Sound handling
May 1, 2007 12:00 PM, BY SPENCER RODD
Four ways to manage digital audio files in your broadcast environment.
Technicolor Network Servickes UK uses a Pharos Mediator workfl ow management system in the master control room at it’s multichannel playout facility at Chiswick Park, Lodon.
The increasing affordability of LCD and plasma panels is encouraging television viewers throughout the world to replace CRT-based receivers with larger displays. The quality of digitally delivered 525- and 625-line SD when viewed on a 40in monitor is extraordinarily good and will continue to improve as the industry moves forward with HD.
Larger screens inevitably encourage viewers to invest in surround-sound equipment, bringing the cinema experience direct to their homes. This in turn requires broadcasters to deliver multiple signal channels, transmitting Dolby 5.1 surround as a digital stream. The increasing globalization of program delivery has added to the requirement for multichannel audio by expanding demand for multilanguage soundtracks. Through case studies, this article will look at the various ways in which audio is handled in modern file-based broadcast environments.
Centralized audio storage
A digital server system forms the central audio storage resource at the Broadcast Center in White City, London, one of Europe's most modern playout facilities. Designed specifically for broadcast and post-production applications, it captures and files programs using an integral SQL database.
Pharos Pilot unifi ed control system at Channel Four UK
Audio files can be located quickly and used in playlists or played directly to air. Applications include radio announcements, program store-and-forward, automated voice-over playout and multichannel audio playout. A record screen enables announcers or voice-over artists to make their own recordings. Audio files required for playout can be recorded automatically from DAT or CD using the ingest screen.
Multiple tracks on one tape can be recorded in a batch, speeding up the process. Broadcast wave (BWAV) files can also be copied directly on to the audio server and then logged in the database. Files can be copied from server to server automatically or manually, allowing configuration for full one-to-one redundancy.
The server brings major advantages to production and playout operations, and supersedes traditional audiotape, cartridge-based and MiniDisc play-in devices. Recordings can be made to the server without having to load, label and archive individual tapes, cartridges and discs. Audio content held on the server can be accessed rapidly using its integral database, giving all the benefits of a massive library without the risk of items being lost in transit from shelves of individually archived storage media. The system also provides levels of redundancy not normally associated with traditional magnetic media.
Stored content is accessible from the continuity booths and automation-driven playout suites throughout the facility. The system's primary function is to store speech clips for end-credit and other program-junction announcements. As channels evolve their output content, the system can also be used to store other audio-based objects, such as music or effects. Each automated playout channel has access to at least one replay port from the server cluster. The continuity booths are equipped for record and replay.
The audio server is fully integrated into OmniBus automation systems chosen for playout operations and normally plays prescheduled clips to air without manual intervention. It can also be accessed under direct control by playout directors, retaining at all times their freedom to initiate an immediate manual audio playout for highly reactive channels, such as BBC One and BBC World.
A major advantage of the production workflow is its ability to populate the database directly from individual channel planning schedules. Very little metadata needs to be keyed as part of the authoring process. Recording productivity is therefore high, and expensive vocal talent costs are minimal.
Voice-over recording
UK commercial network ITV uses a server-based digital audio system as the core of its voice-over recording facilities at the Southern Transmission Centre on London's South Bank. This resource enables voice-over presenters to create audio interstitials for the ITV1 network and regions, as well as for ITV2 and ITV3, which are all played out under the control of the transmission automation system. The installation consists of three audio servers integrated to a database-driven media manager.
ITV's first digital audio server, installed in 2002, replaced a PC-based audio recorder that served ITV1 and ITV2. The three-server system has a total of 12 audio ports that are routed to the individual regional destinations served by the transmission facility. In addition, files destined for the northern regions are automatically sent by FTP to the ITV Northern Transmission Centre in Leeds for playout. Similarly, voice-overs recorded for HTV Wales in Cardiff, on a standalone digital audio server, are sent automatically in FTP format to London for playout.
ITV uses a Pharos Audio Server for voice-overs at its Southern Transmission Centre on London’s South Bank.
The three servers are mirrored, so each of the three voice-over booths is able to record items for any region. The items are then automatically copied between servers.
Operators in each booth have access to a make-list and fingertip control of everything needed for fast recording and audition. Each voice-over is recorded in stereo as a 48kHz 16-bit BWAV file, including metadata.
The record workstation installed at ITV is easy to use, an essential requirement when a typical session may require more than 100 announcements spread across all services. The presentation suites all have the ability to preview recorded announcements via direct playback workstation. The software is modular and highly logical, allowing ITV staff to maintain and configure the system.
The audio server allows recordings to be made without having to trace, load, label, back-up or archive individual tapes, cartridges and discs. Stored content can be accessed rapidly using the integral database.
The server can also be configured to provide levels of redundancy not normally associated with traditional magnetic media. BWAV files can be copied directly on to the audio server and then logged in the database. Files can be copied from server to server automatically or manually, allowing configuration for full one-to-one redundancy.
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