Manual

2.1.1 Dolby AC-4 features
The key aspects of Dolby AC-4 highlight the improvements and expanded user experiences that
the product brings to the broadcast environment. The list provided here does not cover all
aspects of Dolby AC-4. For a complete description, refer to the respective specifications (ETSI TS
103 190-1 for channel-based audio and ETSI TS 103 190-2 for immersive and personalized audio).
Summary of Dolby AC-4 features:
•
Improved compression efficiency
Compared to Dolby Digital and Dolby Digital Plus, Dolby AC-4 provides significantly better
compression efficiency and better audio quality at a fixed bit rate or the same audio quality
at a lower bit rate.
Dolby AC-4 provides the same industry-standard, multichannel 5.1 audio quality as Dolby
Digital Plus at half the data rate, which means multichannel audio can be encoded using 96
kbps.
•
Support for Dolby Atmos content
Provides tools to process the newest generation of object-based audio content.
•
Personalization
Provides tools for users to personalize their listening experience.
•
Built-in, metadata-based multichannel and multiband dynamic range and loudness control
as well as integrated postprocessing
Advanced dynamic range compression is known from Dolby Digital and Dolby Digital Plus.
Dolby AC-4 improves the audio quality further by using multiband and multichannel
compression algorithms compared to the original method, which used a single wideband
gain factor for all channels.
Dolby AC-4 dynamic range control supports the transmission of user-selectable dynamic
compression parametric curves and compression gains for more flexibility and wider
support.
•
Support for the newest generation of consumer playback devices to adapt the content to
specific listening environments and playback scenarios such as:
•
Audio/video receiver and home theater
•
Portable/mobile speakers
•
Portable/mobile headphones
•
Flat-panel TV
•
Advanced dialogue enhancement
Provides a better experience to users with hearing impairments.
•
Built-in audio/video (A/V) frame alignment
Dolby AC-4 supports frame sizes that enable alignment of audio frames with most popular
video frame sizes. This feature can be used to circumvent one of the common sources for A/V
synchronization problems (also referred to as digital turnaround).
•
Excellent audio quality for legacy content configurations
•
Integrated headphone virtualization and support for immersive stereo decoding
•
Speaker virtualized output
•
Immersive (5.1.2) channel-based output
Overview of the Dolby Professional Reference Decoder DP580
Dolby Professional Reference Decoder DP580 v2.0 user's guide
16 January 2018 8