Maintenance Manual

By default, participants' ability to contribute content video (technically, as above, to start contributing H.239 or BFCP
video) is determined by the per-conference Content contribution from endpoints setting (Conferences > Add new
conference).
The per-conference default Content contribution from endpoints setting can be overridden by individual endpoints'
configuration. If such an endpoint's Content contribution setting is <use conference default> then the endpoint's
ability to contribute content channel video will be determined initially from the conference setting. If the endpoint
setting is <enabled> or <disabled> then this will override the conference setting and that endpoint will either always
be prevented from using content, or always permitted (assuming the conference of which it is part is configured with
content channel support). As well as being part of each endpoint's configuration, the Content contribution setting
can also be specified when calling out to an endpoint by address.
Irrespective of per-conference or per-endpoint configuration parameters, if a conference is configured to allow
content channel operations then it is possible to explicitly enable or disable individual conference participants' ability
to use content via the web browser interface (assuming a user login with full conference control).
To change the content contribution setting for an active conference participant via the web interface, first navigate
to that participant's Display page (go to Conferences and click the conference you want and then click on the name
of the participant whose settings you want to change). If the conference has content enabled and the endpoint in
question has content capabilities, you should be able to use one of the following controls:
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allow participant to contribute content video
■
do not allow participant to contribute content video
If an endpoint's ability to contribute content video has been explicitly enabled or disabled via this mechanism, that
enablement or disablement will take precedence over any current or future conference or participant configuration,
even if the endpoint later moves to a different conference.
Use of Main Video as Content Channel
In addition to supporting the H.239 and BFCP protocols by which endpoints in a conference can supply the content
channel video, the MCU also allows a participant's main video channel to be used for the content stream. This is
essentially what happens by default for VNC connections in a conference configured to allow content channel video.
As detailed above, it is not possible to force an endpoint that has started to contribute content video to relinquish the
virtual token that it holds. Thus, if you select an endpoint's main video channel to be the content channel source, this
will only take effect if no other endpoint is supplying the content channel video stream (whether by H.239, BFCP, or
through use of its main video stream). However, if you have enabled Automatic content handover on the Settings >
Content page and you select an endpoint's main video channel to be the content source, this will take effect even if
there is currently another content source in the conference.
To control the use of a participant's main video as the conference content channel source, the following controls are
displayed on the per-conference participant list (next to the preview image of the video stream to which they relate):
■
use this participant's main video stream as the content channel (this is set by default for VNC
connections)
■
stop using this participant's main video stream as the content channel (revert to more conventional
content channel behavior such as H.239)
In rare circumstances, if more than one participant's main video channel is configured to provide the content channel
(for example where a participant configured in this way is moved to another conference where there is an existing
participant providing his main video channel as the content channel), then all but the active (normally, first) one will
be marked with the status: Content: unable to use main video as source
You might also see this warning if there is more than one VNC connection in a conference, because, when
establishing a new VNC connection, the MCU will automatically configure its main (in fact, sole) video channel to be
used as the content channel source if possible. To choose between multiple potential main video channels as the
content source for the conference, use the control to stop using this participant's main video channel as the
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