Synchronized playback via icecast, mpd or something else?

Message

Mikos · Post by **Mikos** » Wed Dec 08, 2004 12:36 am

Hello,
I would like to know if there is some way how to play music over local LAN in sync. For example if I have one PC in one room and second PC in another room, etc. I was thinking about icecast or mpd, but then I read on forums that the playback is not in sync, that there is some lag.

Or is it possible to play MP3 and OGG music via LAN (on more than 2 computers) without delay using icecast or mpd?

Server will be running Gentoo linux but clients will be both Windows and Linux. It would be best if the player on Windows clients could be WinAmp.

EDIT: Another question - what is pros and cons of icecast vs. mpd? What is better for which purposes?

Mikos · Post by **Mikos** » Thu Dec 09, 2004 9:22 pm

Is there really nobody who knows? I think this synchronised playback of LAN audio broadcasts is really important thing...

JazzSax006 · Post by **JazzSax006** » Fri Dec 10, 2004 4:06 am

My understanding is that this is impossible to accomplish given current hardware. I had wanted to do the same thing, but here are the problems you run into:

-Network latency (couple milliseconds?)
-Soundcard latency (20 - 60 milliseconds?)
-Processing/Harddisk latency (???)

My numbers are probably off, but the idea being that all of this latency adds up and is near impossible to calculate in order to synchronize output. The human brain can recognize audio delays greater than 1 millisecond, but groups delays of between 1 and 50 milliseconds of the same sound together as timbre of the original sound. Anything greater than a 50ms delay is heard as an echo. So in other words, you would have to ensure all of the sound is being processed AND outputted within 50ms synch on all of the speakers. Also, you would have to take into account the distance between all of the speaker sources and the fact that sound moves at a relatively slow pace (compared to light, etc.) and this would also introduce more delay. Enough rambling...if you'd like to read more, google the subject, or read the following link...(some of my info is ripped from it

)

http://www.moultonlabs.com/articles/93micear.htm

JazzSax006 · Post by **JazzSax006** » Fri Dec 10, 2004 4:13 am

Just noticed your additional question about icecast vs mpd. I would suggest icecast if you want to stream your music over the net so you or your friends can listen to it from an outside net connection. If all you want to do is play music from one box but control it via your lan (for instance, a pc lacking a monitor but hooked up to a stereo) then mpd is the tool for you. I live in an apartment with 3 other roomies and have a htpc with mpd hooked up out in our living room. It's nice because all of us have simultaneous control over the playlist and can add our favorite songs (or remove our roomy's lousy songs...heh) from our rooms.