This wall chart highlights the key terms and standards required for the delivery of premium audio across broadcast and multiscreen workflows. It is designed as a quick reference for people who are responsible for delivering rich media experiences acress broadcast and over the top networks

1. Audio Essentials for Broadcast and Multiscreen
The Power of Sound
The Broadcast and Multiscreen Content Delivery Chain
Dolby Audio Metadata
Metadata, carried from end-to-end in the encoded bitstream,
describes the encoded audio and conveys information that
precisely controls downstream encoders and decoders. Metadata
gives content providers control over how original program material
is reproduced in the home taking into account the configuration of
the user’s setup and on the user’s preferences. Key audio
metadata parameters include the following:
“Sound is half the experience.”
– George Lucas
Consumers value sound quality overall…
DOWNMIX - controls stereo/mono downmix (AAC - matrixmixdown)
Q. In your opinion, how important are the following to a quality audio listening
experience?
Sound quality
ProductionContent Creation
88%
Compelling audio content
Distribution
DYNAMIC RANGE CONTROL – Metadata that controls
dynamic range for stereo/mono and ‘late night’ outputs
Playback
85%
Quality audio electronics devices
Dolby E
The ability to listen on
any device you own
Portability
52%
The ability to listen in
any room in your home
MPEG2 TS
HLS
Dolby Digital
MPEG2
MPEG2 4:2:2
MXF
Dolby Digital Plus
MPEG2 4:2:2
MXF
Smooth Streaming
Dolby Digital Plus
H.264
H.264 4:2:0
MOV
Dolby Metadata
H.264 4:2:0
MOV
HDS
Dolby Metadata
H.264 4:2:2
AAC
H.264 4:2:2
MP4
MPEG-DASH
UV CFF
UV CSF
HE-AAC
HE-AAC
56%
MPEG2-LII
MPEG2-LII
Headend
Notions of Quality: Audio Expectations of Consumers – CEA 2011
…and they are not satisfied!
Decode
Post Production
Encode
Decode
Encode
Decode
Contribution
Q. How important is sound or audio quality to you when watching or listening to each of the
following devices?
Q. How would you rate the sound or audio quality in each of the following devices?
Encode
Statistical Multiplex
Live
Broadcast
58%
31%
Very Important
Very Satisfied
36%
Media Tablet
20%
Transcode
45%
Laptop
computers
Live
Content
25%
Adaptive Streaming
Protocol Comparison
Proprietary
Yes
Yes
MP4
Proprietary
Yes
Yes
MPEG-TS
Proprietary
Yes
Yes
MP4, FLV
Yes
Standard
Yes
Yes
MPEG2-TS
or MP4
Yes
Yes
No
No
Yes
No
xBox,
Windows 8,
iPhone OS
3.09,
connected
TVs
iPad,
iPhone OS
3.0, devices
running
QuickTime
X, Android
4.1 and
above
Flash
Player 10,
AIR,
Chrome and
Internet
Explorer
Browsers
Flash
Player 10,
AIR, set top
boxes,
connected
TVs
Yes
Asset
Distribution
Live Transcode
IP
ABR Packaging
ABR Packaging
ABR Packaging
File-Based Transcode
Un-managed
CDN
ABR Packaging
File-Based Transcode
File Fetch
Managed CDN
Origin
Server
File-Based Transcode
ABR Packaging
Multi-bitrate files
Audio Codecs
Codec
Standard
Dolby E
Dolby Digital
Dolby Digital Plus
PCM
MPEG-2 Audio
Layer II
MPEG4 AAC-LC
HE-AAC
HE-AAC v2
AC-3 as described in
ETSI TS 102 366
EAC-3 as described
in ETSI TS 102 366
AES3-2003
AES5-2003
IEC 60908 Ed. 2.0
ISO/IEC 11172-3,
ISO/IEC 13818-3
ISO/IEC 144963:2001 Amd 1:2003
ISO/IEC 144963:2005 Amd 2:2006
Surround Sound Pass-Through
Allows Mobile device to connect
through HDMI to home theatres
ABR Packaging
Live Transcode
Live Transcode
Decode
TS for Dynamic Packaging Origin Servers
MPEGAdobe
Apple
Dynamic
Microsoft
HTTP
HTTP Live
Adaptive
Smooth
Dynamic
Streaming Streaming
Streaming
Streaming
(HLS)
Over HTTP
(HDS)
(DASH)
Yes
Yes
Yes
Yes
Audio Regulation
Eliminates distortion caused by
overdriving built-in speakers
Volume Optimization
Matches playback to built-in
speakers frequency response
Multi-bitrate streams
NLE
Offline
Content
Dialog Enhancement
Enhances dialog volume so
that it can be heard over
background sounds.
VOD
Store
broadcast
multi-screen
Studios
Transcode
Surround Sound Virtualization
Creates a virtual surround sound
experience over headphones or builtin speakers
Cable
Capture
IP
Multiple Audio
Channels
Supports
multiple DRMs
Device Support
Metadata Editing
Telco
ADI Packaging
NLE
22%
Source: 2011 Dolby Global Brand Tracker
Dolby Digital
Plus Support
Specification
VoD Support
Live Support
Media Container
File-Based Transcode
41%
Smartphones
Feature
Catch
Playout
Dolby Mobile Device
Post Processing
Volume Leveling
Provides a consistent device
volume across all content
Capture
Mobile
Production
CHANNEL CONFIGURATION - signals channel configuration
DTH
Broadcast
Portable digital
media players
DIALNORM – Dialogue normalization metadata that represents
program loudness (AAC program reference level)
AAC
55%
Listening environment
MPEG2 4:2:0
WAV
57%
Dolby Digital
PCM
68%
MPEG2 TS
Dolby Metadata
72%
Access to any audio
content you want
MPEG2 4:2:0
Applications
Dolby E is a professional audio format designed to carry up to 8
channels of audio, metadata and timecode on stereo PCM
interfaces.
Theatrical movie presentation, Digital TV service & home-video
(personal recorders, DVD, etc.)
Dolby Digital Plus has the same fundamental bitstream structure
and transform length as Dolby Digital with additional benefits,
such as audio description and 7.1 channels.
PCM is standard form of uncompressed digital audio sometimes
used for lossless primary distribution and compact disc digital
audio system.
DAB, DVB, DVD
Digital TV service, Internet streaming
HE-AAC is a lossy data compression scheme for digital audio. It
is an extension of AAC LC optimized for low-bitrate applications
such as streaming audio.
HE-AAC v2 is a standardized and improved version of the HEAAC codec.
Loudness Fundamentals
Standards
Publications and
Working Practices
Dolby Seamless Bit Rate and
Channel Configuration Switching
Loudness
Measurement
Techniques
Loudness
Regulations
Key Terms
Description
ITU-R BS.1770 -, Algorithms to Measure Audio Programme
Loudness and True-Peak Audio Level
EBU R 128 - Loudness Normalization and Permitted Maximum Level
of Audio Signals
ATSC A/85 - Techniques for Establishing and Maintaining Audio
Loudness for Digital Television
ITU-R BS.1864 - Operational practices for loudness in the
international exchange of digital television programmes
A-Weighting – A measurement technique that applies a set of equal
loudness contours to measured loudness levels to account for the
relative loudness perceived by the human ear
K-Weighting – A measurement technique that applies both loudness
contours and gating to measure loudness levels.
CALM Act – The ‘‘Commercial Advertisement Loudness Mitigation
Act’’ is a US law passed to regulate the volume of audio in ads.
DialNorm - The loudness metadata parameter that Indicates the
average weighted level of the dialogue within a program
DRC – Dynamic Range Control is the metadata parameter that limits
the extremes of an audio signal and allows the viewer to select mode
depending on equipment: Line Mode (Midnight mode) or RF Mode.
Dolby Dialogue Intelligence™- Dialogue Intelligence™ allows
users to quantify the level of dialogue automatically from the input
signal, by recognizing and measuring loudness only during the
presence of speech.
Anchor Element - The perceptual loudness reference point or
element around which other elements are balanced in producing the
final mix of the content. Typically chosen to be program dialog.
Dialogue Level - The loudness, in LKFS units, of the Anchor
Element.
Gating - A gating scheme pauses loudness measurement when the
audio level drops below a given threshold relative to an ungated
measurement of the same program material.
LKFS - Loudness, K-weighted, relative to Full-Scale is the loudness
measurement unit commonly used in the US.
LUFS – Loudness Unit relative to Full-Scale is the loudness
measurement unit commonly used in EBU applications.
Measurement Timescale - Measurements are made on four
timescales: Momentary (0.4s); Short-term 3s ; Short-term (10s –
historical value) and Integrated (whole program duration)
Target Levels – A specified value for the Anchor Element (Dialog
Level) established to facilitate content exchange from a supplier to
operator. ATSC A/85 recommends a target of -24 LKFS +/- 2. The
EBU R 128 sets the target level at -23 +/- 1LUFS.
True Peak – The maximum absolute level of the signal, measured
per ITU-R BS.1770. Allows the accurate indication of the headroom
between the peak level of a digital audio signal and the clipping level