Re: [AVT] retransmission payload format

[Magnus Westerlund <magnus.westerlund@era.ericsson.se>]

Hi David,

You are of course correct that most of the statistics is still useful. 
However the two following has issues in the retransmission stream.
SR:
NTP - TS synchronization.
RR:
interarrival jitter

The NTP - TS timestamping should be correct, except around RTP TS rate 
switches when it might behave strange due to the switches. The 
interarrival jitter as mentioned is practically useless.

Cheers

Magnus

David.Leon@nokia.com wrote:

> Magnus,
>
>
> > I think we are in agreement on which solution is the more 
> > proper one in 
> > this case. Using one RTX payload type for each original PT. 
> > The original 
> > TS goes in the retransmitted packets RTP header exactly as 
> > is. All RTCP 
> > statistics for the retransmission stream will be screwed up and is 
> > simply declared as incorrect.
> With the proposed approach, the RTCP jitter for the retransmission stream is not correct in the sense that it does not reflect the actual network jitter. However, I don't see why the other RTCP statistics would be incorrect.
>
> David.
--

Magnus Westerlund 
Multimedia Technologies, Ericsson Research ERA/TVA/A
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S-164 80 Stockholm, Sweden | mailto: magnus.westerlund@era.ericsson.se



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