Folderol: > Giso Grimm <gg3137@xxxxxxxxx> wrote: ... > > b) own protocol, multiple OSHw, master clock: > > > > Master Clock > > Host sound card > > || > > jackd <===> OSHw > > <===> OSHw > > <===> OSHw ... > It appears there is a software suite for the 'other' OSs that can > manage 16 channels of 48k over the Internet (not just a LAN) provided > you have an upstream of greater than 150Mbps and downstream better > than 750Mbps. Then, beginning with 8channels on a lan would be a starting point. When that works we can add channels as see what happens. > Also, there is a very useful looking fully self-contained Ethernet chip > that can deliver 25Mbps at application level. This is the WIZnet W5000. > It can also open up to 4 sockets, so I'm not clear as to whether that > is 25Mbps per socket, or in total. I found [1]. On a 100Mb/s net it must be "total". In a simple test a few years ago I got 50Mb/s between two ordinary pcs. > Very empirically speaking, with 1 channel at 24 bit depth that's a > potential sample rate of 1MHz, Isn't the sample rate something like 44.1, 48, or 96kHz ? Data rate for 1ch * 24bit * 48kHz = 1.152 Mb/s (+overhead). > or putting it another way 20 channels of > 48k! OK, OK, I know I'm leaving out huge swathes of control, collisions > etc. :) So, if we have multiple 100BASE-TX trough a gigabit switch to a pc with a 1000BASE-T, we "shouldn't" have any problems with the network performance with < 100 channels... Or on with a simple crossed cable only 100Base-tx network, it should be possible to transfer 30-40 channels. ... > Being a bit simplistic if you have a master clock (not necessarily > the computer) send just a timecode at 48kHz everything can lock on to > this immediately, and keep updating its copy of the timecode. For a network solution, that would be the job of PTP (ieee1588) it seems. > Something wanting to transmit audio would then send back it's own ID, > the current timecode followed by up to 24bits of A/D stream. > > Packets would be small and latency low, buffer size could probably also > be quite small. > > The computer would pick up all the incoming data streams and sort them > into their appropriate channels and time points. At this level, the > occasional out of sequence packet could probably be put back into it's > right place with only a relatively small additional buffer - well I > hope so! ... So this would be like Giso's "own protocol" alternative b above ? Regards, /Karl [1] http://www.wiznet.co.kr/en/data/WIZnet_e-brouchure_2009.pdf ----------------------------------------------------------------------- Karl Hammar Aspö Data karl@xxxxxxxxxxx Lilla Aspö 148 Networks S-742 94 Östhammar +46 173 140 57 Computers Sweden +46 70 511 97 84 Consulting -----------------------------------------------------------------------
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