| RFC 0000 | CLUE Framework | June 2020 |
| Duckworth, et al. | Standards Track | [Page] |
This document defines a framework for a protocol to enable devices in a telepresence conference to interoperate. The protocol enables communication of information about multiple media streams so a sending system and receiving system can make reasonable decisions about transmitting, selecting, and rendering the media streams. This protocol is used in addition to SIP signaling and Session Description Protocol (SDP) negotiation for setting up a telepresence session.¶
This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc0000.¶
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The Synchronization Identity MCC attribute indicates how the individual Captures in multiple MCC Captures are synchronized. To indicate that the Capture Encodings associated with MCCs contain Captures from the same source at the same time, a Provider should set the same Synchronization Identity on each of the concerned MCCs. It is the Provider that determines what the source for the Captures is, so a Provider can choose how to group together Single Media Captures into a combined "source" for the purpose of switching them together to keep them synchronized according to the SynchronizationID attribute. For example, when the Provider is in an MCU, it may determine that each separate CLUE Endpoint is a remote source of media. The Synchronization Identity may be used across media types, i.e., to synchronize audio- and video-related MCCs.¶
Without this attribute it is assumed that multiple MCCs may provide content from different sources at any particular point in time.¶
For example:¶
+=======================+=================================+
| Capture Scene #1 | |
+-----------------------|---------------------------------+
| VC1 | Description=Left |
| VC2 | Description=Center |
| VC3 | Description=Right |
| AC1 | Description=Room |
| CSV(VC1,VC2,VC3) | |
| CSV(AC1) | |
+=======================+=================================+
| Capture Scene #2 | |
+-----------------------|---------------------------------+
| VC4 | Description=Left |
| VC5 | Description=Center |
| VC6 | Description=Right |
| AC2 | Description=Room |
| CSV(VC4,VC5,VC6) | |
| CSV(AC2) | |
+=======================+=================================+
| Capture Scene #3 | |
+-----------------------|---------------------------------+
| VC7 | |
| AC3 | |
+=======================+=================================+
| Capture Scene #4 | |
+-----------------------|---------------------------------+
| VC8 | |
| AC4 | |
+=======================+=================================+
| Capture Scene #5 | |
+-----------------------|---------------------------------+
| MCC1(VC1,VC4,VC7) | SynchronizationID=1 |
| | MaxCaptures=1 |
| MCC2(VC2,VC5,VC8) | SynchronizationID=1 |
| | MaxCaptures=1 |
| MCC3(VC3,VC6) | MaxCaptures=1 |
| MCC4(AC1,AC2,AC3,AC4) | SynchronizationID=1 |
| | MaxCaptures=1 |
| CSV(MCC1,MCC2,MCC3) | |
| CSV(MCC4) | |
+=======================+=================================+
| Capture Scene #1 | |
|---|---|
| VC1 | Description=Left |
| VC2 | Description=Center |
| VC3 | Description=Right |
| AC1 | Description=Room |
| CSV(VC1,VC2,VC3) | |
| CSV(AC1) | |
| Capture Scene #2 | |
| VC4 | Description=Left |
| VC5 | Description=Center |
| VC6 | Description=Right |
| AC2 | Description=Room |
| CSV(VC4,VC5,VC6) | |
| CSV(AC2) | |
| Capture Scene #3 | |
| VC7 | |
| AC3 | |
| Capture Scene #4 | |
| VC8 | |
| AC4 | |
| Capture Scene #5 | |
| MCC1(VC1,VC4,VC7) | SynchronizationID=1 MaxCaptures=1 |
| MCC2(VC2,VC5,VC8) | |
| MCC3(VC3,VC6) | MaxCaptures=1 |
| MCC4(AC1,AC2,AC3,AC4) | SynchronizationID=1 MaxCaptures=1 |
| CSV(MCC1,MCC2,MCC3) | |
| CSV(MCC4) |