8 Nov
2007
8 Nov
'07
9:53 a.m.
David Olofson <david(a)olofson.net> writes:
in zynadd, voices are not poliphony voices (they are called notes there)
but voice modules. zynadd is semi modular synth.
no idea what you mean by regroup, for each parameter, group or message
there are internal fixed size structures.
Point is whether arbitrary and fixed chunk allocators be in one
extension. I tend to think that they should be separate because
algorythms behind them are quite different and host may choose to
implement only one of them. Also most lock free algorithms are patented
so this can be point of host supporting only one feature set.
On Thursday 08 November 2007, Nedko Arnaudov wrote:
[...]
There is point when you have several dynparam plugins that all user
dynparam helper library requesting same sized chunks.
The point is that some plugins need *realtime
safe* memory
allocation.
Well, yes; that part is quite obvious.
What I meant was, if all the host provides is a pool of uniformly
sized chunks that are allocated when the plugin is initialized, there
doesn't seem to be much point in implementing it on the host side.
The naïve host side implementatio would add exactly nothing, compared
to plugins just allocating their own pools during initialization. A proper real time manager, with arbitrary chunk
sizes, would be more
motivated, as it adds functionality that plugins can't implement
internally; namely a shared memory pool.
I'm not against it but I dont see use of it for lv2 zyn plugins /
lv2dynparam / zynjacku. Except for enum value strings that I plan to
make fixed (runtime) max size.
I
need this functionality for lv2zynadd plugin (like arbitrary voices
count allocation)
The "standard" solution is to pre-allocate and pre-initialize voice
structures for a fixed maximum polyphony.
Obviously, this becomes troublesome with modular synths and the like,
where the "voice structure" doesn't have a fixed size. One solution is to allocate the voice pool as a
response to "program
change" events. Of course, this makes the "programe change" operation
non real time safe, but it usually is anyway, due to samples being
loaded from disk and stuff. Many systems, both hardware and software,
are based entirely on the idea that patch loading is part of
setup/initialization, as that is often the only practical solution.
It's really only entirely ROM based synths (or "small fixed sample
set", in the case of software), virtual analog synths and the like
that *can* implement real time safe "program change" at all.
One of ultimate goals of zynjacku is to make this happen with zyn
plugins. Patch loading involves lv2dynparam communication that is
realtime safe. It make take some time during which synth "parameters"
will be in intermediate state, but this will depend on cpu power and
preallocation size. Things that user has control of.
and for
lv2dynparam plugin library internal
operation too.
It needs to "regroup" internally as a response to certain parameter
changes? There were
rumors in #lad that such functionality may be useful
without lv2dynparam extension.
Well, yes; real time safe dynamic memory management can make life a
lot easier for some types of plugins, and/or reduce memory
requirements by having a shared pool. However, I think it needs to be
more generic than just a pool of fixed size chunks for the "shared
pool" part to be viable. [...]
The point is how should you define that feature A depends on feature
B. LV2 in its current state, to my knowledge, does not treat this as
bug.
--
Nedko Arnaudov <GnuPG KeyID: DE1716B0>
That reminds me that LV2 may need a way to
specify optional features
that interdepend. I.e. features (extensions) A and B are both
optional but if A is provided B is required. Of course plugin can
check this explicitly on instantiate and refuse to use feature, but
I'm not sure how vital is such approach.
Haven't really thought about this... Isn't it just a matter of plugins
and hosts listing *all* extensions? I mean, if you provide or ask for
this feature A, but not feature B, you have a bug. An automatic
validation tool would trap this right away - but of course,
someone/something has to tell the *tool* about these extension
interdependencies...