12:06 am, 14 Nov 04
sound skips on linux ppc 2.6
I finally figured out why my sound was so flaky: apparently ALSA's emulation of OSS sucks in some way. The symptoms were that if I were playing music in XMMS and I wiggled the mouse around furiously (note: not even dragging a window, just causing X to send a lot of events), the audio would skip.
Once I had ogg123 -d alsa09 foo.ogg producing sound, reconfiguring gstreamer to use ALSA instead of OSS means that at least Rhythmbox (which I haven't really used in the past, but I dug up for the purposes of testing) works. XMMS, even with ALSA output, is still unreliable, but at one point I saw someone claim on a mailing list that it's some fundamental brokenness of XMMS.
Now if I can only figure out why it powers off instead of going to sleep, I'll have a computer that has technological innovation rivalling something out of the mid-nineties!
Once I had ogg123 -d alsa09 foo.ogg producing sound, reconfiguring gstreamer to use ALSA instead of OSS means that at least Rhythmbox (which I haven't really used in the past, but I dug up for the purposes of testing) works. XMMS, even with ALSA output, is still unreliable, but at one point I saw someone claim on a mailing list that it's some fundamental brokenness of XMMS.
Now if I can only figure out why it powers off instead of going to sleep, I'll have a computer that has technological innovation rivalling something out of the mid-nineties!
kernel
what kernel are you using? I had a similar power problem with my iBook until one of the later 2.6.8 revisions. I don't know what ppc you are using, but this guy's config files may be a good reference. The sound on my iBook works great except for being a little too quiet.Re: kernel
2.6.8.1, and my sound is fine except a little too loud. :)My theory is that the visualisation delay is causing XMMS to get out of sync with the kernel in filling the output buffers. (This is x86 linux, but I imagine the issue is generally applicable.)
I suspect your issue with the OSS emulation is possibly more related to interrupt load than, necessarily, X events. Although I suppose the context switches from all those X events might not be helping. In any event avoiding emulation layers (eg, ALSA emulating OSS) where it is feasible is generally a good thing.
Ewen
(First seen on Nat Friedman's blog.)
I belive it can use all the xmms skins, and i believe even some of the plugins.