[pulseaudio-discuss] 'clicks' in audio and rtp troubles

Lennart Poettering lennart at poettering.net
Mon May 28 05:23:28 PDT 2007

On Mon, 28.05.07 13:54, joysn at gmx.net (joysn at gmx.net) wrote:

> On Mon, May 28, 2007 at 12:15:28PM +0200, Lennart Poettering wrote:
> > On Mon, 28.05.07 01:03, joysn at gmx.net (joysn at gmx.net) wrote:
> > 
> > > one thing is, not specific to audio output as it also occurs when no
> > > application plays music through pa: i can hear a click every few seconds
> > > but cannot figure out from where it comes. 
> > 
> > Could you please run PA with "-vv" on the command line? Is anything
> > printed to STDOUT when these clicks happen?
> on every click the following line is printed:
> module-alsa-source.c: *** ALSA-XRUN (capture) ***

Are you sure you have set up realtime scheduling correctly? (i.e. have
made yourself member of either the group "rt-pulse" or "realtime" --
the group name depends on the installation. Debian and PA 0.9.6 and
above use "rt-pulse". PA 0.9.5 on non-Debian machines use "realtime".)

> but when i try to access the stream from mac os x and vlc or vlc from
> localhost (when configured with loop=1) then i could not connect to it. with 
> tcpdump i see lots of packets go to

Last time I looked VLC is unable to pick up SAP announcements from
anything but the global SAP mcast group This is a
limitation in VLC. Since we don't want to broadcast our RTP sessions
all over the Internet we use the link-local group instead
by default.

> 13:47:19.281686 IP joysn.local.32809 > UDP, length 1292
> 13:47:19.281696 IP joysn.local.32809 > UDP, length 1292
> 13:47:19.281703 IP joysn.local.32809 > UDP, length
> 1292

Please note that we do not implement RTSP. Only RTP with SAP/SDP. RTSP
has been on my TODO list, but I haven't worked on it yet.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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