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36 l January 2014


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make good QC decisions that are then used to change the operational practise of software transcoders, hardware encoders and human editors. QA ensures an organisation can continually improve the quality of its output.” Robert Millis, senior product


manager for monitoring solutions at Harris Broadcast, calls it “one of the most significant drivers” in the move to file-based QC testing has been loudness. “With the file you are able to get the most accurate loudness measurement by looking at the entire programme from beginning to end,” he comments. “If correction is needed then the highest quality tools can be applied to adjust the loudness levels while maintaining dynamic range.” John Terrey, vice president of sales with Wohler Technologies, says most of its users are doing some form of loudness measurement and correction. Wohler covers both hardware and software, with the AMP2 and LCM-KRT-OG1 units, for analysis and correction respectively, in the base band domain. WohlerLoudness, based on the RadiantGrid platform with Linear Acoustics’ AERO technology. Terrey observes that the advantage of WohlerLoudness as a file-based system is that material does not have to go back into base band to be analysed.


EBU QC CRITERIA


THE EBU QC tests laid out in Tech 3363 come under one of four main headings: regulatory, absolute, objective and subjective. Loudness is now a priority in both the creation and distribution of programmes. As the forms of loudness regulation vary from country to country, it comes into the absolute category and complies with the appropriate national or regional standard: EBU R128, ITU 1770, ATSC A/85. “If the target is -23 for R128 and something measures -27, then clearly it’s outside the spec and the metadata is incorrect,” comments Andy Quested, chair of the EBU Strategic Group on QC. He says the tests range from


the relatively simple to the more complicated. “Some can


HHB offers a range of loudness systems, including TC Electronic hardware and Nugen software. Sales director Martin O’Donnell says there is an “acceleration” in both file- based and real-time loudness QC, with requirements for upmixing as well. “We’re seeing more 3G/SDI embedding of audio and a proliferation of products across the hardware, software, real-time and file-based areas,” he says, adding that the new DPP [Digital Production Partnership] specifications are making broadcasters and facilities consider their approach to T&M and QC. O’Donnell says people are looking at the TC Touch Monitor range for real-time environments; these units have a large display for loudness and true peak, suitable for monitoring during a mix. The Nugen range has real-time/true peak capability in the VisLM, which also offers logging, while the LMB (loudness management batch) processor is aimed at fast handling of multiple WAV files. At Jünger Audio, international sales manager Anthony Wilkins says there are now questions to be addressed about interoperability between different formats over networks and the ability to check this. “When you’re networking audio you want the different formats involved to talk to each,” he says. “We’re going to see more of this as IP distribution


Andy Quested


Amberfin ingest, transcoding and playback/monitoring software systems incorporate checking features too Bruce Devlin of Amberfin


increases in broadcasting but the important thing is to make the monitoring and everything else easier, not more complicated.” Jünger Audio produces the M*AP monitoring audio processor, which Wilkins describes as a standalone T&M/QC tool set. This offers


a similar way. Quested reveals that in preparing material for a production about the 1969 moon landing, one person asked for it to be reshot on the grounds of quality. He adds that there are plans to remove all objective tests from the list and move them into either the absolute or subjective groupings. Audio test parameters in


be done by ear and eye but in many cases it’s the interpretation that is the difficult thing,” Quested explains. “It’s about context as much as technical standards. If someone is interviewing a fish underwater then the background noise is fine because it is a creative choice. If it’s a serious journalist talking to the Prime Minister then it’s probably not OK.” Archive footage is judged in


addition to loudness include: audio bit depth, channel count, digital clipping, coding syntax, service correlation, dropouts, duration, peaks, phase reversal, sample rate, and audio test tones. Tests also exist in one or more layers: wrapper, bit-stream, base band and crosscheck. The EBU Strategic Group on QC is currently working on the batches of tests and hopes to publish a finished list in April or May.


monitoring control and SDI support as well as loudness measurement; Wilkins points out that an important feature is comprehensive Dolby metadata emulation to handle 5.1 and other surround formats. At Dolby itself Mark Pascoe, senior technical marketing manager, comments that “the requirements for audio monitoring should not have changed significantly due to the growth of file-based operations and embedded audio”. He adds: “It will always be better to listen to audio rather than not, but regrettably, with the number of services now delivered over multiple platforms to multiple devices, and the space and resource generally available to carry out that process, it is simply not possible to monitor everything at the time of delivery. This, of course, will inevitably increase our reliance on T&M equipment and QC processes; the former to make sure that the systems through which content flows are consistent and of a consistently high quality and the latter to ensure that content delivered through those systems both fits and fills those pipes.” Mike Kahsnitz, head of


product management at RTW, sees QC/T&M as a “growing issue”, with broadcasters looking to provide better quality audio in different formats over a variety of distribution channels. “To succeed I can see human operated QA and a well-aligned system in the distribution and conversion. Fully ‘automated’ operation according to the principle of ‘let the transmission limiter take care of that’ should not be the desired workflow. That would work technically but certainly not match the requirement of improved


sound quality. And don’t forget to be prepared to check for the right metadata transmitted along with the audio.” In the new vision for QC the


metadata will itself be checked and scrutinised, most likely at the end of the chain to ensure that the tests carried out earlier on are correct and that the file is in the right format. Even with all the checks and balances, adjustments might still have to be made at a later stage, something that Emotion Systems is now addressing. The UK developer specialises in software for file-based broadcasting; its first product was the eFF (Emotion File Finish) program for measuring, reporting on and correcting loudness in media files. Emotion Systems has now


moved into other areas of QC with eRAP; as the name implies it is designed to open (‘unwrap’) files, carry out any changes and then re-wrap them. Business development director Raphael Samad comments that a big issue for broadcasters and play-out facilities is ensuring that the layout of audio in media files is constant. “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,” Samad explains. “Facilities receive material from different contributors and the configuration can vary, so there is the need to shuffle and/or copy the tracks to achieve the right layout for play-out.” As well as creating a common


set of definitions for QC, the EBU Strategic Programme is keen that products from all manufacturers in the market comply with the criteria and so are available to all facilities








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