josh wrote:
I hope this is the right list to post to.
I'd like to delay a shoutcast stream by around 2 minutes. This
shoutcast server is used to broadcast commentary on live games and
the delay is needed so teams can't gain an advantage by hearing the
commentary to learn where/what the other team is doing. I've
checked the shoutcast forums and it seems there's nothing I can do
to the shoutcast daemon to get this delay. Shoutcast listens on
tcp/8001 for an input stream, and tcp/8000 for listeners to connect
to.
With 100 streams each using 48kbps, how practical is it to put them
all through a dummynet pipe with a delay of 120000ms? I figure
that'll require 100 * 48 / 8 * 120 / 1024 = 70MB of buffering in
dummynet. That's heaps! Is that possible? Is that using mbufs?
What would have to be tweaked up?
>
I guess it'd be better if I could just add the 2mins of delay to
the input stream so the delay buffer is smaller and fixed, but I
don't know how the shoutcast protocol would like that or how the
different TCP implementations would like it. Would ACKs be coming
back to the shoutcaster 2 minutes late?
Ideally it'd be best to have all this buffering happen intelligently
in userland, but I can't find anything to do that. Am I barking up
the wrong tree by looking at dummynet?
Yes, you most certainly are. The problem with TCP is that using the standard
window sizes (~32-64k) on the client side and the RTT of two minutes,
the transfer speed will naturally be, literally, couple of hundred
bytes per second. You'll not be able to squeeze 48kbps into this pipe.
Moreover, as the reaction time is slow, there will be various timeout-related
glitches, stopping the transfer periodically and restarting it minutes later.
The network-related delays can offer you no more than several seconds delay.
The best approach is, indeed, a buffering application-level daemon.
--
Lev Walkin
[EMAIL PROTECTED]
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