On Wed, Feb 20, 2008 at 05:15:39PM +0200, Tanu Kaskinen wrote: > On Wed, Feb 20, 2008 at 12:00:22PM +0100, CJ van den Berg wrote: > > RTP doesn't provide any kind of synchronisation, so the different > > machines will definitely drift. This is a much bigger problem that the > > different latencies. At least the latencies are constant. And yes, it > > will be very annoying. > > > > > any experience with this? > > > > I've tried it once between two rooms at opposite ends of my house. It > > started out with a slight reverb effect, which was pretty acceptable. > > But after about 3-5 minutes it was far enough out of sync that turned > > into an annoying echo effect. > > Why does that happen? The source machine is pushing stuff to > the network at rate R1 and the receivers can do nothing > about it. Also the soundcard pulls audio from module-rtp-rcv > at rate R2. It's clearly wrong to assume that either clock > would actually tick at the rate it claims to tick, let alone > assuming that both would be accurate. So there must > resampling that compensates the difference between R1 and > R2. R1 is the same in all receivers, so if rate compensation > is done, the only thing that can cause sync problems between > receivers is their different internal latencies. > > Doesn't module-rtp-recv do the resampling after all, or what > part have I understood wrong? TBO, I wasn't aware that module-rtp-recv was supposed to be doing rate compensation resampling. If it does, then my observations must have some other explanation. -- CJ van den Berg mailto:cj at vdbonline.com xmpp:cj at vdbonline.com -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: Digital signature URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20080220/495ee517/attachment.pgp>
