Controlling media capability

Calls consist of three types of media - audio, video, and presentation - each in their own stream. Pexip Infinity allows you to control which types of media can be used for certain calls. This feature allows better resource management and smaller Session Description Protocols (SDPs) when calling out to known audio-only devices.

Limiting media capability

You can restrict the media capability either on a per-call basis (the call capability) or a per-conference basis (the conference capability), as follows:

Adding a participant to a conference

When dialing out to a participant from within a conference, either manually or automatically, you can choose whether the call will be audio-only, main video only, or main video plus presentation. In such cases, the called participant will not be able to escalate the call (for example, from an audio-only call to video).

Conference-wide limitations

You can apply limits to individual Virtual Meeting Rooms (including scheduled conferences) or Virtual Auditoriums, restricting them to be audio-only, main video only, or main video plus presentation. In such cases, participants calling in to the conference with a higher media capability will have their media limited. For example, when a participant dials in over video to an audio-only VMR, their call will be placed as audio-only and they will not subsequently be able to escalate the call.

Using the audio-only setting where appropriate also has the advantage of increasing the overall capacity of your distributed deployment. Each Conferencing Node will reserve an extra connection for each Virtual Meeting Rooms and Virtual Auditoriums it is hosting, to be used for a backplane should that service become distributed (i.e. hosted on more than one Conferencing Node). By default this connection will be equivalent in capacity to an HD call, but if the service has been configured as audio-only it will instead be equivalent to that of an audio-only call. For further information on capacity and how calls consume resources, see Hardware resource allocation rules.

Virtual Receptions

You can limit the conference capability of a Virtual Reception. Any restrictions will be applied to calls while they are accessing the Virtual Reception service (apart from Connect apps, which do not access a Virtual Reception in the same way as other endpoints). When the call is placed to the destination Virtual Meeting Room or Virtual Auditorium, the capability of that service will be available instead, but may or may not be used by the endpoint, as follows:

  • Connect apps making a video call via an audio-only Virtual Reception will always join a video-capable VMR with video
  • Connect apps making an audio-only call via an audio-only Virtual Reception will join a video-capable VMR with audio-only initially, but with the option of enabling video.
  • Skype for Business / Lync clients making a call via an audio-only Virtual Reception will always join a video-capable VMR as audio-only initially, but with the option of enabling video.
  • Standards-based endpoints making a video call via an audio-only Virtual Reception will always join a video-capable VMR as audio-only initially. Depending on the endpoint, there may be the option to then enable video.

For example, if you limit your Virtual Reception to audio-only, when Alice calls it from her standards-based endpoint she will not receive any video and will only hear the audio prompts. However, when her call is then placed to the destination VMR which has a capability of main video, she will initially join it as audio-only but will be able to elect to send and receive video as well.

Infinity Gateway calls

For calls made using the Distributed Gateway, you can configure the relevant Call Routing Rule to limit the media by selecting an appropriate Call capability setting:

  • You can limit the media capability of the outbound call to audio-only, main video only, or main video plus presentation. For example, if the media capability is set to audio-only and Alice makes a video call to Bob, Bob will not be able to answer with video.

  • You can match the capability of the outbound call to that of the inbound call by using the Same as incoming call option. This means that if, for example, Alice makes an audio-only call to Bob, Bob will not be able to answer with video.

    Note that, when using Same as incoming call:

    • an audio-only call cannot later be escalated to video
    • auto-escalation of Skype for Business / Lync calls (if enabled) will not work
    • for an H.323 audio-only call to a Skype for Business / Lync client, the SfB/Lync client will be offered both audio and video.

Automatically escalating Skype for Business / Lync audio calls

You can control how Pexip Infinity handles incoming audio-only calls from Skype for Business / Lync* clients.

By default, Pexip Infinity treats the call as audio-only and does not send video back to the SfB/Lync participant.

This behavior can be changed on a platform-wide basis by selecting the Enable Skype for Business / Lync auto-escalation setting from Platform > Global settings > Connectivity.

When SfB/Lync auto-escalation is enabled, Pexip Infinity automatically escalates a SfB/Lync audio-only call so that it receives video from a conference (the SfB/Lync participant still only sends audio).

The following table shows the differences in conference experience based on the auto-escalation setting when a SfB/Lync client makes an audio call to a Pexip conference:

  SfB/Lync auto-escalation configuration
  Disabled (default) Enabled
The SfB/Lync participant... sees the conference avatar image ( by default) receives a video stream from the conference
Other conference participants see the SfB/Lync participant as... an audio-only participant indicator on the left side of the video window ( by default) a "no incoming video" indicator when the participant is shown as the main speaker or as a thumbnail ( by default)

In all cases, the SfB/Lync participant can still subsequently escalate to send (and receive) video.

* Note that where this documentation refers to "SfB/Lync", it represents both Microsoft Skype for Business and Lync unless stated otherwise.