Nick, Start working with Jack. I can run my hardware at 1.3mS latency and lots of stability. Mark On Tue, 2003-04-01 at 19:57, Nick wrote: > > I am writing audio applications that are real-time. > I had been using Port Audio which is really very good, even without root > priviledges, it does a very good job. I want to support other sound > drivers, in case someone doesn't have Port Audio or can't get it to > work. > > I have just built my ALSA driver, it works ok, but I am getting terrible > latency problems and buffer underruns. The thing is it is a real-time > application, it must get audio to the card as soon as possible. Why is > it that OSS with Port Audio works so well, and my ALSA setup is > suffering? > > Even if I set the frame rate higher (the number of frames to the card) I > still get buffer underruns. I am talking maybe 70 milliseconds now. This > is sad, because I know with DirectX I can get about 35 ms timing with it > on this machine.With ASIO I have done better than that. > > Even running as root and scheduling the app to real-time priority (50) I > get buffer underruns. So, something must not be right with my setup. > > I have tried setting the frames written to all sorts of latencies, and > it does reduce the drop outs, but I am still getting them. I tried > buffering the sound and dropping it in blocks, but it wasn't working > correctly. This is a bit disappointing so far. > > Is there something I need to do to ALSA to get near real-time > performance from it? I have heard people mention patching their kernel > for low latency. I have Jack but I have not started working with it yet. > Should I dump ALSA and just go for Jack? Is there something I need to do > to my kernel to get better performance? I would get Planet CCRMA if it > supported my OS, but it doesn't, so I have to tweak my box manually. > > Thanks > > > > > > -- > Nick <nicktsocanos@xxxxxxxxxxx> >
