Arch Linux

buttons

Member

From: NJ, USA

Registered: 2007-08-04

Posts: 620

PulseAudio multicast network sound changes playback speed randomly

Let's get this out of the way; at least on my desktop (where I would like the music to play) I have no problems with pulseaudio.

I set up pulse and mpd-pulse on my server, which is where all my music is.  As I hate the quality of icecast, I decided to set up networked sound, so that any playback from the server plays back everywhere else.  I'd like this to be more than just a client-server operation *if possible*, as I have a lot of computers and playback on all of them at the same time would be quite a treat.  So, multicast seemed like the way to go.

I got this set up using the following code snippets in my /etc/pulse/system.pa:

Server:
load-module module-null-sink sink_name=rtp
load-module module-rtp-send source=rtp.monitor rate=44100
set-default-sink rtp

Client:
load-module module-rtp-recv

With the appropriate network modules loaded, this is fine.  It works.  Kinda.  The sound quality is even good.

However, the rate of playback changes randomly.  It's like the music is driving around me in circles, changing acceleration at a whim.  I might be listening to mice one moment and kelly clarkson might be singing bass the next.  That's a slight exaggeration, but you get the idea.

Does anyone have this working?

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drelyn86

Member

From: Indianapolis, IN

Registered: 2009-04-10

Posts: 80

Re: PulseAudio multicast network sound changes playback speed randomly

I was just experimenting with this over the weekend, and got the same results.

It's because of the complete nature of multicast and UDP. It's an unreliable protocol. There is no communication between client and server on which packets are being successfully transmitted.

I had much better results by using MPD, and setting up multiple pulse outputs in the mpd.conf file. There wasn't nearly as much variation... but there was a slight latency that was noticeable. However, if your speakers are completely isolated from eachother (where you wouldn't actually hear from more than one system at a time), that wouldn't be a problem at all.

My next little project might be trying to send simultaneous MPC signals to my MPD servers... wondering if that might get the timing more precise.

buttons

Member

From: NJ, USA

Registered: 2007-08-04

Posts: 620

Re: PulseAudio multicast network sound changes playback speed randomly

Ahhh...dammit.  I just tested the normal client/server networked audio, and it works fine as you said.

If you actually get things to work, kindly report back

Last edited by buttons (2009-05-26 21:51:35)

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Cthulhu For President!