The Framework for Live Uplink Streaming (FLUS) is an enabler for live media streaming from a source entity to a sink
entity. The FLUS offers at least MTSI-based mode for media transmission. When used with MTSI-based mode, FLUS
can be establish live media streaming between UEs or between a source entity and a sink entity, within and in-between
operator networks. The UEs can connect to the MTSI using a 3GPP access network. Compared with MTSI, where the
certain types of QoS for speech or video media used, FLUS can provide a flexible range of QoS, e.g., in the maximum
delay, available bandwidth or packet loss rate tolerated. It can be also possible to operate FLUS without MTSI-based
mode. In addition to providing flexible links, advanced functionalities of FLUS, such as the signalling of immersive
media, can be used to complement existing 3GPP services.
The present document defines a source entity and a sink entity for the FLUS that can be support point-to-point
transmission of audio including speech, video, and text. It defines media handling (e.g., signalling, transport, packetloss
handling, and adaptation), as well as interactivity (e.g., adding or dropping media component during a session when
the geometric range of audio visual media is changed from 180 to 360 degrees or vice versa). The focus is to ensure a
reliable and interoperable service with a predictable media quality while allowing for flexibility in the service offerings.
A FLUS source entity, which may be embedded in a single UE, or in a UE and a separate audio-visual front-end, may
support all or a subset of features specified in this document. When used as a generic framework, no feature or
procedure specified in this document is mandated for the FLUS source entity and the FLUS sink entity. Impact on the
service quality and network capacity is left to the discretion of the implementation and the service utilizing the
framework. For example, configuration of media formats and codecs follows the requirements of the respective service.
When offered as part of a 3GPP services, such as MTSI, the impact on the service quality and network capacity is left to
the discretion of the implementation or service policy.
The specification is written in a forward-compatible way in order to allow additions of media components and functionality in releases after Release 15.