9 Dec
2002
9 Dec
'02
12:35 p.m.
On Mon, Dec 09, 2002 at 04:52:48PM +0100, David Olofson wrote:
Hmm... Which one? (What did I mix up *this* time? ;-)
You example had (unless I misunderstood) an output from an instrument
feedback into itsself.
Well, its is, but...
Why? You can accept that there will be some extra latency in one section
of the loop and it doesn't usually matter. Granted its not ideal, but
blockless processing /really/ isn't practical on CPUs yet c.f. OT
discussion.
That's the feedback loop problem. As long as the
host runs
plugins in the correct order, you'll never see this unless you
*actually* have loops in your network.
Like in your example ;) Hmm.. I can
see why this is tempting, it avoids the wrapping
problem, among other things. Are you sure its not better that way?
Wrapping is not a problem, so why avoid it? :-) Easy. :-) It's wrapped in API macros, so you
won't have to see any of
that (rather trivial) integer arithmetics, unless you're doing weird
stuff with events.
OK, that would remove my worries.
OTOH, is it really *uselful* to support larger buffers
than 32768
frames...?
Probably not, but I dont think its useful to express timestamps in 16bit
chunks. You either throw away another 16bits or your data would loose
32bit alignment.
And, having 32 bits might fool develpers of sequencers
and other
"long time frame aware" devices into believing that you don't have to
worry about wrapping *at all* - which is not true. Use 32 bit
Yes, this has happened to me in an oscilator inplementation, which is why
I'm concerned :)
Ouch. Changing
the buffer size sounds messy and inefficient.
(Still, VST hosts do it all the time, since automation "events" are
still passed through function calls... *heh*)
Anyway, even with a timestamped event system, this is the *only* way
you can handle feedback loops. And what's so messy about it? Less frames/cycle
means you can use the
standard buffers, and timestamps not being buffer relative means you
don't have to do anything extra at all with events. Just loop over
OK, not messy, just supprising, as in "all I did was place a plugin in
here and suddenly the cpu cost went up three times, your plugin is
broken"
- Steve