Video Blocking

SIP Server provides the ability to block video streams from SDP offers during the call negotiation/establishment process, so video will not be played when a call is established.

With this feature enabled:

• If an SDP offer contains both audio and video media types, only the audio stream is available for the call.
• If an SDP offer contains only a video media type and no other media types are available for negotiation, the call is rejected.

The following is an example of the SDP body message containing both audio and video media types (highlighted):

   
      v=0
      o=alice 2890844526 2890844526 IN IP4 host.dalycity.example.com
      s=
      c=IN IP4 host.dalycity.example.com
      t=0 0
      m=audio 49170 RTP/AVP 0 8 97
      a=rtpmap:0 PCMU/8000
      a=rtpmap:8 PCMA/8000
      a=rtpmap:97 iLBC/8000
      m=video 51372 RTP/AVP 31 32
      a=rtpmap:31 H261/90000
      a=rtpmap:32 MPV/90000

When video blocking is enabled, SIP Server blocks (removes) the video media stream, as indicated in the following:

   
      v=0
      o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
      s=
      c=IN IP4 host.atlanta.example.com
      t=0 0
      m=audio 49170 RTP/AVP 0 8 97
      a=rtpmap:0 PCMU/8000
      a=rtpmap:8 PCMA/8000
      a=rtpmap:97 iLBC/8000

Feature Limitation

SDP media stream type filtering is not performed when SIP Server is placed out of the signaling path (OOSP).

Feature Configuration

The sip-filter-media configuration option enables this feature. The option can be set at both Application and DN levels. The option setting at the DN level takes precedence over the Application-level setting.

Application level: sip-filter-media

Default Value: No default value
Valid Values: video
Changes Take Effect: Immediately

When set to video, SIP Server blocks video media streams in calls.

DN level: sip-filter-media

Default Value: No default value
Valid Values: none, video
Changes Take Effect: Immediately

When set to video, SIP Server blocks video media streams in calls coming to or originating from this DN. When set to none, SIP Server does not block video media streams, even if the sip-filter-media option is enabled at the Application level. The option can be configured on DNs of type Extension, Trunk, Trunk Group, or Voice over IP Service.