostly) goes well. But I need to bring a 
complete setup that will restore at least a handful of sounds every 
single time to the stage.

> Don't go slamming a
> project because CVS is unstable, that's beyond stupid.

How nicely put :-)

> BTW, you have just implicitly volunteered to thoroughly test the next
> release. :)

Sure, sure!!!

> Anyway, I don't know what the point of this diatribe is.

It wasn't meant as a rant. I was desperate, and though I'd share my 
frustration with you.

>  Need hold pedal support?  Mention it (like you did
> before).  It'll take me less than an hour to do that, it's not a big
> deal at all.

Ok, I'll be looking forward to that :-)

> What did YOU do today? 

I spend most of the day trying to put my new sounds into lash sessions 
that would restore correctly. I managed one, and had to go to the 
rehearsal one tune short...

--
peace, love & harmony
Atte

http://www.atte.dk