26.1143GPPIP Multimedia Subsystem (IMS)Media handling and interactionMultimedia telephonyRelease 18TS
S.2.1 Conversational video
An MSMTSI client in the terminal shall be capable of receiving and locally composing at least one main video and one or more video thumbnails. A "thumbnail" video is in this context defined as a receive-only video "m="-line that is not the first video "m="-line in the SDP, and that is also not identified with any "a=content:main" or "a=content:slides".
An MSMTSI client in terminal shall support receiving at least one thumbnail and may also support receiving any number of additional thumbnails, subject to MSMTSI client capability. An MSMTSI MRF shall support sending at least two thumbnails and may support sending any number of additional thumbnails, subject to MSMTSI MRF capability.
An MSMTSI client in terminal shall support sending at least one thumbnail-sized simulcast format of the main video, and may support sending also other simulcast formats. An MSMTSI MRF shall support receiving at least one thumbnail-sized simulcast format of the main video, and may support receiving also other simulcast formats.
S.2.2 Non-conversational (screenshare) video
An MSMTSI client may support sending and receiving screenshare video. The first picture of the screen sharing video an MSMTSI client sends after being granted the screenshare BFCP floor (see clause S.5.6) shall be random accessible, i.e., as if a FIR would have been received.