9 Jun
2015
9 Jun
'15
4:14 a.m.
On 06/07/2015 07:15 AM, Len Ovens wrote:
...
Why is this? Linux is based on lowest common
denominator hardware... we
call it the PC. The Linux world has gotten much better preformance out
of this box than it was designed for. But, in the case of audio, the HW
does limit performance at least with AoIP. That limit is the clock. The
PC does not have a HW PTP clock built in and in this case software is
not good enough. The way around this is with a custom NIC that does. For
some reason even though one can buy an ethernet chip that includes a
stable PTP clock for less than $5, any NICs I have found with a PTP
clock are closer to $1k.
An Intel I210 Gigabit Ethernet PCI express Card will set you back about
$70 on Newegg, it does have the hardware support that AVB needs and a
driver in the OpenAVB project. I have a couple and they seem to work
just fine. A 24 output AVB Motu box is $995.
I'm actually trying to get this going with one of these AO24 Motu
"soundcards" (starting with OpenAVB). I have gotten as far as the
OpenAVB stack talking to the Motu card and slaving its clock to it (and
the Motu box recognizing it is now the master clock source and AVB is
active). Audio streaming is next, I'm just not finding the free time to
do this (anyone gotten further along on this??).
First goal would be a simple jack client that can stream samples, end
game would be a jack backend so this can be treated as a soundcard.
We'll see...
-- Fernando