For a few weeks I've been using PulseAudio network tunneling over wifi. I've noticed that on a very regular interval the audio stutters for a few seconds. I've been watching network traffic in KSysGuard, and I noticed that the transmit rate is usually about 200 KB/sec, but when the audio stutters, the transfer rate drops slightly. When that's the only thing going on on my network, I can observe this happening at a completely regular interval.
I finally figured out that it's caused by my laptop's wireless card scanning for other networks. I can make it stutter in exactly the same way on command by running "iwlist scan". My laptop has an "Intel Corporation PRO/Wireless 4965 AG" network card, and it uses the iwl4965 driver. Now my laptop very rarely moves anywhere, and it is always on my home wifi network, so I don't need it to scan for other networks. If I could simply disable scanning on my laptop, it wouldn't stutter anymore. Of course, more buffering in PulseAudio would help a little, but I think all it would do is cause it to stutter a bit less often. Eventually the stuttering would cause the buffer to empty, because it can't fill faster than audio is being played. So it could stutter less often, for a longer period of time, but it would still end up stuttering. I've been googling around, trying to find a way to adjust the scan interval, but I haven't found anything yet. I'm not sure if it's controlled by wpa_supplicant or the driver. I've also seen that some cards seem to support "background scanning" and others "progressive scanning", and I don't know if one of those would mitigate it, or if my card already does one of them. Anyway, for anyone else who is having stuttering, if you're on wireless, one cause of it is almost surely the scan interval. Find a way to fix that and you may solve it. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to pulseaudio in Ubuntu. https://bugs.launchpad.net/bugs/273742 Title: Pulseaudio over wifi stutters horribly Status in PulseAudio sound server: New Status in “pulseaudio” package in Ubuntu: Confirmed Bug description: When streaming audio data via the local pulseaudio sound server of my laptop over wifi to my server, the sound lags a lot and mainly consists of "skippings". Starting an application, e.g. totem, via "PULSE_SERVER=<my_server> totem" from the shell, everything works perfectly. So it doesn't seem to be a problem with my wifi, but probably with the audio buffers of the local pulseaudio server (i.e. when tunneling streams via the local sound server). Happened on Hardy and still happens on Intrepid, and now on Jaunty. To manage notifications about this bug go to: https://bugs.launchpad.net/pulseaudio/+bug/273742/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
