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USING VIRTUAL CSRCS TO DIFFERENTIATE MEDIA FROM DIFFERENT USERS AND CAPTURE SOURCES

IP.com Disclosure Number: IPCOM000240372D
Publication Date: 2015-Jan-27
Document File: 6 page(s) / 62K

Publishing Venue

The IP.com Prior Art Database

Related People

Robert Hansen: AUTHOR [+5]

Abstract

Presented herein are techniques by which media originators add a Contributing Source (CSRC) Identifier (CSI) to all media they send, segmented into a unique, random value to identify the sender and a value to differentiate between different sources that sender has. This CSI is conveyed via the Session Initiation Protocol (SIP) or a roster list, so that a recipient can identify both the originating participant and the media source type (e.g., the tight-focus camera of a tight/wide focus pair) as soon as they receive the first Real-time Transport Protocol (RTP) packet, even if it has gone through a switching or transcoding mixer.

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USING VIRTUAL CSRCS TO DIFFERENTIATE MEDIA FROM DIFFERENT USERS AND CAPTURE SOURCES

AUTHORS:

Robert Hansen Nathan Buckles Nermeen Ismail Mo Zanaty Espen Berger

CISCO SYSTEMS, INC.

ABSTRACT

    Presented herein are techniques by which media originators add a Contributing Source (CSRC) Identifier (CSI) to all media they send, segmented into a unique, random value to identify the sender and a value to differentiate between different sources that sender has. This CSI is conveyed via the Session Initiation Protocol (SIP) or a roster list, so that a recipient can identify both the originating participant and the media source type (e.g., the tight-focus camera of a tight/wide focus pair) as soon as they receive the first Real-time Transport Protocol (RTP) packet, even if it has gone through a switching or transcoding mixer.

DETAILED DESCRIPTION

    Traditional video conferencing is point-to-point, with a single video and audio stream, and perhaps an additional stream for content. However, currently there are a number of more complex scenarios that either already exist or that are being brought to market, and in these cases the recipient can add value by having additional information about the originating source of the media.

    In the case of a multi-point conference, there is a desire for the recipient of a media stream to be able to differentiate which user produced the stream. This allows the recipient to, for instance, superimpose the user's name on the video stream, or to mark the user in the roster list as the 'active speaker'.

Copyright 2015 Cisco Systems, Inc.

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    In the case of a multistream call, in which participants are able to send video or audio from multiple sources (e.g., a system with multiple cameras) it is beneficial for the recipient to be able to identify the association of these streams with one another. For instance, knowing that video stream A represents a lecturer, while stream B represents his audience in the same room, allows the recipient to associate them with their respective audio streams, and intelligently choose what to display prominently.

    Each media packet sent by the originator of that stream contains a Contributing Source (CSRC) value. Additional semantics and constraints are applied to this 32 bit CSRC value, and it is named the Contributing Source Identifier (CSI). The bits of the CSI are segmented into two portions. See FIG. 1 below.

FIG. 1

    Scene ID: This is a random value determined by the media sender that it should use for all media that it sends as part of a single, logical 'scene'. For instance, if an endpoint has two cameras and one microphone, media sent from all three capture devices should share the same Scene ID.

Copyright 2015 Cisco Systems, Inc.

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    It is up to the implementation to define the scope of a scene. For example, adding presentation video to the above two-camera example, the presentation video may be determined to belong to the same scene as the other main video a...