On Mon, 2005-06-27 at 20:31 -0700, [EMAIL PROTECTED] wrote: > > From: Lee Revell <[EMAIL PROTECTED]> > > Date: Mon, 27 Jun 2005 22:30:11 -0400 > > > > On Mon, 2005-06-27 at 19:03 -0700, [EMAIL PROTECTED] wrote: > > > > With kernel 2.6.12 + "[PATCH] ehci-hcd - fix page pointer allocation in > > > > itd_patch()"), using jackd in realtime mode at 44.1kHz with 64 > > > > frames/period and 4 periods/buffer, I get a stream of xruns of about > > > > 0.020 ms, several per second. > > > > > > In USB, one frame == 1 msec. Most EHCI silicon using the 2.6.12 code > > > will get unhappy with 256 msec per ISO URB, so I hope you're using > > > "frame" without a necessary adjective ... ;) > > > > > > > "frame" = audio frame (4 bytes with S16LE). > > "USB frame" = 1 msec > > No. "frame" == ambiguous. This message is on a USB list, where the > no-adjective version means "USB frame". It's also cross-posted to > a list where the no-adjective version means something very different. > > The only solution that removes ambiguity for _everyone_ is to ensure > that such words never appear without an adjective. >
OK, makes sense. So what the poster was saying was that if he uses 64 audio frames per period, which at 44.1KHz requires the audio interface to deliver a chink of data every ~1.4ms, he gets periodic xruns, IOW the audio interface is not able to do that. If he uses 128, he gets no xruns, so he's getting a chunk of data every 2.8ms, but it's corrupted, hence the crackling. Lee ------------------------------------------------------- SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from IBM. Find simple to follow Roadmaps, straightforward articles, informative Webcasts and more! Get everything you need to get up to speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
