This path also ran flawlessly for a number of years. There is
definitely an imperfection now that wasn't present before, and it's
still eluding me.
The point is they CAN have both lossless audio and error correction if
they RTFM.
On 6/26/2020 10:02 AM, dave wrote:
I did this with couple cisco switches and a ptp800 link with flawless
operation for 4 years and we also had about 100Mbs of
internet access to the studio fed by another site.
for lossless audio the link has to be perfect and have a stamp of 5x9s
of reliability with a measure of fade built into contract.
we did this back in 2014
On 6/25/20 2:15 PM, Adam Moffett wrote:
So some radio station is transporting audio over IP from studio to
tower. A few weeks ago they started getting skips in the audio, and
they're finger pointing at me. At first I couldn't even see a
problem. Eventually I find that every so often there's a 1/10th
second event with packet loss. Seven seconds after the event you
hear a little blip on the radio. You could go a few hours between
events, or only a few minutes.
I said yeah I'll try to track down what's causing that, but if you
have a 7 second delay on this one-way transmission, isn't there
plenty of time to resend 1/10th second of missing audio?
*grumble grumble*, finger point, it worked before, etc
So I've been trying to narrow down where this is happening and swap
interfaces and such. And keep in mind anything I do interrupts the
radio so I have to do it at odd hours. Periodically during the
process I re-ask why does this even happen? This amount of loss
shouldn't hurt you.
*grumble grumble*, finger point, it worked before, etc
So today they let me take a look at their Comrex audio streaming
thing-a-ma-bobbers, and I looked in the manual. Turns out the error
correction features don't work on lossless audio codecs unless your
firmware version is above a certain revision. Theirs isn't above that
revision, and they're using a lossless audio codec. So now I'm like,
yeah I'll keep looking for that little blip, but in the meantime you
don't have to hear it if you'll upgrade your firmware and enable FEC.
They've had a number of people looking at this, including their
engineer. Their equipment has robust enough error correction that
they could run that stuff on satellite or 4G if they wanted to. It's
just not configured right!
You'd have fixed this in half an hour if you'd have RTFM'd you
frickin noobs.
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