Re: [LAU] Linux systems as a distributed speaker array

On Tue, Feb 10, 2009 at 10:25:34AM +1100, James Cameron wrote: [Poor man's delay line] I have hacked jack.udp to use IPv6 Multicast instead of unicast. You'd simply connect your player (mplayer, qmmp, whatever) to the sending jack.udp and every other running instance on the LAN would get the broadcasted data within let's say 256 samples. Since data is only sent once, bandwidth consumption is very low. The buffersize is quite small, this system works fine over here for jamming in different rooms of the same building (must share the same LAN). I wouldn't claim sample accuracy, but the audible result should be good. If you want to give it a whirl, get the source here: http://cluster.inf-ra.uni-jena.de/~adi/jack-udpv6.tar.bz2 How to use: You don't provide hostnames anymore, the data is simply sent to a fixed link local multicast address. Run the sender: jack.udp -b BUFSIZ send where BUFSIZ is your desired FIFO size. Without realtime privs, I got good results with BUFSIZ = 2*periodsize. You'd need to try a little to get the best buffer size. All receivers start jack.udp -b BUFSIZ(+1) recv That's it. They automatically subscribe to the multicast group, receive the data and offer it as a jack output port. I got good results with BUFSIZ+1, but jack.udp would inform you on buffer over/underflow. If so, increase the buffer size or add realtime prio. If you have multiple network interfaces, jack.udp would need to know which one to use. Since the code is proof-of-concept, there's currently no command line option for this. If you need it, I could add it, or you edit nettools.c, look for "eth0" in the comment and specify your network interface card number. You can get the right value from "ip a s": 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 Here, "2" would be the right value. Once again, you only need that if you have more than one NIC. HTH -- mail: adi(a)thur.de http://adi.thur.de PGP/GPG: key via keyserver Die Klassenarbeit ist versaut, wenn einer dir den Spicker klaut