IABM Blog - Professional Networked Media - Where are we now? 02 March 2016Professional Networked Media; where are we now? Blog by IABM Technology Consultant Paul Treleaven
There have been predictions that our industry will switch from SDI interfaces to IP network interfaces for live production for a few years now. However, like many game-changing new technologies, the path between papers at conferences and adoption in production facilities is not a straight one; high expectations soon diminish as technical problems are encountered and enthusiasm only returns when workable solutions are implemented.
Of course, some media applications have used IP for many years. One is the transport of media streams by telcos using RTP encapsulation of SDI, based on SMPTE ST 2022-6 or proprietary methods; the user just sees an SDI BNC at each end and the telco functions as a giant IP router, sometimes country-wide. Another obvious one is file-based post-production over IP networks.
However, despite the clear advantages of live production over IP, it has lagged behind awaiting some key ingredients. Fortunately these are now available, notably: media synchronization standards; standards defining individual essence streams; interoperability plugfests; examples of successful implementations; organizations formed to promote IP production technology.
Media Synchronization using AES67 for audio streams and SMPTE ST 2059 for video streams. These two organizations are currently holding joint meetings to define parameter ranges for the Precision Time Protocol that will work for both audio and video applications.
Standards defining individual essence streams, rather than packetization of an audio-embedded SDI stream, lead to much simpler production operations.
For audio-only functions, we have the well-supported AES67 High-performance streaming audio-over-IP interoperability standard; prior to AES67 there had been a chaotic 10 years of multiple non-interoperable proprietary solutions.
For video + audio operations, the Video Services Forum (VSF) has published a Technical Recommendation Transport of Uncompressed Elementary Stream Media over IP (TR-03, downloadable) that collects the following specifications together to form an ecosystem.
TR-03, which is currently being standardized by SMPTE, comprises: AES67 for audio streams and synchronization; SMPTE 2059 for media synchronization (primarily video); IETF RFC 4175 for video streams (supports SD, HD, UHD and beyond); IETF RFC xxxx for ancillary data (draft available as draft-ietf-payload-rtp-ancillary ). It also specifies a number of other long-standing IETF RFC's for the RTP environment.
Interoperability Plugfests to verify that the standards are unambiguous and implementable. Holding plugfests sends a clear message that implementations are out there!
Two AES67 plugfests have been held, in Munich October 2014 and Washington DC November 2015; both were successful and identified small areas where AES67 could benefit from clarification.
One SMPTE 2059 plugfest was held in Houston November 2015 and four more are being planned for 2016, one may be jointly with IEEE1588 (the underlying network sync technology).
The Advanced Media Workflow Association held a workshop in London January 2016 (the AMWA Networked Media Incubator) where a range of industry suppliers tested and demonstrated their ability to interoperate using live IP. The tests included interchange of essence streams compliant with VSF TR-03, RTP header extensions for identity and timing, AMWA's Discovery and Registration API. A further workshop is scheduled for March 2016. AMWA also has a Networked Media Open Specifications page.
Most recently, the VSF demonstrated interoperability between various combinations of TR-03 and TR-04 technologies during their Vidtrans event in New Orleans at the end of February. A large number of suppliers participated in the demonstrations.
Successful implementations demonstrate when technology has come out of the lab and into operational facilities. Two good examples are the fully-IP production of the February 2016 Superbowl and the Belgian broadcaster VRT's IP-based live TV studio.
The superbowl event went off without a hitch and demonstrated the economy in cabling with IP, the use of an IP media router and seamless integration with other IP equipment such as the stadium scoreboard. The IABM has just completed a joint event with VRT and EBU on 29 February and 1 March 2016 to demonstrate the fully-functional VRT studio and participate in discussions and a multi-camera debate.
Organizations formed to promote IP production technology. Some organizations like AMWA, VSF, EBU, have been advocating IP technology for some while however two organizations have launched over the last few months specifically to promote approaches to IP production technology.
The Alliance for IP Media Solutions (AIMS) supports the use of open IP media standards VSF TR-04 which specifies the combination of SMPTE ST 2022-6 with AES67 as an interim solution and VSF TR-03 for the long-term solution.
The Adaptive Sample Picture Encapsulation (ASPEN) community. This community supports open IP standards, but differs from the VSF approach by the use of MPEG-2 Transport Stream to encapsulate the essence.
So, is everything in place? That would be an unreasonable expectation! As we have found over the years with technologies like MXF, there are always bolt-ons needed to solve interoperability problems that become apparent. At the moment, for instance, there are proprietary solutions for implementing frame-accurate media switching using IP routers and software-defined networking (SDN). A SMPTE Study Group is compiling a report on this topic, Flow Management in Professional Media Networks , and will shortly issue a technology provider questionnaire to assess the support availa
