SAN JOSE, CA. — Technologies that standardize media transport across the public internet and control of IP media production, as well as the new SMPTE 2110 media transport standard, were the subject of several presentations and discussions at the annual May meetings of the Video Services Forum in San Jose, Calif. The meetings, which also included live technology demonstrations, were hosted by Cisco Systems and attended by VSF members and guests from across the U.S. and around the world.
RIST [Reliable Internet Stream Transport], achieved a milestone at the meeting. Six vendors, including Cobalt, DVEO, Nevion, QVidium, Videoflow and Zixi, provided a live, multivendor live interoperability demonstration of contribution-quality video signals being transported over the open internet. RIST uses a technique called ARQ [Automatic Repeat request], where the receiver is able to detect missing packets in an incoming signal stream and request them to be automatically retransmitted by the sender. This process allows single-packet or burst errors that are not uncommon in internet transport to be corrected, allowing a clean video and audio signal to be delivered.
While a number of companies provide proprietary solutions that accomplish the same thing, RIST is the first completely open, standards-based protocol that has been independently implemented by multiple vendors. The VSF is currently putting the finishing touches on the first release of RIST, which should be publicly available in the coming months. Future enhancements are planned that will support interoperable encryption, multipoint/multipath distribution, VPN tunneling and other advanced features.
[Read: SMPTE ST 2110-21: Taming the Torrents]
The initial version of the RIST specification is nearing completion (as evidenced by the successful interop demonstration during the May VSF meetings) and should be released in the coming months. Discussions are also underway for potential future public demonstrations of RIST technology at industry trade shows later in 2018.
NMOS [Networked Media Open Specifications] is rapidly becoming a necessity for IP-based production systems. These are being developed under the auspices of AMWA [Advanced Media Workflow Association], but they have featured heavily at the VSF, including a live interop demo at VidTrans in February. While the signal formats for uncompressed video and audio have been published as SMPTE ST 2110, these mechanisms that are used for higher level network functions are just as important for a smooth operation. Three of the NMOS specs were discussed in detail during the VSF meeting:
- IS-04 for Registration and Discovery was released first, and covers the procedures that devices use to announce their presence on a network and to figure out which other devices are also present on the network. This is an important first step in any process for network management — without knowing the identities of the devices on the network, it is impossible to manage or communicate with them.
- IS-05 for Connection Management was released last fall, and covers the procedures that endpoints (cameras, servers, displays, etc.) use to set up connections to other endpoints to send or receive specific signals. Since each media type (video audio, metadata) is sent as a separate stream in SMPTE ST 2110, making a connection can involve managing multiple IP packet streams and addresses.
- IS-06 for Network Control is the newest of the bunch, and is set to be released in the near future. It covers the messages that networking equipment such as Ethernet switches and IP routers need in order to route signals through the IP communications fabric. This is not trivial: connections frequently need to be managed to ensure that the underlying data circuits (often 1 Gbps or 10 Gbps Ethernet links) are not overloaded.
NMOS is significantly different from most of the previous control and monitoring mechanisms used in video production facilities in that it is not a wire-based message protocol, like the many common ones based on RS-422. Since every IP media endpoint (by definition) has an IP network interface, it makes sense to use more advanced, web- and network-friendly protocols and interfaces, including HTTP and RESTful APIs. Accordingly, NMOS does away with defining its own signaling protocol, and instead uses widely-accepted industry standards. This also makes NMOS much easier to integrate with systems that extend beyond a single facility, including remote production venues and cloud-based content processing applications.
Several other technical topics were covered during the VSF meetings. The SVIP [Studio Video over IP] team hosted a panel discussion about a forthcoming VSF specification (TR-05) that will define a set of commonly used IP video formats that are intended to serve as precisely specified interoperability profiles. The JPEG 2000 Ultra Low Latency project is also wrapping up, which adds a new set of profiles to TR-01 that allow a complete JPEG 2000 encode/decode cycle to take place in 6 to 8 milliseconds, instead of the current specification’s 100 milliseconds or more. Attendees at the VSF meeting were also treated to a behind-the-scenes tour of Cisco’s corporate television facility, which is responsible for producing hundreds of events for internal and external audiences.
