Networked Audio: Current Developments & Perspectives for the Broadcast Market

Transcription

1 Tonmeistertagung 2010: Networked Audio: Current Developments & Perspectives for the Broadcast Market Andreas Hildebrand, Senior Product Manager ALC NetworX GmbH, Munich TMT

2 Presentation Overview Introduction Requirements for broadcasting applications Overview on existing solutions Current developments I: Introduction to AVB Benefits of IP-based solutions Current developments II: Introduction to RAVENNA Summary TMT

3 Why Networked Audio? Availability / reliability: network technology is the backbone of all kinds of communication business world-wide Standards: protocols & technology based on world-wide standards Flexibility: allows easy and fast configuration changes Versatility: different type of signals & multiple services can share the same network Accessibility: signals can potentially be accessed anywhere within the network Scalability: performance / capacity can scale with capabilities of network technology & infrastructure Cost advantage: cables / switches less expensive, available in large volume quantities Maintenance effort: network infrastructure cheaper to operate and maintain TMT

4 Fields of Application in Broadcast Environment In-house applications Signal management in central facilities Distribution between studios & production areas Feed distribution to journalist desktops WAN applications Connection between regional studios Inter-facility links across corporate networks STLs WAN connections OB van applications Hook-up to venue / event installation (sports stadium, hallmark events live concerts etc.) TMT

5 Requirements in Broadcast Applications Criteria for suitability in broadcast applications: Operation in existing environment Existing network infrastructure Structured network topology Shared traffic Scalability Latency lower single-digits milliseconds Variable sample rates and data formats High availablility / redundancy - seamless fail-over Native PC support WAN capabilities Non-proprietary solution Based on standards TMT

6 Market Overview - Existing solutions SuperMac (AES 50) / HyperMac based on CAT5 or fiber Proprietary point-to-point connection, no network at all Layer 1 based on physical layer of Ethernet (copper or optical) always proprietary technology, examples: A-Net, Rocknet, SoundWeb, OptoCore, MediorNet et al. Layer 2 - based on Ethernet data link layer mostly proprietary technology with black box licensing model, examples: EtherSound, CobraNet et al. Layer 3 based on IP utilizes common internet technology (addressing & routing schemes, streaming formats etc.) examples: Livewire, Q-LAN, Dante et al. other (non-relevant) technologies: VisiBlu / FlexIP / PYKO and all IP codec solutions (APT, Mayah, Qbit, Prodys et al) TMT

7 Existing solutions compared to OSI layer model OSI Layer A-Net EtherSound CobraNet Application Livewire Dante Presentation Session RTP RTP Transport UDP UDP Network IP IP Data Link Ethernet Ethernet Ethernet Ethernet Physical Copper Copper / Fiber Copper / Fiber Copper / Fiber Copper / Fiber TMT

8 Existing solutions vs. Broadcast Requirements A-Net EtherSound CobraNet Livewire Dante Layer 1 2a 2b 3 3 Topology P-t-P (Star) Daisy Chain Structured Structured Structured Routable No No No No Potentially Network equipment Cat 5 Ethernet Ethernet LAN LAN Shared network No No (yes) Yes Yes Scalable No (64 ch) No (64 ch) No (64 ch) Yes (32767 ch) Yes Latency Low (800 µs) Very low (125 µs) Medium (1.3 ~ 5.3 ms) Medium (> 1 ms) Low / variable (< 1 ms) Sample rates 1 common 48 / 96 khz 48 / 96 khz 48 khz (fixed) Variable Data format 24 bit 24 bit 16 / 20 / 24 bit 24 bit Variable Redundancy No Ring STP STP Dual NIC PC support No PCI card PCI card Virtual / PCI Virtual / PCI Transport protocol Proprietary Proprietary Proprietary RTP RTP Open Standard No No No No No TMT

9 Current Developments I Ethernet AVB: Audio Video Bridging for real-time sensitive media data TMT

10 Ethernet AVB Ethernet AVB is not a solution It s a set of protocol standards which enable the building of an Audio Video Bridging network for reliable transport of real-time sensitive media data TMT

11 Ethernet AVB IEEE (Ethernet) protocol enhancements: AS precision time protocol Qat stream reservation protocol (Clause 11 amendment to Q 1 ) Qav 2 traffic shaping (Clause 12 amendment to Q) BA interoperability profiles New transport protocols for AVB-enabled networks: 1722 Layer 2 transport protocol and payload format definition 1733 Layer 3 transport protocol (RTCP extension) configuration & control protocol for 1722 devices Standards approval expected between mid 2011 ~ mid IEEE Standard for Local and Metropolitan Area Networks - Virtual Bridged Local Area Networks 2 approved on Dec 10th, 2009 TMT

12 Ethernet AVB IEEE AS timing & synchronization (gptp): Simplified subset of IEEE 1588 PTP, based on transparent clock model Time distribution w/ accuracy of ± 500 ns between any two nodes IEEE Qat stream reservation: Allows reservation of up to 75% of available link bandwidth for AVB traffic Guarantees end-to-end availability of link bandwidth for individual streams TMT

13 Ethernet AVB IEEE Qav queuing and forwarding: Defines sharing behavior of a link w/ respect to isochronous (AVB) and asynchronous (best effort) traffic flows Defines two AVB traffic classes: A & B with max. link latency of 2 and 10 ms 1 TMT

14 Ethernet AVB IEEE 1722 layer 2 transport protocol: Defines a new Ethertype frame for protocol identification (AVBTP = 0x88B5) Frame format and payload types derived from IEC (as used for IEEE 1394 aka Firewire) Includes presentation time stamps with reference to AS time Media clock to be recovered from (reference) media stream IEEE device configuration & control: Defines device discovery, device enumeration, connection management and device control for IEEE 1722 based devices First draft w/ simple specification available Utilizes zeroconf for device discovery Some companies have already begun development of their own (proprietary) protocol suites (e.g. Harman: HiQnet, Apple: AV/C) TMT

15 Ethernet AVB AVB system design: An AVB system consists of a time grandmaster, talkers, listeners and switches All devices, which support AVB functionality, form an AVB cloud Streams can only be distributed within an AVB cloud TMT

16 Ethernet AVB AVB system design: An AVB system consists of a time grandmaster, talkers, listeners and switches All devices, which support AVB functionality, form an AVB cloud Streams can only be distributed within an AVB cloud A stream can be routed across a max. of 7 hops, which would guarantee a max. latency of 2 ms end-to-end. TMT

17 Ethernet AVB Pros & Cons + Guaranteed fixed latency (2 ms) + Bandwidth reservation through admission control scheme + No dedicated network required, traffic sharing possible + Works with different sample rates & data formats + Channel capacity scales with network infrastructure + Open technology standard: Plumbing protocols part of IEEE standardization, 1722 data formats compatible w/ 1394 Firewire format + Supported by different manufacturers o In-band clock distribution, common house clock with separate reference stream o Presentation time concept Operates only within LAN segments, not routable Requires new network infrastructure, cannot operate on legacy environment PC integration with dedicated hardware only Failover / redundancy not specifically addressed TMT

18 IP Networking Why IP-based Networking? Reliability, flexibility, versatility, accessibility, scalability, cost advantage, maintenance efficiency, Availability: IP-capable network equipment and infrastructure readily available and widely deployed WAN capability: content can be routed across WAN connections without technology change Convergence: PCs can participate on the network without sound cards Based on standards: IP standard protocols (the internet protocols ) are widely supported (e.g. RTP/RTCP, RTSP, IGMP, SDP, DHCP, DNS etc.) Future-proof: IP-based services will grow into all areas of communication TMT

19 Current Developments II The IP-based Real-Time Media Network TMT

20 RAVENNA Key Features: A layer 3 (IP) solution Can operate on most existing network infrastructures Allows phase-accurate distribution of media clocks Supports concurrent operation of multiple media clocks and formats Full bit transparency with all media formats Allows low latency for real-time critical applications Supports QoS for reliable data transfer Capacity scales with underlying network infrastructure Supports distribution and synchronization across network segments Full network redundancy support TMT

21 Basic Components: GPS Ext. Reference Sync Master Audio I/O Node IP net (LAN) Node Audio I/O Audio I/O Node Node Audio I/O TMT

22 Redundancy Scheme: GPS GPS Ext. Reference Sync Master Sync Master 2 Ext. Reference Audio I/O Node IP IP net (LAN) Node Audio I/O Audio I/O Node Node Audio I/O TMT

23 An open technology platform: Based on technology publically available Utilizes standard protocols Designed to work on existing networks No proprietary licensing policy Open partnership model Current RAVENNA partners: TMT

24 Standards / Technologies utilized: Streaming is based on RTP/AVP as defined in RFC 3550 / 3551 Supported payload formats: L16 /48 L24/192 AES3 my be encapsulated as MPEG stream (RFC 2250) Both unicast and multicast operation supported QoS: DiffServ (priority traffic classes vs. best effort traffic) RTSP / SDP for connection management Time synchronization via PTPv2 (IEEE ) DHCP / DNS or ZeroConf for device configuration / service advertisement http server suggested for functional device configuration TMT

25 Summary A variety of networked audio solutions is existing Most solutions use layer 1 or layer 2 techniques Most solutions are dedicated to specific fields of applications (mostly live audio & installed sound) All existing solutions are based on proprietary technology or protocols All solutions are based on licensing models Qualifying criteria for Broadcast application: Open technology standards Scalability Integration into existing infrastructures WAN capabilities AVB offers specific benefits, but requires complete change of infrastructure Best match for live audio applications RAVENNA as layer 3-based technology most suitable for Broadcast application TMT

26 Andreas Hildebrand Senior Product Manager Contact information: ALC NetworX GmbH Am Loferfeld Munich Fon: +49 (89) Fax: +49 (89) TMT