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

[Chris Joelly]

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) ***

> > the second thing is that i could not use a rtp sink. maybe i dont
> > understand the rtp modules correct.
> > with the rtp (rtsp/sap/...) sink i can output audio to a rtp multicast
> > group and play it on another host with a rtp capable audioplayer, e.g.
> > vlc or mplayer on an mac os x machine? is this right? if so, how should
> > i configure and use that rtp sink?
> 
> There is no such a thing as an "RTP sink" in PA. You may however
> create a NULL sink and slave an rtp source output to the monitor
> source that belongs to it. See FAQ #22.

i thought i understand things wrong ;-)

> http://pulseaudio.org/wiki/FAQ

ok. i read this faq and also the slides from your presentation of
pulseaudio... this happens when i create the null sink:

ient.c: created 0 "UNIX socket client"
sink.c: created 3 "rtp" with sample spec "s16le 2ch 44100Hz"
source.c: created 6 "rtp.monitor" with sample spec "s16le 2ch 44100Hz"
core-subscribe.c: dropped redundant event.
core-subscribe.c: dropped redundant event.
core-subscribe.c: dropped redundant event.
core-subscribe.c: dropped redundant event.
core-subscribe.c: dropped redundant event.
module.c: Loaded "module-null-sink" (index: #19; argument: "sink_name=rtp").
module-alsa-source.c: *** ALSA-XRUN (capture) ***
module-alsa-source.c: *** ALSA-XRUN (capture) ***
module-alsa-source.c: *** ALSA-XRUN (capture) ***
source-output.c: created 1 "RTP Monitor Stream" on rtp.monitor with sample spec s16be 2ch 44100Hz
memblockq.c: memblockq requested: maxlength=174080, tlength=174080, base=4, prebuf=1, minreq=0
memblockq.c: memblockq sanitized: maxlength=174080, tlength=174080, base=4, prebuf=4, minreq=1
module-rtp-send.c: RTP stream initialized with mtu 1280 on 225.0.0.1:554, SSRC=0x67d3c944, payload=10, initial sequence #13574
module-rtp-send.c: SDP-Data:
module-rtp-send.c: v=0
module-rtp-send.c: o=chris 3389338332 0 IN IP4 192.168.0.3
module-rtp-send.c: s=PulseAudio RTP Stream on joysn.chello.at
module-rtp-send.c: c=IN IP4 225.0.0.1
module-rtp-send.c: t=3389338332 0
module-rtp-send.c: a=recvonly
module-rtp-send.c: m=audio 554 RTP/AVP 10
module-rtp-send.c: a=rtpmap:10 L16/44100/2
module-rtp-send.c: a=type:broadcast
module-rtp-send.c: modules/rtp/module-rtp-send.c: EOF
module.c: Loaded "module-rtp-send" (index: #20; argument: "source=rtp.monitor destination=225.0.0.1 port=554").
module-alsa-source.c: *** ALSA-XRUN (capture) ***
module-alsa-source.c: *** ALSA-XRUN (capture) ***
module-alsa-source.c: *** ALSA-XRUN (capture) ***
module-alsa-source.c: *** ALSA-XRUN (capture) ***
sink-input.c: created 19 "sample:x11-bell" on rtp with sample spec s16le1ch 44100Hz
sink-input.c: created 20 "sample:x11-bell" on rtp with sample spec s16le1ch 44100Hz
sink-input.c: created 21 "sample:x11-bell" on rtp with sample spec s16le1ch 44100Hz
memblock.c: Memory block too large for pool: 17640 > 16376
lots of *clicks* ;-)

then i connect amarok to pulseaudio:

module-volume-restore.c: Restoring volume for<pulsecore/protocol-native.c$amarokapp>
module-volume-restore.c: Restoring sink for<pulsecore/protocol-native.c$amarokapp>
sink-input.c: created 30 "audio stream" on rtp with sample spec s16le2ch 44100Hz
memblock.c: Memory block too large for pool: 1048576 > 16376
memblockq.c: memblockq requested: maxlength=176400, tlength=158760, base=4, prebuf=79380, minreq=15876
memblockq.c: memblockq sanitized: maxlength=176400, tlength=158760, base=4, prebuf=79380, minreq=15876
module-alsa-source.c: *** ALSA-XRUN (capture) ***
jep, there's one more *click* :-)

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 225.0.0.1:

13:47:19.281686 IP joysn.local.32809 > 225.0.0.1.rtsp: UDP, length 1292
13:47:19.281696 IP joysn.local.32809 > 225.0.0.1.rtsp: UDP, length 1292
13:47:19.281703 IP joysn.local.32809 > 225.0.0.1.rtsp: UDP, length 1292

vlc from localhost tells me (tried with rtsp and rtp):

[00000291] live555 demuxer error: Failed to connect with rtsp://225.0.0.1
[00000289] main input error: no suitable access module for `rtsp://225.0.0.1'
[00000280] main playlist: nothing to play
[00000304] access_udp access error: cannot open socket
[00000302] main input error: no suitable access module for `udp://@225.0.0.2:554'
[00000280] main playlist: nothing to play signal 2 received, terminating vlc - do it again in case it gets stuck
[00000280] main playlist: stopping playback

i think that this problem resides on the client side of the steam, but i
can not figure it out...

Joysn