AN AFTERNOON ON LOUDNESS Las Vegas Convention Center, room S204 1 PM - - PowerPoint PPT Presentation
Tuesday 17 April AN AFTERNOON ON LOUDNESS Las Vegas Convention Center, room S204 1 PM Thomas Lund, Dev. Manager HD, TC Electronic: Program Delivery in Accordance with ITU-R BS.1770-2 2 PM Jay Yeary, Director of Audio & Studio Eng., Turner
AN AFTERNOON ON LOUDNESS
Tuesday 17 April
Las Vegas Convention Center, room S204
1 PM Thomas Lund, Dev. Manager HD, TC Electronic:
Program Delivery in Accordance with ITU-R BS.1770-2
2 PM Jay Yeary, Director of Audio & Studio Eng., Turner Studios:
Loudness at Turner Studios and Broadcast Engineering
3 PM Florian Camerer, Chairman of EBU P/LOUD:
EBU R128 Explained and Implemented
4 PM Roundtable and Refreshments, All Presenters, Q&A:
The Welcome Revolution
Program Delivery
In Accordance With BS.1770-2
T h o m a s L u n d
T C E l e c t ro n i c A / S D e n m a r k
NAB After noon on Loudness • Las Vegas • April 17, 2012
Production
Agenda
Transmission Worldview The Standards
ATSC A/85, TR-B32, OP-59, EBU R128 BS.1770-1 and BS.1770-2 Distribution, Cross-platform, Commercials, Metadata From BS.1770 to BS.1770-2 Loudness, True-peak, Gating Guidelines, EBU R128 Tools Loudness Meter Harmonization
Loudness
Leq Weighting
“K”
BS.1770 Loudness
Left
Pre Filter Mean Square RLB Filter
Center L Srnd R Srnd LFE
Currently not used in Loudness Calculations 0.0 dB Pre Filter RLB Filter 0.0 dB Pre Filter RLB Filter 0.0 dB Pre Filter RLB Filter +1.5 dB Pre Filter RLB Filter +1.5 dB Mean Square Mean Square Mean Square Mean Square
Power Gain Sum
Works for mono, stereo and 5.1. Digital input preferable
Words: LUFS, LKFS and LU
LUFS = LKFS
Unit for relative loudness level Compare with [dB] for peak level Loudness at Target Level = 0 LU
LU
Unit for absolute loudness level Compare with [dBFS] for peak level
Only the spelling is different
LUFS and LU
0 LU denotes Target Level.
In this example, Target Level is -23 LUFS.
Remember: LUFS is the same as LKFS.
Meter Examples: LUFS and LU
Program Loudness
Use to normalize programs
A static gain of +5 dB brings Program Loudness Speech and all that Jazz
jumps between programs and commercials.
Four Programs:
Speech normalized example
LUFS
= Too simplistic Broadcast is not Film (speech) Broadcast is not Music (peak)
News Speaker (NLR)
LUFS Green: Ungated Red: Gated
Episode of Friends (MLR)
Green: Ungated Red: Gated LUFS
The Matrix Movie (WLR)
Green: Ungated Red: Gated LUFS
Measurement Gate
EBU NHK & ARIB CRC
Independent verification by NAB/ARIB and by NHK support relative gating method and a threshold of -8 LU. A relative gate between -10 and -6 LU gave significantly better normalization results than no gate, or other gating schemes. Independent verification: -8 LU relative gate shows best MSD performance.
CRC
Leq(K) “Loudness”
Includes silence Focus on foreground Application critical Application friendly Cross-genre critical Cross-genre friendly S i m i l a r n u m b e r s w i t h N L R m a t e r i a l D i f f e r e n t n u m b e r s w i t h W L R m a t e r i a l
Un-gated
ATSC A/85
Gated @ -10 LU
BS.1770-2, R128, TR-B32
True-peak Level
Even in a linear audio system, analog and digital level is not the same.
1 2
AES 23 Nielsen & Lund, 2003
Analog Level: Black Line Digital Level: Red Dots
True-peak Level
Even in a linear audio system, analog and digital level is not the same.
1 2
Analog Level: Black Line Digital Level: Red Dots True-peak Level: Grey Lines
AES 23 Nielsen & Lund, 2003
Original CD level Bit cloned No gain change No sample rate conversion
Note: Meter must be digital & synchronous in order to display true-peak level correctly
CD True-peak Level
Listening example: Don’t Stop, Anastacia Original CD, normal stereo
Remember how loud this track is in order to compare against distortion level in the next examples.
0 dBFS+
Same song, NAD512 CD player, listening here
0 dBFS+
Data Reduction
AES 23, 2003
1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 2 1 2 1 1
Data Bandwidth 50% growth p.a. = double in 20 months
Production
Agenda
Transmission
Distribution, Cross-platform, Commercials, Metadata
The Standards
From BS.1770 to BS.1770-2 Loudness, True-peak, Gating Guidelines, EBU R128 Tools Loudness Meter Harmonization
Worldview
ATSC A/85, TR-B32, OP-59, EBU R128 BS.1770-1 and BS.1770-2
production ingest transmission logging
THE BS.1770
Loudness on three time-scales
Program Loudness Momentary Loudness Short-term Loudness
Program Loudness
The loudness of a full program. Gated measure. Same as BS.1770-2. The loudness variations of a program. Independent of absolute level. 3 sec measure of loudness. Un-gated sliding window. 400 ms measure of loudness. Un-gated rectangular window.
Loudness Range Momentary Loudness Short-term Loudness
I M S
LRA
Harmonized Metering
Loudness Range
Example: LRA = 10 LU
To keep a constant loudness during the program, a +- 5 dB fader gain ride would be required.
Fader ride
Loudness Range
Example: LRA = 10 LU
To keep a constant loudness during the program, a +- 5 dB fader gain ride would be required.
Fader ride
Loudness Range
Example: LRA = 10 LU
To keep a constant loudness during the program, a +- 5 dB fader gain ride would be required.
Delivery Specs
Guideline: Settle expectations. Not car radio, not cinema.
Loudness Range in Production
A set of requirements for loudness meters
How loudness is measured, BS.1770 What numbers are displayed Not the design of meters
EBU Mode Features
=> different meters, same numbers
Momentary Loudness
400 ms, “M”
Short-term Loudness
3 sec, “S”
Target Level
At 12 o’clock and at bold circle
Loudness Range
Variation of program, “LRA”
Program Loudness
Loudness of program, “I”
Target Level
EBU Meter Example
6 L U
Loudness meters easier to use than peak or VU Look at a Sliding measure and Program Loudness Start 1 LU below the Target Tolerance allowed Peak meters are used only to avoid overload Move up to the Target at the end
Live Metering
Live Sports
Sliding Window and Program Loudness
Loudness Range Speech
Get expectations cleared early
Note: Also useful for speech only programs
Production Guidelines
Music True-peak Level
Regular speech: -27 to -23 LUFS Foreground: -24 to -21 LUFS No higher than -1 dBTP
May need further lowering downstream, depending on platform and codec
coming up: Mixing example using BS.1770-2 normalization
BBC Jingle
Ruby Baby, Donald Fagen
Rock’n Roll Train, AC/DC
Monty Croc Olympics
Monty Croc Olympics (same) BBC Jingle (same)
Production Summary
Consider mixing at a calibrated listening level
Production
Agenda
Transmission The Standards
Guidelines, EBU R128 Tools Loudness Meter Harmonization Distribution, Cross-platform, Commercials, Metadata From BS.1770 to BS.1770-2 Loudness, True-peak, Gating
Worldview
ATSC A/85, TR-B32, OP-59, EBU R128 BS.1770-1 and BS.1770-2
2003 “Comfort Zone” paper
Loudness Jumps
How much can be tolerated between programs?
AES 2009 paper: New study based on BS.1770
Loudness Jump Tolerance
Tests with mostly speech Tests with mostly music and effects
50% would adjust volume for a loudness increase of 3 LU for a loudness decrease of 6 LU 95% would adjust volume for a loudness increase of 5 LU for a loudness decrease of 8 LU
Results
Loudness Jump Tolerance
Any type of sound could trigger a level-adjustment.
Conclusion
At the station or using metadata? EBU recommends normalization at the station:
Normalization => Less transmission processing iTunes example
Where to Normalize
Compatibility Delivery Specs
Loudness Range predicts if a program fits consumer requirements,
Guideline: Settle expectations. Not FM radio, not cinema.
Quality Control
To check downstream signal-path incl. satellite, cable and STB.
Loudness Range in Transmission
Loudness Range
The ideal loudness range depends on the listener. A high background noise calls for a low loudness range.
< 6 L U
Target Loudness Range
< 1 2 L U < 2 L U < 8 L U
Apple Sound Check aims at -16.5 LUFS using BS.1770-2
LRA TP G8 no G MaxProgram Loudness at -24 LUFS is too low for pod/mobile platforms
Broadcast Pop, Rock, Clas. Music
Platform Trickle-down: Mobile Platforms
+18 +12 +6HD Production Mobile Platforms
Loudness LUMobile Platforms
Getting the best out of AC3
Normalize Metadata Limit
Normalize programs at the station using BS.1770-2 Change metadata only when switching between stereo and 5.1 Enter -23/-24 as dialnorm number
Note: The AC3 decoder is not speech based. Dialnorm just tells the average level of a program
Protect AC3 from peak overload, especially when transmitting 5.1 format
Production
Agenda
Transmission The Standards
Distribution, Cross-platform, Commercials, Metadata From BS.1770 to BS.1770-2 Loudness, True-peak, Gating Guidelines, EBU R128 Tools Loudness Meter Harmonization
Worldview
ATSC A/85, TR-B32, OP-59, EBU R128 BS.1770-1 and BS.1770-2
Headroom
For WLR content, BS.1770-2 provides 3-4 dB more headroom than BS.1770-1
Bolero, Matrix, Pirates etc.
For movies, BS.1770-2 provides 2-10 dB more headroom than Dolby speech gating
Use to normalize programs at the station to
BS.1770-2
=> more headroom than we have ever had in broadcast!
LUFS
HDTV Only Focus Anchor for WLR
A/85 R128
All Platforms One Number
Monitoring guidelines AC3 manual Distribution guidelines Open standards Harmonized metering Tools to control commercials
Common understanding: Loudness instead of Peak level
Where is ATSC on Loudness?
One commercial Two results
Target
The relative gate enables the measure to focus on foreground sound: Louder and potentially annoying parts of a program.
BS.1770-1 BS.1770-2
Hot Commercials
2nd line of defense: Max Short-term
Max Short-term (S) prevents programs from ever getting
Max Target
Transparency when normalizing commercials is a must
Transparent rules
Better at controlling commercials Better at normalizing WLR content Better at setting metadata than a speech or a peak based measure Open standard, no proprietary technology Automated handling, runs on a server Harmonized metering across brands => cheaper Enables transparent normalization across all platforms
BS.1770-2
International Status Feb 2012
UK, France, Norway, Italy, Israel already started. Germany, Austria, Switzerland: August, 2012 Rest of Scandinavia, Poland, Netherlands: During 2012
CALM Act will be enforced from Dec, 2012. Commercials: (Presumably) old BS.1770 with no gate. Programs: Speech level.
Already using BS.1770-2, LRA, M and S measures
BS.1770-2 starting now, incl. M and S measures
The War Is Over
Hello group! The radio loudness war in Norway is over! I'm happy to inform you that the DAB and DAB+ platforms in Norway as of today are loudness normalized! In a meeting at Lillehammer yesterday all Norwegian DAB/DAB+ content providers agreed to call off the loudness war and back down to a common target level. We are not at -23 LUFS yet, instead we chose -15 LUFS as a preliminary target level. The main reason for this choice is to match the levels between DAB/FM/WiFi in multiplatform receivers. The plan is to shut down FM in Norway in 2017. Then we can lower the target level to -23 LUFS, if not before. Please drop me an email if you want more information. Regards, Bjørn Aarseth _____________________________ Norwegian Broadcasting Corp. www.nrk.no Technology Department R&D Bjørn Aarseth, Senior Engineer Ugly CD Examples
PROGRAM LOUDNESSDon’t let the same happen to broadcast
References
Zwicker & Fastl, 1990 Psychoacoustics - Facts and Models Moore et al., 2003 (JAES no 12) Why are Commercials so Loud? Nielsen & Lund, 1999 - 2006 (AES 23, 107, 109, 111, 121) 0 dBFS+ Level in Mastering and Audio Production Skovenborg & Lund, 2007 - 2009 (AES 123, 125, 127) Loudness Descriptors to Characterize Programs and Music Tracks ITU-R BS.1770-2, ATSC A/85, TR-B32, EBU R128, Tech docs 3341-44 Glossary: www.tcelectronic.com/loudness IRT NoTube project: www.notube.tv AES 132Read More End
Budapest Convention, April 27 Loudness Range - Design and Evaluation Thomas Lund, thomasl@tcelectronic.com