Re: [MMUSIC] a=rtcp-mux-exclusive vs a=rtcp:0 compression

Den 2016-04-05 kl. 18:36, skrev Roman Shpount:
> I have modified the proposed SDP slightly. I have removed IN IP4 0.0.0.0
> from a=rtcp attribute. I cannot find a place that states that a=rtcp is
> required when rtcp-mux is used, so I removed a=rtcp from the
> rtcp-mux-exclusive examples.

RFC 5761 has the following sentence in Section 5.1.1:

    Instead,
    it should send and receive RTCP on a port allocated according to the
    usual port-selection rules (either the port pair, or a signalled port
    if the "a=rtcp:" attribute [10] is also included).

So, I would agree that a=rtcp is not mandatory based on RFC 5761, it do 
results in that the fall back for RTCP is m= port+1. But, as this is 
intended for the case of not having any fallback.

However JSEP do contain text that appears to require that a=rtcp are 
included. This, may be changed to support the mux-exclusive usage. 
However, I haven't checked if this requirement is due to trickle ICE.

/Magnus

  Also, since we are shaving bits, I did a
> version with SDP attribute named rtcp-mux-only, which is 5 bytes
> shorter. So, my results are:

>
>                | port 0 | -exclusive | -only|
> ---------------------------------------------
> Uncompressed  |   1438 |       1462 |  1452 |
> Compressed    |    716 |        725 |   720 |
>
> Regards,
>
> _____________
> Roman Shpount
>
> On Tue, Apr 5, 2016 at 10:14 AM, Justin Uberti <juberti@google.com
> <mailto:juberti@google.com>> wrote:
>
>     Minor point for the beauty contest...
>
>     Compressing the attached SDP files (adapted from the examples in
>     https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-14#section-7.1)
>     with gzip (default settings) gives the following output:
>
>                    | port 0 | -exclusive |
>     -------------------------------------
>     Uncompressed  |   1467 |       1487 |
>     Compressed    |    723 |        739 |
>
>
>
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-- 

Magnus Westerlund

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