[mythtv-users] HDHR prob with new wallwarts

Jan Ceuleers jan.ceuleers at gmail.com
Sun Dec 8 07:46:20 UTC 2019

On 08/12/2019 07:40, Stephen Worthington wrote:
> As for CS3 versus CS5, there are two different ways an HDHR gets used.
> One is where it is being recorded, and the other is where it is being
> watched directly by a human.  For a recording, it would actually be
> better to use a TCP connection with error correction and
> retransmission, so you could under most circumstances ensure that
> there were zero lost or damaged packets.  It does not matter to a
> recording device if the packets arrive a little late and with variable
> timing.  So if a TCP connection is used, in theory it would not be
> necessary to use a DSCP priority tag at all.  Where a human is
> watching though, the error correction involved in a TCP connection is
> usually unacceptable as it causes "buffering" moments where the
> playback stops.  So for a human, a high priority for the traffic is
> necessary to allow the packets to not be dropped and to travel with
> low jitter.  So that might well justify using CS5 instead of the CS3
> recommended by RFC4594.  For recording using UDP packets, CS3 should
> be all that is necessary.

Stephen, I am wondering about circumstances under which packet drops
would occur in a home network at all. Furthermore I am wondering whether
you'd have an intelligent device in a home network making decisions
about which packets to drop, or whether any such packet dropping would
be done by consumer-class boxes that lack the smarts to look at packet

The topic you describe is relevant in an enterprise network, but in a
home network?

The only in-home scenario I can think of is WiFi APs, given that WMM has
been a mandatory feature of the standards for some time now. Still, it
seems that the mapping of DSCP values to WMM access categories is
inconsistent across WiFi vendor implementations, so not very useful in

Cheers, Jan

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