[AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix-08.txt - please review

Gunnar Hellström <gunnar.hellstrom@ghaccess.se> Fri, 09 October 2020 19:37 UTC

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Subject: [AVTCORE] draft-ietf-avtcore-multi-party-rtt-mix-08.txt - please review
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I would like to get review comments on 

There are three small changes pending:

1. The reference to the WebRTC transport of T.140 real-time text is 
about to be changed from 
draft-ietf-mmusic-t140-usage-data-channel-14.txt to RFC 8865, but even 
if RFC 8865 is ready, it is awaiting common publication of a cluster of 
WebRTC related drafts.

2. A bit more detail in section 2.1.23 about the recovery situations in 
case of packet loss.

3. Correction of a minor error  in 2.1.23, where "A1" in the text under 
packet 6 should be "A3".

Any further comments would be appreciated so that the draft can be 


Den 2020-08-12 kl. 20:52, skrev Gunnar Hellström:
> A new version of the "RTP-mixer formatting of multi-party Real-time 
> text" is available.
> This version moves forward with only two methods for multi-party 
> mixing of RTP transported real-time text.
> The major one is RFC 4103 with transmission interval of 100 ms when 
> there is text from more than one source to transmit, and source 
> indicated in the CSRC list.
> The second one is the fallback for the situation that the endpoint 
> does not have multi-party capability.
> Regards
> Gunnar
> Den 2020-08-12 kl. 20:44, skrev internet-drafts@ietf.org:
>> A New Internet-Draft is available from the on-line Internet-Drafts 
>> directories.
>> This draft is a work item of the Audio/Video Transport Core 
>> Maintenance WG of the IETF.
>>          Title           : RTP-mixer formatting of multi-party 
>> Real-time text
>>          Author          : Gunnar Hellstrom
>>     Filename        : draft-ietf-avtcore-multi-party-rtt-mix-08.txt
>>     Pages           : 36
>>     Date            : 2020-08-12
>> Abstract:
>>     Real-time text mixers for multi-party sessions need to identify the
>>     source of each transmitted group of text so that the text can be
>>     presented by endpoints in suitable grouping with other text from the
>>     same source.
>>     Regional regulatory requirements specify provision of real-time text
>>     in multi-party calls.  RFC 4103 mixer implementations can use
>>     traditional RTP functions for source identification, but the mixer
>>     source switching performance is limited when using the default
>>     transmission characteristics with redundancy.
>>     Enhancements for RFC 4103 real-time text mixing is provided in this
>>     document, suitable for a centralized conference model that enables
>>     source identification and source switching.  The intended use is for
>>     real-time text mixers and multi-party-aware participant endpoints.
>>     The specified mechanism build on the standard use of the CSRC 
>> list in
>>     the RTP packet for source identification.  The method makes use of
>>     the same "text/red" format as for two-party sessions.
>>     A capability exchange is specified so that it can be verified that a
>>     participant can handle the multi-party coded real-time text stream.
>>     The capability is indicated by use of a media attribute 
>> "rtt-mix-rtp-
>>     mixer".
>>     The document updates RFC 4103[RFC4103]
>>     A specifications of how a mixer can format text for the case when 
>> the
>>     endpoint is not multi-party aware is also provided.
>> The IETF datatracker status page for this draft is:
>> https://datatracker.ietf.org/doc/draft-ietf-avtcore-multi-party-rtt-mix/
>> There are also htmlized versions available at:
>> https://tools.ietf.org/html/draft-ietf-avtcore-multi-party-rtt-mix-08
>> https://datatracker.ietf.org/doc/html/draft-ietf-avtcore-multi-party-rtt-mix-08 
>> A diff from the previous version is available at:
>> https://www.ietf.org/rfcdiff?url2=draft-ietf-avtcore-multi-party-rtt-mix-08 
>> Please note that it may take a couple of minutes from the time of 
>> submission
>> until the htmlized version and diff are available at tools.ietf.org.
>> Internet-Drafts are also available by anonymous FTP at:
>> ftp://ftp.ietf.org/internet-drafts/
>> _______________________________________________
>> Audio/Video Transport Core Maintenance
>> avt@ietf.org
>> https://www.ietf.org/mailman/listinfo/avt
Gunnar Hellström