These days, most engineers understand the benefits of migrating to IP networks for audio and video transport. However, many engineers still ask about NMOS (Networked Media Open Specifications) and Ember+ and how these protocols can be used to manage and monitor codec functions and AES67, ST 2110-30 and ST 2022-7 IP streams.
This article explores some of the many benefits of NMOS and Ember+. It references NMOS standards IS-04, IS-05 and IS-07, which standardise control layer elements to allow devices from different manufacturers to interoperate smoothly.
NMOS versus Ember+
NMOS is a set of open standards developed by the Advanced Media Workflow Association (AMWA), which helps to standardise and simplify the interconnection of devices in IP media networks. Tieline audio codecs support NMOS IS-04 (Discovery and Registration) and IS-05 (Connection Management), supporting interoperability, discovery, connection management, and control in IP-based networks. They also support NMOS IS-07 (Events and Tallys), which facilitates sending messages to notify users about issues like stream failure.
Ember+ complements NMOS well. It is another open-source control protocol originally developed by Lawo for broadcast environments. Ember+ allows a third party application to gain access to device parameters via a parameter tree and adjust them. It provides a standardized way for devices like codecs to be remotely controlled, deliver real-time device status and monitoring, and integrate with broadcast control platforms.
Therefore, you could summarize by saying NMOS provides network discovery, establishes connections, and activates events and tallys. Whereas Ember+ controls device functions at a more granular level. For example, in a codec Ember+ may configure physical and logical GPIOs, input and output settings, and connection settings like algorithms, stream names, IP addresses and ports.
Benefits of NMOS and Ember+
AMWA states:
NMOS is the open-source “special sauce” that enables connection, management, and control of your IP video and audio devices from different manufacturers – in a common eco-system and in an interoperable way.
More specifically, the benefits of NMOS include:
- Simple integration of devices from a variety of vendors
- API-driven control of audio stream routing provided across a network
- Smarter integration with IP consoles, routers, and other devices without requiring custom wiring or coding
- Scalability, allowing simple configuration and addition of devices and streams as your network grows
- Increased reliability with event and alarm management
Ember+ on the other hand can facilitate:
- Changing codec programs/profiles
- Responsive remote control of device settings like audio and encoding settings, bitrates and GPIOs
- Real-time status and monitoring of devices
- Reduced complexity with centralized and unified control interfaces replacing multiple GUIs for control
Multi-vendor compatibility is important as this means you can build a network with equipment tailored to your specific needs and requirements by allowing devices from different manufacturers to work together smoothly. The open-source nature of both NMOS and Ember+ makes it simpler to deliver more integrated and affordable studio infrastructure through a simplified control interface.
IS-04 and IS-05: Discovery, Registration and Control
IS-04 defines a framework for Discovery and Registration that allows components within a networked media system to find each other. NMOS IS-05 provides connection management. This is required because essential components for controlling and managing network devices are not included in the SMPTE standards, e.g. AES67 and ST 2110.
NMOS delivers specifications in the form of APIs. In a network supporting NMOS, each node exposes one or more NMOS APIs in order to find, register and control resources on each node. A Tieline codec with NMOS enabled on source and destination IP streams can:
- Register itself via IS-04
- Be connected via IS-05
IS-05 also facilitates seamless switching to a redundant AoIP stream using ST 2022-7, which defines the method for hitless packet switching over IP. An NMOS server in a codec can integrate with freely available software tools, which can discover, manage and connect IP media devices following IS-04 and IS-05 standards. Some of the options include:
- Discovery of nodes, devices and streams
- The ability to view and configure stream parameters – including displaying and copying SDP
- Starting and stopping streams.
IS-07: Events and Tallys
The IS-07 NMOS specification provides a mechanism for facilitating signal exchanges (transmit and receive) for state changes, GPIOs, tally and other triggered events. It is ideal for configuring IP-based logic GPIOs as an alternative to physical GPIOs. It also facilitates provision of real-time status messages to monitor equipment.
Ember+ for Codec Users
An Ember+ server in a codec connects over TCP to expose a device’s internal parameters in a hierarchical Ember+ parameter tree. An Ember+ client uses a control application to connect to the codec and view and adjust settings.
It is very simple to set up. All you need to do is enable Ember+ in the codec and know the codec IP address and Ember+ port. When enabled, the client application accesses the parameter tree and you can then view settings and send commands to modify parameters, while also monitoring operational behaviour in real-time.
Advantages of Unified Operational Interfaces
When devices like audio codecs support both NMOS and Ember+ they support the wider objective of unifying control of devices from multiple manufacturers using a single interface. One well-known broadcast industry interface example is Lawo VSM.
Tieline and other broadcast manufacturers have integrated NMOS and Ember+ into their devices to provide smarter and more flexible IP networks for broadcasters. It also increases network security as unified control interfaces reduce the number of services and potential entry points available to nefarious actors.
More information on NMOS visit https://www.amwa.tv/ and for details on Ember+ visit https://github.com/Lawo/ember-plus/wiki. For more details about Tieline codecs and NMOS/Ember+ integration contact Tieline sales:
- For USA, Canada & Latin America contact: sales@tieline.com
- For Australia and International: info@tieline.com
