Re: [MMUSIC] Telephone-event and multiple clock rates

[Magnus Westerlund <[e-mail]>]

Hi,

My understanding for the reasoning behind this definition in the RFC is
due to that the events is supposed to be connected to the same time-line
as the audio. Thus it ended up using the same SSRC. To avoid timestamp
rate switching which we know has issues
(https://datatracker.ietf.org/doc/draft-ietf-avtext-multiple-clock-rates/)
it was mandated to provide one PT for each rate negotiated for the audio
payload types.

On 2014-01-24 08:19, Stach, Thomas wrote:
> 
> It still remains interesting what his means if two codecs with different
> clock rates were negotiated and codec-switching-on-the-fly happens.
> 

So there is a difference in negotiating possible to use, another to
actively switch between them within a RTP session for a particular media
source. If you actually switch then you have to take the considerations
in draft-ietf-avtext-multiple-clock-rates into account.

If you are not switching, then these are only ensuring that you can use
the events for what ever audio payload format you select to use out of
the set offered and accepted.

Cheers

Magnus Westerlund

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