34 l January 2014
www.psneurope.com broadcastfeature
“There is a fixed format for sending audio, which can be stereo on tracks one and two, Dolby E on three and four and different languages in stereo on five and six ”
Recently published QC ‘periodic table from the EBU in-house magazine
areas and replacing commercial management system products. Pallett says Telestream’s
UNITED KINGDOM QC: Quite Clever
IN AN increasingly global broadcasting market, where live events are transmitted round the world and programmes sold to many different countries, consistency in quality control (QC) and quality assurance (QA), to show that material conforms to recognised standards, is more important than ever. In recent years manufacturers have been developing test and measurement (T&M) equipment – the basis for QC/QA systems – with new and expanded features to measure, adjust and even correct audio parameters so programmes do not fail acceptance tests. The European Broadcasting Union (EBU) is hoping to build on T&M technology already on the market and harmonise terminology and testing through its ongoing Strategic Programme
John Pallett of Telestream
on QC; during IBC 2013 it published the first version of its QC Criteria (EBU Tech 3363), accompanied by a ‘periodic table’ representation of different tests. The EBU QC criteria cover audio, video, format/bit stream and metadata/other.
The EBU Strategic Group for QC is chaired by Andy Quested, head of technology for BBC HD and Ultra HDTV. “The project began nearly two years ago as a small group but it grew as more people became interested and got involved by email,” explains Quested, speaking in his EBU capacity rather than on behalf of the BBC, although he is leading the broadcaster’s QC project. The result of this input, he says, resulted in a “massive list” of more than 500 tests, which the Strategic Group has spent six months whittling down to something more manageable. “Some of them were
requirements rather than tests,” he comments, “and other tests turned out to be the same as each other but under different names. What we’re working on now is about 160 tests for base band audio and video and
Vantage range of transcoding and workflow processing tools, and other file-based systems, is being used in three ways: to do what had been done before by linear test equipment; to perform QC “in between the file-based steps”, as material is converted into different formats using MXF (Material eXchange Format) or other technologies; and to assess files and make decisions as to how they should be dealt with. Most of the assessment and judgement processes that need to be made, Pallett says, are to do with audio: “File-based QC systems with built-in intelligence are able to open a file and check it complies with set standards but also recognise the structure and instigate changes if necessary. This includes up-mixing a stereo file or downmixing something that is 5.1, as well as detecting different language tracks and unwrapping Dolby E encoded material.” Tom Williams, vice president
(and quite interesting)
Technical standards have been the bedrock of good broadcasting since their origins. But major changes are underway to formulate common tests and move the majority of checks to the beginning of the production chain. Kevin Hilton looks at what this means for broadcasters and T&M equipment manufacturers alike
files containing both sound and vision.” What will come out of all
this for broadcasters, Quested explains, is a first in that everybody will agree on the definition of what is being tested. “For QC vendors it means being able to produce equipment with specific EBU tests, so a programme could be checked on different systems and produce similar results,” he says. John Pallett, director of
product marketing for enterprise products at Telestream, observes that the EBU strategic group has put a lot of effort into determining good and bad programme quality. “It puts structure round software and hardware,” he says. Pallett adds that while “signal-based measurement” is still important, especially for live feeds, file-based QC is spreading into different
of sales and marketing for Audio Precision, says the company’s range of analysers is used to calibrate and test the QC systems that in turn check programme material. “Broadcasters need to know that their metering equipment and various players are working correctly,” he explains. “The big change has been how devices are able to handle digital formats. Our encoded audio tester is designed to look at the actual file but is format agnostic, because there are so many encoded files out there.”
Amberfin produces ingest,
transcoding and play-back/ monitoring software systems that incorporate checking features. Chief technical officer Bruce Devlin comments that there is more need for T&M and QC because of the need to improve “throughput” on the production chain and the fact that material is now “hidden on huge servers”. He also points out that while the terms T&M, QC and QA are often used interchangeable, they are distinct procedures: “It is important to note that T&M generates the data that a QC process uses to make decision that change the QA practises of a facility. T&M is done by software to create data that a combination of software and humans use to
Raphael Samad
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