Loudness ebu mar 2012 [compatibility mode]

What is Loudness?Navigating the Compliance

Requirements of Loudness Monitoring

BS.1770, EBU PLOUD R128, Tech 3341/2/3

Andrew Sachs

VP. Product Management

Jennifer Knutel

Sr. Dir of Marketing

• Why Loudness?

• What is Loudness

– Specification - BS.1770

– Recommended Practice

Agenda

– Recommended Practice

• EBU PLOUD R128, Tech 3341/2/3

– Regulations and compliance

• Volicon loudness solutions

• Q&A

Why Loudness?

• Analog (FM) sound world of yesterday

• Dynamic range limited:

– Upper end by modulation limits and

adjacent channel

– Lower end by noise floor

Channel

Upper

Modulation

Limit

Noise

Floor

Peak

target

Typical

Program

Range

• Operators leveled programming using peak

meters

• Programs were perceived as similar levels

• Consumers do not feel they have to adjust

the volume

Floor

Peaks leveled

Across Programs

Tolerable

Perceived

Differences

One

Volume

Setting

Why Loudness?

• Digital Sound

• Much greater dynamic range than analog

• Better transmission methodsAnalog

Digital

• Metadata on dynamic range

• Able to create the “theater experience”

+40dB more

dynamic range

Why Loudness?

– Added dynamic range/headroom can be used

differently by different types of content

Use Dynamic Range Make content LOUDERNo Change

Create theater

experience.

Movies, Music

..

Talk or News

programs

People pay more

attention

Advertisers

who want your

attention

Why Loudness?

• Tragedy of the Commons

• Level according to peaks

• Users pay more attention to loud content

– Advertising recognition is higher

– Advertisers KNOW and use this

Difference

is much

larger

than

with analogPGM

Ad

PGM

Ad

PGM

– Advertisers KNOW and use this

• Users feel they need to adjust volume

– Detracting from their overall QoE

– Solution:

• Level according to “loudness perception”

• Content flexibility with good user experience

– Now, what is “loudness perception”?

Volume

Adjustments

No Volume

Adjustments

What is Loudness?

Specification

What is loudness?

Recommended

BS.1770-1/2 LKFS gated

Recommended

Practices

How to use loudness

Regulation

How it is enforced

R128Tech 3341/2/3 A/85 RP TR-B32

What is Loudness? Specification

• Goal of specification: Objectify the Subjective

• Result : ITU Recommendations on Loudness Measurement

– BS.1770-1 (09/2007) - Algorithms for Loudness and true peak

– BS.1770-2 (03/2011) - Added gating – more on this later– BS.1770-2 (03/2011) - Added gating – more on this later

• Not all frequencies are created equal

– K-weighting

– Upper frequencies effect amplified up to 4dB

– Lower frequencies attenuated (~80Hz 3dB)


• Not all channels are created equal

– Left (L), Right (R) and Center (C)

• 1.0 weighting (+0.0 dB)

• Stereo and 5.1 will measure the same

Rs

L

C

R

1.0 (0.0 dB)

– Rear Surrounds are 1.41 weighted (+1.5 dB)

• Sounds from side/back perceived louder

– LFE Channel (.1) not counted

• Low frequency content tends not to affect loudness perception

LFE (.1)

RsLs

1.41

(+1.5dB)1.41

(+1.5dB)

0.0 (- ∞ dB)


• One measurement summed for entire audio track

– Mono, Stereo, 5.1

– Stereo channels will measure the same in 5.1 (same weights)

OR ORL K-WeightMean

Square0 dB

R

C

Ls

Rs

K-Weight

K-Weight

K-Weight

K-Weight

Mean

Square

Mean

Square

Mean

Square

Mean

Square

0 dB

0 dB

+1.5dB

+1.5dB

∑One

LOUDNESS

Value


• How to not count periods of silence or very low levels?

– Counting periods of silence would “lower the loudness level”

– Could be gamed by advertisers – Yell for 10s, silent for 20s

– Gate to only measure relevant audio

• BS.1770-2 added a cascaded relative gate of -10dB GATE• BS.1770-2 added a cascaded relative gate of -10dB

– Do not count periods that are > 10 dB lower (8dB in R128 original)

– Determined every 10Hz with 400ms windows � 75% overlap

Ungated

average

Higher

Gated

average

-10dB gate

--10dB

One loudness value,

AFTER gating

?

gate


• Meausre for the entire length of the content

� Short form -< 2 minutes ad or promo

� Long form - > 2 minutes program or promo

� Overall channel - time (e.g. 6h, 1d, ..)� Overall channel - time (e.g. 6h, 1d, ..)

• Into one LKFS measurement (dB scale)

� Logarithmic K-weighted Full Scale

� FS – 0.0 is Digital Full Scale (max)

� E.g. -10 LKFS is 10x more than -20 LKFS

-x.yz

LKFS


• Lack of international agreement on Gate

• EBU, BS.1770-2, BS.1864 �

– Cascaded, -10dB level based

• ATSC RP A/85 �

– Short form – no gate(yet), measure entire content– Short form – no gate(yet), measure entire content

– Long Form (>2m) – “Anchor Element”

– “Anchor element” suggested to be “Dialog Level”

• Measure just the dialog portion of the content

• Except when not practical (music program)– then measure all content

• Use the same gating your regulator/partner

– Dialog/level, short/long interval, level gate #

What is Loudness ? Recommended Practice

• ATSC RP A/85 July 2011

– Does not incorporate BS-1770-2 (March 2011)

– Specifically, does not include of level gating

– Hints that future versions may change

• ATSC RP A/85 does say:

– Target Level - -24 LKFS

– Utilize DIALNORM properly.

– Short Form (<=2m) measurement – no gating, measure entire asset

– Long Form (>2m) measurement – measure dialog as “anchor element”

-24 LKFS ��


• EBU PLOUD R128 AUG 2011

– Use Loudness, not QPPM to level audio

– Utilize BS.1770 for base measurement

– Loudness Unit (LU) is the relative unit

• : Still Log10 � 1LU== 1dB

Who can

Spot the

“128”?

• : Still Log10 � 1LU== 1dB

– Absolute measures are LUFS not LKFS units

• 0.0 LUFS is the max Full Scale

• LUFS included gating, LKFS did not (at the time)

• Unit labeling highlights BS.1770 differences

• These differences are disappearing

LKFS �� LUFS

no gate gate



– Loudness Range (LRA)

• measures utilized dynamic range

• Allows proper audience

• Enables detection of companding

# Samples

10% 5%

Program Loudness Range

(LRA)

• Enables detection of companding

– (program LRA changes)

– -23 LUFS is target level +/- 1LU

• LUFS units imply gating

• Live programming has greater tolerance

– Loudness metadata (e.g. DIALNORM) shall indicate -23

Loudness

# Samples

-23 LUFS ��

-31

-31

LUFS

-31

-1

-12

-23

Higher Level �

Higher

Attenuation

Set Top Box



– Tech Recommendation 3341 additionally says

• Momentary (400ms) measurement

• Short Term (3s) – measurement

• Integrated (program) measurement

Loudness

Momentary

Short Term

Integrated

• Integrated (program) measurement

– Measure over program duration

• 8 Defined Test Signals to check compliance

– Tech Recommendation 3342 additionally says

• How to measure Loudness Range (LRA)

• 6 defined test signals for Loudness Range

– Tech Recommendation 3343 & 3344 additionally says

• Practical Guidelines – how to do all of this!

timeLoudness

What should you do for complaince?

• Normalize content to -23 LUFS

-23

– Network Feeds – Monitor over long periods. Issue corrective actions with examples content with non-compliance. Networks have same incentives.

-23

-23

-23

compliance. Networks have same incentives.

– Tape based assets – Measure loudness and compensate on mixing.

– File based assets – Measure and correct to -23 LKFS.

– Live Feeds – Target mixing Monitor loudness for large discrepancies. Most leeway given on levels of live content.

What should you NOT do for compliance?

• Do not

– Fix assets levels on the fly - exception being live programming mixing.

– Correct embedded commercials - too late by the time – Correct embedded commercials - too late by the time they are delivered.

– Wait for penalties- Do not wait that is. Utilize monitoring and to take corrective action

Like a factory, ensuring quality inputs and

process control will ensure a quality product.

What is Loudness ? Legislation

• Varies country by country. Some examples

• Italy AGCOM -

– Measure as the customer experiences (post-STB)

– Max 5 day channel I deviation

– Max program to program deviation– Max program to program deviation

• France CSA (Audiovisual Superior Council)

– For short form content, maximum measurements

• Max I = -23, Max S = -20, Max M = -16 LUFS

– Long form programs: 5LU < LRA < 20 LU

– Tolerance varies by program type

• E.g. short form +/-1LU, old programs +2/-3LU

For more information please

contact us ([email protected])

and come see us at

NAB Booth SU5715

+1 781 221 7400

Andrew Sachs

VP. Product Management

[email protected]

Jennifer Knutel

Sr. Dir of Marketing

[email protected]

Loudness ebu mar 2012 [compatibility mode]

Technology

Transcript of Loudness ebu mar 2012 [compatibility mode]