Re: What Parts of Linux Audio Simply Work Great? (was Re: [linux-audio-dev] Best-performing Linux-friendly MIDI interfaces?)

From: Florian Schmidt <mista.tapas@email-addr-hidden>
Date: Thu Jun 16 2005 - 23:57:51 EEST

On Thu, 16 Jun 2005 20:20:41 +0200
fons adriaensen <fons.adriaensen@email-addr-hidden> wrote:

> > The price for this is afaik an extra period worth of latency. I'm not
> > sure this is the way to go. Sure it makes handling of devices easier
> > that do not generate irq's like pci soundcards do (all this USB and
> > IEEE1394 stuff), but isn't the price too high?
>
> Why should this take a extra period of latency ?

Ah, i remembered slightly incorrectly. Thanks Paul, for setting me
straight in #ardour. The thing is that the DLL based client thread
wakeup has the ever so slight possibility to do its thing too early.
Thus coreaudio waits a bit more (the "safety offset").

It seems this safety offset is driver specific but usually ranges from
64 to 32 frames (i have no definite source for this, just a bit of
googling). And with a sufficiently low period size used this accounts
for pretty much an extra period of latency..

Flo

-- 
Palimm Palimm!
http://affenbande.org/~tapas/
Received on Fri Jun 17 00:15:14 2005

This archive was generated by hypermail 2.1.8 : Fri Jun 17 2005 - 00:15:14 EEST