[NUT-devel] Broadcasting nuts [PATCH]

[Michael Niedermayer]

On Wed, Feb 06, 2008 at 12:31:06PM -0500, Rich Felker wrote:
> On Wed, Feb 06, 2008 at 05:44:16PM +0100, Michael Niedermayer wrote:
> > > Mark the buffer with actual receive times, according to the local
> > > clock, and correlate them with the timestamps in the NUT stream,
> > > smoothing out any timing adjustments over a long interval that's still
> > > an order of magnitude away from the length needed for drift to become
> > > a problem. 
> > 
> > Ill try again with an even simpler example to make it harder to miss the
> > problem. Eventually you will have a problem to ignore it and pretent
> > some disconnected solution might work
> > 
> > lets assume 1 frame/sec video, and 100byte/sec channel rate
> > Frame 0   dts   0 99byte received at 0
> > Frame 1   dts   1 99byte received at 0.99
> > Frame 2   dts   2 99byte received at 1.98
> > ...
> > Frame 1000 dts 1000 99bytereceived at 990
> > 
> > vs.
> > 
> > 99byte/sec channel rate
> > Frame 0   dts   0 99byte received at 1
> > Frame 1   dts   1 99byte received at 2
> > Frame 2   dts   2 99byte received at 3
> > ...
> > Frame 1000 dts 1000 99byte received at 1000
> > 
> > The above 2 are with atomic clock based transmitters and receivers. 
> > Now assume the clocks drift how are you going to detect let alone compensate
> > for this? Either of the 2 outputs could have come from the other stream if the
> > clock drifts in the right direction.
> 
> A clock this bad would drift by 1/4 an hour per day. I doubt anyone
> would buy such a clock...

No, but people buy various embeded devices to watch videos and their clocks
are supposed to be cheap. And while i dont think they would be off by
15min/day i doubt you can expect more than 1min/day accuracy from them.

Also my HP notebook is 1min off per week or so.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Freedom in capitalist society always remains about the same as it was in
ancient Greek republics: Freedom for slave owners. -- Vladimir Lenin
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