Paul Davis wrote:
> >Hi, I'm developing an 8 channel recorder based on alsa0.9.0beta10 and a > >Terratec EWS88mt sound card. > >I'm now using a 2.4.18 kernel with the Andrew Morton patches applied. I > >really want to be able to record/playback at the full 96k 24bits on all > >8 channels simultaneously, but I need absolutely no under/overruns. > >Currently, as I try to up the bandwidth requirements I get xruns > >occurring more and more frequently; I'm not even sure if I can guarantee > >a maximum, before the onset of xruns, although 16bit 44.1 may well be > >okay. > > > >I don't care about other system processes, so I've set the record and > >playback threads to SCHED_FIFO prio 99 (although I don't really know if > >this is the right thing to do!) > > > >Is there anything I can do/change/not do to eliminate xruns altogether? > > You cannot eliminate xruns altogether. xruns are caused either by OS > scheduling delay, or by processor load. I trust that you are not > trying to read/write from/to disk from the same thread as you are > handling audio in ... > > Ardour (http://ardour.sf.net) records 24 channels with 32 bit samples > with no xruns. Perhaps you are not familiar with this project. It uses > JACK (http://jackit.sf.net) as its underlying audio engine, which in > turn uses ALSA. > > --p Er, actually I am doing it all in a single thread, I guess this is not a good idea. I will modify things and see how I go! I looked at Ardour at the beginning of last year, and thought it looked very good, although I must confess I never got it to record. The JACK part doesn't ring any bells, I will take a look. The reason I'm writing my own, far simpler, 8 track recorder, is because I wanted to do it for myself, being an ex Sound Engineer turned Computer programmer. I did look at the code for Ardour, but it was quite involved, and I didn't have the time then to get to grips with it. I actually ended up looking at how aplay works, which is how I've ended up with a single thread!! Thanks, Fergus ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ********************************************************************** _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
