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Audio over IP

Audio over IP. By Meenakshi Singhvi Station Engineer. How Ethernet is Changing Broadcast Infrastructure. Introduction. In Radio broadcasting setup audio mixing console is the heart of the system and remained relatively unchanged for more than twenty years.

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Audio over IP

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  1. Audio over IP By Meenakshi Singhvi Station Engineer How Ethernet is Changing Broadcast Infrastructure

  2. Introduction • In Radio broadcasting setup audio mixing console is the heart of the system and remained relatively unchanged for more than twenty years. • The broadcast studios of today rely on expensive and proprietary communication means in order to network the large number of studio devices. • Originally, source equipment connected to stand-alone mixing consoles with discrete analog signals.

  3. Introduction • Later, the preferred method of interconnection became AES/EBU digital. • Using modern computer networking equipment, it is now possible to build robust Networks capable of transporting digital media signals throughout a complete studio facility. • Introducing an IP-based network in the studio environment is becoming an increasingly attractive solution.

  4. Sources are different now  • Days have gone of playing from carts, vinyl, cassette and reel tape in a typical broadcast. • Most program audio is now recorded, edited and played out of a PC system. • While consoles remain much the same, the PC has quietly taken center stage in today’s radio studio.

  5. Sources are different now  • Traditional consoles handle PC audio the same as any discrete source, hindering potential intercommunication that might enhance accuracy and efficiency. • Instead of using analog or AES/EBU audio as the interconnection standard, it is believed that all broadcast audio systems of the future will use networked Ethernet to provide a much more flexible and cost-effective alternative to console systems used today.

  6. Why Ethernet

  7. Ethernet is so much better. • Very active development. • 500+ channels (on Gigabit link). • Bi-directional traffic. • Easy RJ-45 connectors. • All the data capability we need. • Ubiquitous computer standard. • Routing, networking: inherent (low cost).

  8. Today’s Ethernet… • 100 Mbps to 1 Gbit. • CAT 5e/6 Copper or Optical Fiber. • Switched star, not shared – No collisions. • Full-duplex. • Priority for audio Quality-of-Service. • Multicast allows one-to-many. … is not your grandfather’s Ethernet!

  9. Enormous Capacity

  10. Ethernet is commonplace Radio facilities are fully networked. Almost.

  11. IP-based audio systems represent the future.

  12. IP Audio Systems • Today, IP-Audio is making traditional audio distribution infrastructure as obsolete as the cart machine. • These systems use the same IP technology that powers business data networks. • IP-Audio eliminates the discrete-wiring model used since the dawn of radio.

  13. What is IP-Audio Routing • It’s not Internet audio! • Uses switched Ethernet • 48 kHz / 24-bit uncompressed audio • Delivers real-time audio with guaranteed QoS • Routes machine logic, PAD, custom backfeedsalong with audio sourceElement

  14. Why are IP-Audio Networks considered to be the future of the broadcast plant? • IP Audio networks enable broadcasters to cut costs by using a common transport mechanism for audio, control, messaging, and other data traffic such as files and e-mail and VoIP phones.

  15. Why are IP-Audio Networks considered to be the future of the broadcast plant? • IP-Audio networks provide broadcasters the flexibility to grow and change at will. Traditional systems lack this flexible connectivity.

  16. IP-Audio Defined • What is IP-Audio? • Digital audio over Ethernet • Designed to replace bulky cables • Provides converged audio and data paths • Enables source sharing between multiple studios, stages or locations

  17. IP-Audio, Like VoIP? “Isn’t that like VoIP?” • IP-Audio Differences: • High bit-rate, full fidelity • Isochronous and multi-channel • High-reliability • Guaranteed QoS • Low latency • No packet loss • Linear, uncompressed audio

  18. Why not AES/EBU? • Dead end: No development for 15 years. • One channel, one way. • Soldered XLR connectors. • No significant data capability. • Low volume, expensive. • Routing requires complex hardware.

  19. Standard Ethernet Protocols • QoS (Quality of Service) • STP (Spanning Tree Protocol) • IGMP (Internet Group Management Protocol) • UDP (User Datagram Protocol)

  20. THE FUTURE IS NOW The broadcasting industry is on the verge of an IP-fueled revolution in distribution and infrastructure design

  21. How Audio Routed • Low cost mass market Ethernet switches offer this function. • Since their function is to direct packets from port to port, we can use them to move our signals from whatever source to whatever destination we want. • Simple, flexible, facility-wide audio routing system, almost for free. • Goodbye to racks of distribution amps or expensive proprietary main frame router. • An audio source entered into the system from any point becomes available for any number of receiving destination.

  22. High-Performance Sound Card Replacement • Soundcard emulation driver directly packs / unpacks audio to / from system Ethernet. • No hardware needed. • Balanced I/O with more than 100dB dynamic range, < 0.005% distortion, headroom to +24dBu, etc. • It make excellent multi-channel “soundcards” for professional applications.

  23. High-Performance Sound Card Replacement • Sound card problems such as noise and multiple conversions are avoided-audio remains in digital form from the PC’s files to the network with no alteration or degradation. • With so much audio in radio stations being either played from computers or recorded into computers, it is a tremendous advantage. • Thus lowering cost and eliminating conversion steps.

  24. Fidelity • Internet streams are usually compressed for transmission over public links with limited, variable bandwidth and low reliability. • But in Broadcast Ethernet Networked studio, audio is not compressed- it uses studio grade 48khz/24-bit-PCM encoding. • Dynamic range more than 100dB, <.005% THD, and headroom to +24dbu. • LANs offer a safe, controlled environment, no risk of audio drop-outs from network problems and plenty of bandwidth for many channels of high-quality audio without compression.

  25. Convergence • IP is growing as a universal transport for almost any kind of signal. • It is now in television studios, business teleconferencing, government communications, banking, etc. • PBX companies like Lucent, Nortel, Mitel, Alcatel, and Siemens have plunged into IP transport for their telephone products. • An Ethernet network being used for audio in broadcast studio may be shared with any other data like computer data, telephone, audio, and control on a single network and this will use computer/telephone industry standard wiring.

  26. How IP-Audio works: • An Ethernet switch becomes an audio router. • Advertises audio sources to receivers. • All sources available everywhere.

  27. How IP-Audio works: Audio sources connect to “audio nodes”

  28. How IP-Audio works: Nodes convert audio to uncompressed, 24-bit/48 kHz digital audio, then translate it to packet data

  29. How IP-Audio works: Each audio node input/output is assigned an IP address for identification and routing purposes

  30. How IP-Audio works: Logic ports on each device are connected to GPIO nodes, which convert on/off, tally and other commands to packet data

  31. Nodes in Studios

  32. How IP-Audio works: 301 302 303 To LAN 192.168.2.30 Each audio source is given a channel number. Each node is assigned an IP address for identification and routing purposes

  33. How IP-Audio works: Each node makes its audio and control data available to the network

  34. Studio A Studio B Studio C How IP-Audio works: Each studio’s local Ethernet switch is connected to the other rooms via core switches or daisy-chain

  35. How IP-Audio works: Complete Studio

  36. Network Multiple Studios.

  37. HOW IP-AUDIO WORKS • Compared to traditional multi-line broadcast phone systems, an IP-Audio based system requires only a single Ethernet connection – simplifying installation By integrating IP-Audio interfaces into equipment, installations are greatly simplified

  38. HOW IP-AUDIO WORKS • With an IP-Audio based computer delivery system, audio travels to the network via the computer’s NIC card – without soundcards, multiple audio lines, or D/A/D conversion By integrating IP-Audio interfaces into equipment, installations are greatly simplified

  39. HOW IP-AUDIO WORKS BE, BSI, D.A.V.I.D. Systems, dMarc, Enco, IDC, Netia, Omnia, OMT, Pristine Systems, Prophet Systems, Radio Systems, Synadyne, Telos and Zenon Media have all announced IP-Audio system compatibility

  40. HOW IP-AUDIO WORKS In addition to simplified installation, lower costs – both short and long term – are significant benefits of IP-Audio systems

  41. Audio over Ethernet/IP:Why Is It So Good? • Supported by huge R&D from the computer and telephone worlds. • Common, universal wiring. • As with PCs, volume brings performance, variety, and low-cost. • Learn one system, then you understand audio, phones, and data. • AIR has already invested in huge infrastructure of CAT 6 networked modern PC network at all stations.

  42. Audio over Ethernet/IP needs: • 100% Reliability. • Low Delay. • One-to-many Routing. • Source Advertising.

  43. Reliability • Each node “owns” entire link. • Full Duplex. • Switched. • Cannot exceed link capacity.

  44. Input Port Classify Output Port High-priority Queue Mux Input Port Classify Low-priority Queue Output Section per Port Modern Ethernet’s Priority System. • Lets you combine audio, control, and data traffic on the same network, with no audio dropouts.

  45. Delay- Latency • In broadcast studio, we are very much concerned about the audio delay in the microphone-to-headphone path for live announcers. • Packetizing audio for network transmission causes delay. • Internet audio delay is often multiple seconds because the receiving PCs need long buffers to ride out network problems and the delays inherent in multiple-hop router paths.

  46. Delay- Latency

  47. With fast Ethernet switching on alocal network, it is possible to achieve very low delay.

  48. Delay Problem being solved • Short packet length. Short packets require less buffer time. • Low jitter = small buffers. Low jitter means timely packet delivery. Timely delivery means no buffering required. To achieve low jitter, every node has a sophisticated sync method using an extremely precise PLL.

  49. APPLICATIONS:Interchangeable Studios • For years, broadcasters have built “Mirror” studios for interchangeable use, but… • Taking any room to air as needed presents logistical challenges with traditional hardwired systems. • With its decentralized, shared data approach, IP-Audio networks simplify construction and use of identical studios • Gigabit Ethernet has the capacity to carry hundreds of simultaneous stereo audio channels per link – with audio, logic, and program associated data all traveling the same CAT-6 cable

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