Jands showcased an operational audio video bridging (AVB) system at the Integrate show in Sydney recently.
Ethernet AVB or audio video bridging is a common name for a set of IEEE standards that ensure the transmission of high quality streaming audio and video over a standard Ethernet connection. The audio/video bridging standards were created through a consortium of industry experts, which were ratified and accepted by the IEEE industry standards body.
Instead of just being another proprietary non-standard protocol that floats on top of the Ethernet layers, AVB is the Ethernet. The big difference between AVB and previous solutions for network streamed audio/video is that the IEEE controls the Ethernet standards, which allows for the specifications of not just the endpoints, but more importantly the switches.
This allows an entire network to be designed to accommodate audio and video, with compatibility between AVB devices that are made by different manufacturers.
The standards specify a means to provide time synchronised low latency (a maximum of 2ms across 7 switch hops) audio and video over standard CAT5e cable. The majority of the bandwidth across the network is reserved to carry audio and video, and to guarantee the arrival of a signal.
Bandwidth is reserved and defended throughout the network by the switches to transport the large amount of information required by both audio and video across a network.
By default the switch will reserve and defend 75% of network bandwidth to be exclusively used for AVB media, both audio and video, which will guarantee precisely synchronised audio/video without interruption from non-time sensitive data and communication, such as email or control protocol traffic.
Each audio/video sample is time-stamped with exactly what time to play, and all AVB devices are synchronised to a common clock known as the Grand Master clock. This allows for the synchronisation of multiple streams of audio and video to be rendered at the correct time with respect to each other.
An AVB network inherently supports multiple simultaneous sample rates and (sample) clock sources, which allow video and audio streams to be synchronised even though they travel on different paths with different sample rates.
Key features of Jands’ operational AVB system:
- Compliant Ethernet switch and a starting audio point and an end audio point, or points
- Netgear/BSS GS724T switch: 24-port, 2Gbps per port, fully managed network switch
- Start and end points are dbx System Core Matrix DSP devices
- dbx SC 32 and 64 devices can handle up to 118 channels of audio arriving into each processor
- Can output up to 32 or 64 channels respectively back onto the AVB network
- Each SC device contains 4 (SC32) or 8 (SC64) SHARC DSP chips to handle this amount of channel matrixing
- Semi flexible audio processing available in the shape of Automatic Feedback Suppressors, Ambient Noise Compensators, Gates, Compressors and multiband Parametric Eq
Jands is a leading Australian distributor of professional audio equipment as well as lighting and staging systems.