{
  "draft": "draft-ietf-avtcore-multi-party-rtt-mix-20",
  "doc_id": "RFC9071",
  "title": "RTP-Mixer Formatting of Multiparty Real-Time Text",
  "authors": [
    "G. Hellstr\u00f6m"
  ],
  "format": [
    "XML",
    "TEXT",
    "HTML",
    "PDF"
  ],
  "page_count": "35",
  "pub_status": "PROPOSED STANDARD",
  "status": "PROPOSED STANDARD",
  "source": "Audio/Video Transport Core Maintenance",
  "abstract": "This document provides enhancements of real-time text (as specified in RFC 4103) suitable for mixing in a centralized conference model, enabling source identification and rapidly interleaved transmission of text from different sources. The intended use is for real-time text mixers and participant endpoints capable of providing an efficient presentation or other treatment of a multiparty real-time text session. The specified mechanism builds on the standard use of the Contributing Source (CSRC) list in the Real-time Transport Protocol (RTP) packet for source identification. The method makes use of the same \"text/t140\" and \"text/red\" formats as for two-party sessions.\n\n Solutions using multiple RTP streams in the same RTP session are briefly mentioned, as they could have some benefits over the RTP-mixer model. The RTP-mixer model was selected to be used for the fully specified solution in this document because it can be applied to a wide range of existing RTP implementations.\n\n A capability exchange is specified so that it can be verified that a mixer and a participant can handle the multiparty-coded real-time text stream using the RTP-mixer method. The capability is indicated by the use of a Session Description Protocol (SDP) (RFC 8866) media attribute, \"rtt-mixer\".\n\n This document updates RFC 4103 (\"RTP Payload for Text Conversation\").\n\n A specification for how a mixer can format text for the case when the endpoint is not multiparty aware is also provided.",
  "pub_date": "July 2021",
  "keywords": [
    "conference",
    "bridge",
    "SIP"
  ],
  "obsoletes": [],
  "obsoleted_by": [],
  "updates": [
    "RFC4103"
  ],
  "updated_by": [],
  "see_also": [],
  "doi": "10.17487/RFC9071",
  "errata_url": null
}