On Sat, Nov 15, 2003 at 05:12:45PM +0000, James Stone wrote: > On Tue, Nov 11, 2003 at 09:13:58PM +0000, James Stone wrote: > > Hello everyone. > > > > I have a problem with midi timing.. I think I have set up enhanced rtc > > correctly and low latency patch on kernel 2.4.20. > > > > When I drive hydrogen (or even the inbuilt soundfont player on my > > SBLive) with seq24 or ardour, there is a noticable variation in midi > > timing. This was tested by using a run of closed hihats. When I play the > > sequence back, the hihats are grouped in batches rather than being > > evenly spaced. This was noticable when running as root and when using > > alsa and (to a lesser extent) jack. The midi connection is via alsa. > > > > Any hints on what I should do? > > > > James > > Just to reply to myself, > > I solved the problem: > > I needed to install the snd-rtctimer for alsa. This required a patch to > the kernel RTC (patch included with ALSA but also needed a tweak. see: > > http://www.geocrawler.com/archives/3/12349/2001/7/0/6299315/ > > ) > > After that, snd-rtctimer built okay. Then I added the following to > modules.conf: > > options snd-timer snd_timer_limit=2 > options snd-seq snd_seq_default_timer_resolution=2000 snd_seq_default_timer=1 > options snd-rtctimer rtctimer_freq=2048 > alias snd-timer-1 snd-rtctimer > > Now, midi timing is sorted (at least for muse when running as root so it > can access the RTC.. seq24 doesn't seem to be quite there yet in my > experience). Just a further note.. Needed to apply the variable frequency kernel scheduling patch and set the frequency to 1000Hz and now the timing problem with seq24 is solved. James
