TECHNOLOGY FOCUS LOUDNESS METERING Expert Witness
Martin O’Donnell of HHB gives his views on the transition to R128 and the importance of picking the right product for the job.
Martin O’Donnell
One important factor is adoption, and getting agreement from a critical mass of broadcasters in a territory certainly helps improve the odds of making it happen. The UK’s R128 adoption journey
AS TV watchers and radio listeners we have all reached for the volume control on detecting an unacceptable jump in loudness between programmes. These can arise because traditional broadcast audio delivery standards are based on meters that measure electrical level and not loudness. Loudness is the sound level we actually ‘hear’ and if all audio was mixed to the same loudness measure we would eliminate these perceived variations. The benefit of switching to loudness metering is clear – it takes us closer to emulating the best measurement tool we know: the human ear. Loudness metering is not a new
concept –Dolby introduced the LM100 Loudness Meter in 2003 and HHB has many happy customers using it. But in 2010 Europe took a big step forward when the EBU PLOUD Group – an expert collective comprising mainly broadcasters and loudness equipment manufacturers – published its Loudness Recommendation R128, which explained how broadcasters could measure and normalise audio using loudness meters instead of peak meters (PPMs). The manufacturers took R128 and implemented an ‘EBU mode’ on their meters so that sound engineers across Europe could mix to R128 and be confident of loudness compliance between makes and models. Job done, well almost. There are a number of drivers that
influence when (and even if ) a European broadcaster will implement a new audio recommendation into their workflows.
30 February 2014
began in 2011 with the creation of the DPP (Digital Production Partnership) – a body formed by the BBC, ITV, and Channel 4, and including representation from Sky, Channel 5, S4C, UKTV, and BT Sport. Its aim was to help the TV industry transition from tape to a fully digital file-based production model. In 2012 the DPP introduced a new file- based technical standard to which they added R128 audio compliance in October 2013. At IBC 2013 the DPP explained that BBC, ITV, and Channel 4 would move to this file-based programme delivery specification from 1 October 2014 with BSkyB, Channel 5, and BT Sport sharing this aspiration. At HHB we are seeing R128 come of age in the UK as broadcasters and content producers transition their operations towards this new file-based delivery environment. R128 is applicable to all areas of
audio production. Some environments require hardware solutions, others are best solved with software, and applications can be real time or file based. Picking the right product for the job is essential and the following few paragraphs give some examples of the technologies HHB is deploying. For standalone hardware metering
the TC Electronic TM9 TouchMonitor is very popular and probably the most capable, flexible, and configurable metering platform available with SDI, AES, and analogue audio interfacing. Recent developments have included BLITS and timecode logging. DK-Technologies DK1, 2, and 5, and RTW TM3 are also popular choices. For audio and video post-production
applications, Nugen Audio has four complementary software products. First up is VisLM H – a loudness and true peak meter that runs standalone or as a plug-in with timecode logging. Use it while you record and mix. Then there is LM-Correct – intuitive, fast, and accurate. Measure key loudness parameters of a wav file faster than real time with the option to correct against target values to ensure R128 compliance. Next is ISL – a true peak limiter that allows you to get on with
your audio production while it takes care of your true peaks. It is well respected sonically so is equally at home in a music recording and production environment. Finally, LMB is a loudness management batch file processor which can handle MXF and wav. Measure files, correct to predefined criteria, and produce detailed XML logs quickly and automatically. It can be run locally or on a server with a drag-and- drop interface or via a browser and hot folder. This is an ideal way to legalise legacy archived content or new material
“At HHB we are seeing
R128 come of age in the UK as broadcasters and content producers transition their
operations towards this new file-based delivery environment.”
Martin O’Donnell
arriving from external sources: a turbo- charged LM-Correct. As an alternative to VisLM-H we also have installations running TC Electronic’s LM6 loudness radar and the Dolby Media Meter 2. For transmission and archive tape
transfer the TC Electronic DB6 is an expandable 1U intelligent processor equipped with SDI I/O, dual power supplies, hardware bypass, GPIO, and logging. It will measure and correct loudness and true peak in real time to R128. Features include an automatic stereo-to-surround Upmix for the smooth transition of (legacy) stereo material into a surround sound transmission environment. It can also be used when transferring/ingesting from videotape to legalise the content to
Expert Witness
Martin O’Donnell is director of sales at HHB. The company will be displaying its range of loudness products at BVE 2014 in London on 25-27 February. For further information and insight on loudness and anything pro audio visit the HHB website or take a look at the company’s current Pro Audio Report which examines the technical aspects of the new DPP delivery standard and EBU R128 in more detail. To request a copy call +44 (0)20 8962 5000 or visit the website.
www.hhb.co.uk
www.audiomedia.com
R128 and Upmix to surround if required. The Junger T*AP is also a candidate in similar applications. For a complete audio monitoring
solution in an OB vehicle, ingest suite or master control there is the Wohler AMP2-16V-M. The 2U unit comes with SDI, AES, analogue, and optical audio connectivity. Other features include a configurable loudness metering page, support for SMPTE2020 metadata, and the ability to display all 16 channels of embedded audio alongside the SDI picture, plus high-quality built-in loudspeaker monitoring. This is a comprehensive and impressive AMU. Dolby E, D, and DD+ decoding is optional. Last up is the Dolby DP580, a 1U
Professional Reference Decoder with ASI/SDI, MPEG 2, AES, and HDMI inputs. This handles all Dolby formats and gives broadcasters the ability to perform loudness monitoring with logging at any point in their broadcast chain from playout to off-air. The HDMI input also opens up applications in the games industry – where loudness is beginning to gain traction – enabling game producers to test the HDMI output of their consoles. The list above is not exhaustive and
HHB continues to work alongside the leading manufacturers of loudness products. We all know that producing high-quality audio is a rewarding challenge that requires the right tools and experience combined with superhuman craft skills – yes, even our video colleagues will acknowledge this during a quiet fireside chat. EBU R128 does represent a significant change in the way we measure audio but do not be alarmed – if you have been creating dynamic, wide-ranging content with PPMs it is likely you will be spot on with R128.
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