Packetization-mode=1 indicates that UCConfig Mode 1 is the maximum supported SVC scalability mode. 90000 indicates the clock rate and is used by all the listed Lync video codecs. M=video 52884 RTP/AVP 122 121 123 indicates the order of preference to use video codecs is 122 121 123Ī=rtpmap:122 X-H264UC indicates that 122 is the PT for Microsofts specific version of H.264 SVC But as it's in the dynamic range, be aware that in another trace, any number in the 96-127 range could then relate to X-H264UC. So for example, in the below trace, 122 relates to X-H264UC which is Microsoft's specific version of H.264/SVC. The dynamic range is 96-127, so as the name implies, the PT number allocated to a specific codec in this range could change between different conference sessions. These Payload Type numbers fit into categories as being either reserved assigned to a specific codec unassigned or dynamic. They identify the actual codec against its name. The number assigned to each codec is referred to as its PT or Payload Type. In the RTP/AVP (RTP Audio Video Profile) statement, the format is:Ī=rtpmap: payload type codec name / clock rate Real-Time Protocol Audio Video Profile - RTP/AVP: It also states that a value of 0 MUST NOT be used therefore the only valid UCConfing Mode is 1 SVC Temporal Scalability with Hierarchical P.įurthermore, from Appendix D, we know that in a communications trace of the latest Skype for Business 2015 (.1000), the SDP SIP INVITE statement captured in the SfB clients Lync-UccApi.UccApilog log file lists all the supported audio and video codecs. This documents states that the values of 2 or higher MUST NOT be used. So let's take a closer look at the latest codecs in Lync 2013 and Skype for Business 2015.ĭetermining what codecs are used by Skype for Business:įrom Appendix A, we know that there are 5 UCConfig Modes (levels) and that Microsoft will be using the H.264 SVC technology developed by Polycom, but in its implementation of H.264 SVC for Skype for Business 2015 and Lync 2013, Microsoft appear to only use Mode 1.Īccording to the Microsoft document 2.2.12.2 Video Source Request (VSR) that relates to their H.264 SVC, there is a parameter that sets the maximum UCConfig Mode the receiver can support. We now know that for native integration, a third-party endpoint must share common audio and video codecs with Skype for Business.
Skype for Business Video and Audio Codecs: It is recommended that you look all the papers listed below for a background into Skype for Business and a detailed explanation about the Codecs, Protocols, Procedures and some of the available solutions. Whilst Lync 2013 has now been renamed Skype for Business 2015, it is generally backwards compatible with Lync Server 2013. The paper is specifically based on Skype for Business 2015. Within these papers the terms, Lync, Skype, Skype for Business and SfB, unless stated otherwise, all refer to Skype for Business Server 2015. We will look at each of the video and audio codecs available to Skype for Business 2015 when A/V Conferencing and Application Sharing this will then highlight the differences and challenges that need to be resolved when integrating with H.323 or SIP based systems.
Hence, it will focus on codecs used in A/V Conferencing and Application Sharing.
#Skype for business videos series
This paper provides a backgrounding into the Video and Audio Codecs used by Skype® for Business 2015 and is Appendix B of a series that specifically looks at Microsoft® Skype for Business 2015 (Lync® 2013) and the challenges and solutions for integrating Skype for Business 2015 with H.323 or SIP standards compliant videoconferencing systems.
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