Loudness: What happens now if my work is not compliant?


Jon Schorah TV-Bay Magazine
Read ezine online
Now that loudness is a mandatory requirement in the United States, Europe, and much of the rest of the world, it’s not so much a question of when organizations will begin to comply, but how?
1. Now the standards are in place, what happens now if my work is not compliant?
There are varying repercussions for noncompliance, depending where you work and in which segment of the industry.
For the post-production engineer, if you are not required to deliver loudness-compliant audio, then your main concerns would be international compatibility and downstream correction. If you produce sound for broadcast in a compliant region, then your noncompliant work will either be rejected outright or corrected in a manner beyond your creative control. Because the majority of audio is now moving toward compliance, even if your work makes it to broadcast in its original form, it likely will not compare well to compliant material being broadcast alongside it. If you are required to submit compliant material, a near fail might simply result in correction at ingest, but rejections — along with their associated fees and delays as you rework your submission — are becoming more commonplace.
Broadcasters are in a similar situation. In fact, for broadcasters, voluntary compliance should be a very serious consideration. Anecdotal evidence suggests compliance pays dividends, even in a commercially competitive environment. To the extent that they will choose to stay with a commercial break rather than surfing, consumers genuinely prefer a loudness-compliant channel. Where compliance is required by legislation, then noncompliance can ultimately result in heavy fines.
The drop in loudness-related complaints in the wake of loudness regulation would suggest that, ultimately, the consumer prefers compliant material regardless of legal considerations.
2. Where in the broadcast pipeline should loudness be addressed?
From a technical perspective, there are many places in the audio path that loudness can be addressed, namely playout, ingest, and post-production.
a. Control During Playout
The first approach is playout processing, a scenario in which real-time processors continuously measure and adjust the station output to ensure loudness compliance. Playout processing delivers a technically compliant broadcast, but this method has its drawbacks. For example, in extreme situations, a particularly loud commercial that has been brought into line with real-time processing can actually cause a loudness problem if the programming that follows it is relatively soft. One way to refine this approach is to bypass processing when broadcasting compliant material. Rather than processing the entire broadcast, switch processing on only when material is noncompliant or of unknown origin . The Federal Communications Commission(FCC) in the United States strongly discourages the use of live audio processing to meet loudness requirements.

b. Control at Ingest
A better approach is to ensure compliance at the server level during ingest. This technique can be adapted readily to a modern, file-based environment and works well even with automated batch processing. The downside is that the method can break down during the transition from feature film to television, when loudness range reduction (LRA) requirements come into play. Processing can often change the nature of the sound considerably and can also introduce issues with dialog clarity. That said, a file-based loudness solution can often deliver perfectly acceptable results in cases where the original resources are not available or budgets prohibit anything more involved.

c. Control During Post
By far the best solution — and the one that offers the most creative freedom — is to make a mix loudness-compliant during post-production. This approach integrates loudness into the creative process so that it can be considered alongside other audio variables, ultimately producing audio that satisfies both the consumer and the creative professional.
3. How can loudness be handled at Ingest?
In a file-based environment, checking and adjusting audio for loudness compliance can be readily addressed at ingest using batch processing, which can assess and check files for compliance and even automatically fix audio that is close to target. These corrections are best achieved by a simple loudness offset (with true-peak limiting) that produces compliant material without “treating” the audio with processes that introduce audible artifacts. If material falls outside acceptable limits for the offset approach, then some dynamic scaling (LRA reduction) can also be helpful, although this approach should be used with caution because it encroaches into the creative sphere and might be better suited for post-production.
4. How does loudness fit into the post production workflow?
The best way to employ this approach is to find a loudness-control solution built for the post-production environment, one that offers intuitive loudness tools for audio editors including real-time metering, offline correction, and loudness-compliant limiting.
Visual Loudness Meters
Clear, intuitive loudness metering is the key to delivering high-quality, loudness-compliant audio. Current standards hold the potential for increased dynamic range and contrast. Loudness recommendations are based on a loudness scale designed to correspond to the human ear. With a visual meter, editors can keep an eye on the meter and loudness profile while relying on their trained ears to make most of the decisions.
In the post-production environment, loudness metering software (plug-in or application) can offer a considerable advantage over a stand-alone, real-time hardware meter because it can not only measure a program in its entirety, but it can do it faster than real time. The main target measure of integrated program loudness requires that the loudness be measured over the entire length of the program. For example, making a 30-second edit in a 50-minute documentary will require the entire 50 minutes to be measured again — something of a time issue when using real-time hardware meters. Many nonlinear editors (e.g., Avid Pro Tools® and Media Composer®) allow for faster-than-real-time analysis, and there are also offline file-based tools that can speed up the analysis considerably, avoiding large amounts of unwanted downtime while acquiring measurements. Unlike hardware meters, loudness metering software allows you to get the most out of your nonlinear editor.
True-Peak Limiters
Unlike sample peak limiters, a true-peak limiter can handle the intersample true-peak requirement inherent in all of today’s standards. Loudness normalization deals with loudness jumps and consumer satisfaction issues, but you still need to measure peak levels to avoid distortion in the signal. True-peak level is a measurement of the intersample peak. Maximum peak measurement is specified in order to avoid noticeable clipping and distortion, but because of the way audio is sampled, the real audio level might have gone above the maximum peak level between samples. True-peak level is designed to measure that real level and avoid clipping.
It can be tempting to use sample peak limiters to do the job, but in reality there are no “safe” settings for a sample peak limiter. A sample peak reading can often read as much as 6 dB higher on a true-peak meter, and it is not possible to set a traditional brick-wall limiter (very high ratio and fast attack times) to be safe enough. While you can artificially set limits using PPM, this approach simply introduces another layer of complicationIn reality, the only way to be sure of correct true-peak values is to use a true-peak limiter.
Offline Correction
Once a mix is more or less loudness-compliant, offline tools can speed up the last part of the normalization process. These tools can be used within the editing environment to bring a mix into line quickly, correcting any true-peak overshoots as it goes.
Batch Analysis
Most busy post-production environments will benefit from some form of automated loudness processing. Acting as a rapid fail-safe system and internal QA, a batch processor can automatically assess files for compliance and correct or reject as necessary.
5. Unresolved issues
Because international recommendations are all based upon the same ITU standard, most of us in the industry agree about how to approach loudness control. There are, however, issues that have yet to be resolved, most notably the difference between a 5.1 mix and its corresponding downmix. It is common for the downmix to differ slightly in loudness from the 5.1 mix, but what makes the issue more confusing is that the difference can be in either direction, so a simple offset is not a viable solution. Similar situations arise with dual-language, multi-mono stereo, where a consumer’s television can produce an unexpected 3-dB jump in loudness depending upon the configuration. Reaching for a magic metadata bullet would be one solution, but that solution assumes the metadata is accurate and the appropriate device is capable of reading and responding properly.
Resolving problems with dialog clarity is the next most pressing issue. After loudness jumps, dialog intelligibility above the background audio is the thing consumers complain about most. Whilst it is possible to measure loudness differentials, there is little published research in this area. Even so, it is fairly simple to devise internal guidelines to check for potential problems. Another potential pitfall related to dialog clarity occurs when reducing the dynamic range in film in order to repurpose it for television broadcast. Traditional compression techniques do not take into account the level of the dialog in the original mix, and clarity can suffer as a consequence. Normalizing loudness in either of these situations involves creative decisions that are best applied by the post-production engineer in the context of overall loudness compliance.
6. What’s the future for loudness?
If fewer complaints are any indication, loudness normalization has been a boon for consumers. Now that we have a solid foundation for loudness control, it’s time to dig deeper and refine our solutions. As the loudness market matures, new techniques and considerations are emerging. The aim is for loudness to be a primary consideration during production. As tools improve, we’ll use loudness parameters and transferable, objective measures to check whether audio is not only compliant, but also target-appropriate. Audio engineers will use these same tools to produce programming that better satisfies the myriad different creative and consumer demands.

Tags: iss077 | loudness | not compliant | Jon Schorah | NUGEN audio | standards | control during ingest | limiting | post production | Jon Schorah
Contributing Author Jon Schorah

Read this article in the tv-bay digital magazine
Article Copyright tv-bay limited. All trademarks recognised.
Reproduction of the content strictly prohibited without written consent.

Related Interviews
  • VisLM Loudness Meter update from Nugen Audio at IBC 2019

    VisLM Loudness Meter update from Nugen Audio at IBC 2019

  • Nugen Audio Loudness Meter, Halo Upmix and Halo Downmix at NAB 2018

    Nugen Audio Loudness Meter, Halo Upmix and Halo Downmix at NAB 2018

  • Nugen Audio Loudness Toolkit at BVE 2016

    Nugen Audio Loudness Toolkit at BVE 2016

  • NUGEN Audio: Loudness Toolkit at NAB 2013

    NUGEN Audio: Loudness Toolkit at NAB 2013

  • Product Updates to SAM-Q including MADI & Loudness and PAM-IP updates from TSL Products at IBC 2019

    Product Updates to SAM-Q including MADI & Loudness and PAM-IP updates from TSL Products at IBC 2019

  • NUGEN Loudness Toolkit at NAB 2015

    NUGEN Loudness Toolkit at NAB 2015

  • NUGEN Audio at IBC 2015

    NUGEN Audio at IBC 2015

  • NUGEN Audio at BVE 2015

    NUGEN Audio at BVE 2015

  • Nugen Audio at NAB 2014

    Nugen Audio at NAB 2014

  • NuGen Audio at IBC 2013

    NuGen Audio at IBC 2013

  • The Telos Alliance at IBC 2016

    The Telos Alliance at IBC 2016

  • Wohler at IBC 2016

    Wohler at IBC 2016

  • RTW at IBC 2014

    RTW at IBC 2014

  • RTW at NAB 2014

    RTW at NAB 2014

  • Cobalt Digital at NAB 2014

    Cobalt Digital at NAB 2014

  • TSL Products SAM1 MADI at BVE 2014

    TSL Products SAM1 MADI at BVE 2014

  • RTW at IBC 2013

    RTW at IBC 2013

  • TSL Products at NAB 2013

    TSL Products at NAB 2013

  • TSL Systems at BVE 2013

    TSL Systems at BVE 2013

  • TSL Products at BVE 2013

    TSL Products at BVE 2013

  • RTW at NAB 2012

    RTW at NAB 2012

  • Emotion Systems at NAB 2012

    Emotion Systems at NAB 2012

  • Triveni Digital at NAB 2012

    Triveni Digital at NAB 2012

  • Qualis at NAB 2012

    Qualis at NAB 2012

  • DK-Technologies at NAB 2012

    DK-Technologies at NAB 2012

  • TSL at BVE 2012

    TSL at BVE 2012

  • Sonifex at BVE 2012

    Sonifex at BVE 2012

  • Emotion Systems at BVE 2012

    Emotion Systems at BVE 2012

  • HHB and TC Electronic at BVE North2011

    HHB and TC Electronic at BVE North2011

  • Junger Audio at IBC2011

    Junger Audio at IBC2011

  • Volicon at IBC2011

    Volicon at IBC2011

  • TC Electronic at IBC2011

    TC Electronic at IBC2011

  • Cobalt Digital at IBC2011

    Cobalt Digital at IBC2011

  • RTW at IBC2011

    RTW at IBC2011

  • DK Technology at IBC2011

    DK Technology at IBC2011

  • Linear Acoustic at IBC2011

    Linear Acoustic at IBC2011

  • 7.1.2 Dolby Atmos support by Halo from Nugen Audio at NAB 2017

    7.1.2 Dolby Atmos support by Halo from Nugen Audio at NAB 2017

  • Nugen Audio at IBC 2016

    Nugen Audio at IBC 2016

  • Nugen Audio at NAB 2016

    Nugen Audio at NAB 2016

  • Nugen Audio Halo Upmix at BVE 2016

    Nugen Audio Halo Upmix at BVE 2016

  • Nugen Audio at IBC 2012

    Nugen Audio at IBC 2012

  • Nugen Halo Upmix and AMB Updates at IBC 2017

    Nugen Halo Upmix and AMB Updates at IBC 2017

  • AJA Video HDR Image Analyser 12G for the latest 4K/UltraHD HDR standards at ISE 2020

    AJA Video HDR Image Analyser 12G for the latest 4K/UltraHD HDR standards at ISE 2020

  • Tony Taylor from TMD talks about Post Production

    Tony Taylor from TMD talks about Post Production

  • Connecting the Virtual and KVM World with the ADDER Infinity 3000 at ISE 2020

    Connecting the Virtual and KVM World with the ADDER Infinity 3000 at ISE 2020

  • Davinci Resolve 14 with Fairlight from Blackmagic Design at NAB 2017

    Davinci Resolve 14 with Fairlight from Blackmagic Design at NAB 2017

  • Forscene at IBC 2014

    Forscene at IBC 2014

  • Quantel LiveTouch at IBC 2014

    Quantel LiveTouch at IBC 2014

  • Quantel deal with AFP at IBC 2014

    Quantel deal with AFP at IBC 2014

  • Snell Kahuna Production Switcher at IBC 2014

    Snell Kahuna Production Switcher at IBC 2014

  • Forbidden Technologies FORscene at BVE 2014

    Forbidden Technologies FORscene at BVE 2014

  • Forbidden Technologies FORscene App at BVE 2014

    Forbidden Technologies FORscene App at BVE 2014

  • Tony Taylor from TMD talks about LTFS at IBC 2013

    Tony Taylor from TMD talks about LTFS at IBC 2013

  • Tony Taylor from TMD talks about Mediaflex CI

    Tony Taylor from TMD talks about Mediaflex CI

  • Facilis at IBC 2013

    Facilis at IBC 2013

  • Facilis at NAB 2013

    Facilis at NAB 2013

  • Autodesk at NAB 2012

    Autodesk at NAB 2012

  • SGO at IBC2011

    SGO at IBC2011


Related Shows
  • KitPlusTV summarise the Broadcast and Pro Video News 19th April 2021

    KitPlusTV summarise the Broadcast and Pro Video News 19th April 2021


Articles
Cloud integration: The only way is up
Francois Vaillant

In 2017 we saw the introduction of SMPTE 2110 and since then, the transition to IP has emerged as a priority for broadcasters looking to streamline their operations, decrease their footprint and effectively integrate with an industry in a rapid state of flux. A 2020 survey by Devoncroft found that almost 20% of broadcasters had already deployed SMPTE 2110, and over 25% were planning to do so. Then came the pandemic, precipitating the need for on-the-fly collaboration and accelerating the transition to remote, virtual and cloud production.

Tags: dejero | smpte 2110 | dazzl | streaming | Francois Vaillant
Contributing Author Francois Vaillant Click to read
The Cloud - a measured approach
Ciaran Doran

With the buzz of ‘cloud’ everywhere in our industry it would be natural to think that cloud is the only game in town. Isn’t it time to step back and consider very carefully how, or whether, you make that journey to the cloud?

Tags: cloud | rohde and schwarz | rohde | schwarz | Ciaran Doran
Contributing Author Ciaran Doran Click to read
Meeting the specification
Chris Smeeton

A good technical specification will detail precisely what is required, from the equipment to the cables connecting it. Many specifications will give  particular manufacturers and model numbers. On many occasions, this makes tendering simple and gives vendors a secure and fair way to bid.

Tags: CPR specification | argosy cable | fire safe cable | eu standard cable | chris smeeton | Chris Smeeton
Contributing Author Chris Smeeton Click to read
Avid and Rohde & Schwarz
Ciaran Doran

Rohde & Schwarz is the perfect ingest partner to build flexible workflows with Avid.

Tags: Rohde and Schwarz | avid | spycernode | editing | asset management | venice | Ciaran Doran
Contributing Author Ciaran Doran Click to read
Sennheiser MKE 400 hands on review and test
KitPlus

Sennheiser have just released two products aimed at simplifying audio on the move, the MKE400 shotgun microphone and the XS Lav Mic, in this review we’re looking at the MKE400.

Tags: sennheiser mke400 | sennheiser mke 400 | sennheiser mke 400 quality | best microphones for youtube | mic for youtube videos | sennheiser mke 400 hands on | microphone review | iphone videography | microphones | sound for video | camera microphone | microphone for iphone | microphone for youtube | video microphone | shotgun mics | smartphone microphone | vlogging mic | best microphone for video | shotgun microphone review | mke 400 | sennheiser mke 400 hands on review | sennheiser mke 400 test | KitPlus
Contributing Author KitPlus Click to read