What is RAVENNA?

Ravenna Audio over IP

OPEN AUDIO OVER IP

RAVENNA is an open solution for transmitting audio over IP. Designed to meet the exacting standards of the Broadcast industry, RAVENNA delivers high-quality, multi-channel audio over a standard IT network.

RAVENNA why audio over IP?

Why Audio over IP?

There are primarily two reasons why users consider using Audio over IP today:

  1. Flexibility in signal routing
  2. Low cost - the small audio industry ‘borrows’ technology from the much larger IT industry that has already been debugged and commoditised over many years, this greatly reduces the cost of devices such as network switches.


Traditional audio distribution is often implemented using large cross-point switchers or patch bays. These are specialised and expensive devices which take a long time to install and maintain. They do have the advantage of minimal delay and do not change the signal content or format.

 

A network system can be rapidly connected together using standard off-the-shelf parts which are much more compact and can be implemented in either a centralised or decentralised fashion.

 

As network systems originally had no need to consider real-time transmission of data (files were re-assembled from a collection of packets after they had all arrived), there were some disadvantages to overcome. These are largely done now and the advantage of a cheap scalable infrastructure that may already exist in many facilities is becoming too persuasive too ignore.

USER BENEFITS

RAVENNA user benefits

FEATURES

Standard Network Technology

RAVENNA leverages standard network technology, the performance of a RAVENNA system improves with the quality of the network infrastructure.

Using a new or existing network infrastructure, RAVENNA is idealy suited to installed audio environments such as Broadcast studios, Live sound reinforcement, Corporate AV systems and Education facilities which require efficient and flexible audio distribution.

IP Technology (OSI Layer-3)

As an IP-based solution, RAVENNA is based on protocol levels on or above layer 3 of the OSI reference model. IP can be transported on virtually any LAN and is used as the base layer for communication across WAN connections (including the internet). Although Ethernet will be deployed in most cases as underlying data link layer, IP is in general infrastructure-agnostic and can be used on virtually any network technology and topology.

Low-Latency

RAVENNA offers a highly flexible latency scheme, ranging from very low latency numbers in the sub-milliseconds area up to latency numbers large enough to suit the constraints of a WAN infrastructure. Unlike in other solutions, RAVENNA does not force the latency to system-wide defaults. In fact, the latency can be set for any stream individually and depends on a number of factors.

Phase-Accurate Synchronisation

Professional audio applications demand tight synchronization between all devices and audio streams. While playback synchronization in most applications requires sample accuracy, it has been the goal for RAVENNA to optionally provide superior performance by providing phase-accurate synchronization of media clocks according to AES-11; this would render the separate distribution of a reference word clock throughout the facility or venue obsolete.

In RAVENNA, synchronization across all nodes is achieved through IEEE1588-2008 (also referred to as Precision Time Protocol or PTPv2), another standard protocol which can be operated on IP. PTPv2 provides means for synchronizing local clocks to a precision in the lower nanoseconds range with reference to a related master clock - provided that all participating switches natively support PTPv2. But even without native PTP support, the achievable precision - while varying depending on size and bandwidth utilization of the network - will be more than sufficient to reach sample accurate synchronization across all nodes. Sample-accurate synchronization can even be reached across WAN connections, when local master clocks are synchronized to GPS as a common time domain reference.

Flexible Profiles (Multi-Format Support)

RAVENNA Profiles enable users to customise the audio stream for their application. Based on standard networking technology, RAVENNA can support a variety of audio formats within its payload.

RAVENNA supports a variety of different data formats used in professional environment. For audio applications, 16 and 24-bit integer as well as 32-bit full bit-transparent AES/EBU data formats in combination with all relevant sampling rates (32 … 192 kHz) are supported. Since RTP is used as transport protocol, virtually any desired data format (i.e. 32-bit floating point, DSD and DXD high-res formats and others) can be transported across a RAVENNA network. This is not limited to audio data, but includes video data as well as control data. Although only one data format is permitted per individual stream, different streams with different data formats can coexist on the same network concurrently.

Since no sample rate or format conversion is required, RAVENNA offers full bit transparency. This ensures 100% preservation of the original signal content. In certain applications this is not only a quality feature but a mandatory prerequisite (e.g. with encoded data streams like Dolby E®).

Full Redundancy

Although a modern network infrastructure can offer a high level of transport security and reliable 24/7 operation, a RAVENNA setup can be configured in a way to provide full network redundancy. Each RAVENNA device may optionally exhibit two independent network interfaces, which can be connected to independent physical networks. By duplicating any outgoing stream to both network links, any destination device will receive full stream data on both network interfaces independently. If data from one link is corrupted or one network link fails completely, the uncorrupted data is still present on the other link. An internal mechanism ensures flawless and uninterrupted continuation of play-out.