On 9/20/05, Matt Garman <[EMAIL PROTECTED]> wrote: > > I installed jack (jack-audio-connection-kit), and configured it, as > far as I can tell, correctly. At least I can get multiple audio > streams multiplexed together. > > However, the performance leaves something to be desired: it is > *extremely* prone to skipping, if my system is under any kind of > load. For example, doing an "emerge search <package>" will usually > cause my XMMS playback to skip. *Moving a window* will almost > always cause a skip---not just skip, but freeze for the whole time > the window is being moved. Even worse, whenever the screensaver > comes on, the player skips. And while the screensaver is active, > the music playback will regularly skip every couple seconds. The > kicker? My screensaver is just a blank screen! > > I'd like to think that my system is powerful enough to do "normal" > desktop use without skipping: Athlon XP 2500, 1 GB RAM. > > Any thoughts as to why the jack performance is so shoddy? > > Thanks! > Matt > > -- > Matt Garman > email at: http://raw-sewage.net/index.php?file=email > -- > gentoo-user@gentoo.org mailing list > >
Matt, I'm very sorry but I somehow never saw this thread. Please accept my apologies. Did you get this working better? Anyway, I'd say that your machine is certainly fast enough to do good audio work, barring some specific chipset or driver issue which most likely won't be the case. In my experience there are usually just a few things required to get this working. 1) First, let's determine whether you need a new kernel. su to root and run Jack and some simple Jack apps. I'd recommend alsaplayer since it's simple, small and very stable: (Note - this is best done through QJackCtl, but you can do it at the command line if you want.) Choose latency numbers that make sense for your card and your needs. I run at 128/2: jackd -R -dalsa -r44100 -dhw -p128 -n2 Then with Jack running run alsaplayer alsaplayer -o jack Tell alsaplayer to play a wave file or play a CD for a better, longer test. Any skipping? If you have skipping at this point then you most likely need a real-time kernel. My 32-bit machines do not. They run fine with gentoo-sources, but my amd64 doesn't run well and needed a new realtime kernel to work right. 2) Assuming that your tests as root go well, then emerge realtime-lsm. This may require a new kernel if you don't have the right Linux Securities stuff enabled: [ ] Enable access key retention support [*] Enable different security models [ ] Socket and Networking Security Hooks <M> Default Linux Capabilities < > Root Plug Support < > BSD Secure Levels [ ] NSA SELinux Support Reboot into your new kernel if necessary, emerge realtime-lsm at this point. 3) Create a group for realtime access. Here's mine: lightning linux # cat /etc/group | grep realtime realtime:x:600:mark lightning linux # 4) Modprobe realtime at the command line: modprobe realtime gid=600 any=1 5) Assuming this all goes well, redo your tests with alsaplayer and make sure it's working as a user. Enabling realtime operation thorugh realtime-lsm is CRITICAL to making this work well over time. For instance this morning I'm rebuilding glibc as part of an emerge sync / emerge world operation. At the same time I'm doing email on the web as well as playing music with Aqualung on my AMD64 machine. Jack is running at 128/2 and I can go for hours without any xruns. True, we are still working bugs out of the newest kernel (2.6.14-rc3-rt10 as of this morning) but things are starting to work pretty well even on AMD64. My gentoo-sources 32-bit machines can go for days with out an xrun. (Granted, very good RME sound cards that cost as much as the machine are being used....) Hope this helps. Write back if you want or need more info. Cheers, Mark -- gentoo-user@gentoo.org mailing list
