Media handling of Multimedia Telephony Service over IMS, MTSI, are based on 3GPP SA4 TS 26.114. MTSI media handling is referred to by GSMA in GSMA PRD IR.92 [21] also known as VoLTE and GSMA PRD IR.94 [22] also known as video over LTE. MTSI clients can connect to conferencing IMS communication services. 3GPP conducted a study as part of a work item on Multi-stream Multiparty Conferencing Media-Handling for MTSI. The work objective is to specify an increment to MTSI client media-handling specification TS 26.114 to enable a mass-market multiparty communication service with excellent multiparty user experience and media quality. Such Operator communication service evolution would match proprietary communication services in quality with excellent efficiency and device reach. The present document captures the study inputs, discussions and findings of the Multi-stream Multiparty Conference Media Handling (MMCMH) work item. It describes a set of use cases with corresponding problem descriptions and potential solutions. The conclusion gives recommendations as to what needs to be normatively specified to achieve the MMCMH work item objectives.

The Technical Report provides a study on the media handling aspects of Multi-stream Multiparty Conferencing for MTSI. The study focuses on enabling

• support to receive multi-stream audio/video at the terminals in a multiparty conferencing,
• support for at least two video contents, e.g. one main and one presentation,
• talker ID provisioning,
• compatibility with MTSI TS 26.114 and GSMA IR.94 (Video over LTE) [22] and GSMA IR.92 (VoLTE) [21], and
• applicability to both mobile and fixed access terminals

High-level use cases along with current limitations and recommendations are documented in the present document.