On 7/5/17 10:18 PM, Dale R. Worley wrote:
In a perfect world, the caller would test each media stream for whether
it is "silent", and then all of those that are not silent would be mixed
for presentation to the user. (Humans can usually parse multiple audio
sources.) If an early dialog receives a 18x response but there is no
media stream that can be matched with that callee, it may be valuable
for the calling UA to include an appropriate audio signal in the mix --
a ringing tone for a 180, a forwarding tone for a 181, etc.
In a perfect world the UAC would also try to distinguish in band
ringback from other "more interesting" audio. Mixing multiple ringbacks
is likely to just make a mess, and mixing ringback with voice also isn't
ideal.
My impression is that in practice this doesn't happen enough to expend
much effort on optimizing it.
Thanks,
Paul
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