On Fri, 24 Jan 2003, Kjetil S. Matheussen wrote: >> What does "cat /proc/asound/card0/pcm0[cp]/sub0/[hs]w_params" output > I'm at work now, and we ~only have delta cards. At home I use a built-in > sound-card on an nforce chipset. But I get nearly the same good > performance in pd here as at home. So here is delta44 parameters:
Could you also send an output of pcm0[cp]/sub0/status...? Anyway, this is very good info. > kjetism@hensten /proc/asound/card0/pcm0c/sub0 $ more hw_params [...] > period_size: 64 > buffer_size: 1728 So I guess this explains a lot. This equals to running jackd with "-p 64 -n 27" (and not as root or otherwise it will throw clients out if they miss one 64 frame deadline). I'm quite sure you get much more reliable performance this way, although JACK doesn't take advantage of multip-period buffer configurations very well. And this has its reasons. With a setup like shown above, you either get a huge latency (64*1728/44100*1000=2500ms), or you get latency jitter (latency varies between 1.45ms->2500ms). Both are something we'd _really_ want to avoid. Because of the above reasons, JACK is designed for two or three period operation (-n 2 or -n 3). This way we can achieve both low latency and avoid latency jitter. We could improve reliability by sacrificing one or both of these goals, but for many of the use scenarios we are aiming at, this is simply not acceptable. -- http://www.eca.cx Audio software for Linux!