Dolby Laboratories DP570 - Manual (Page 103)

A Guide to Dolby Metadata Downmixing
Dolby ® DP570 Multichannel Audio Tool User’s Manual 91
As with stereo mixing where the mix is monitored in mono on occasion to maintain
compatibility, multichannel audio mixing requires the engineer to reference the mix to
fewer speaker channels to ensure compatibility in downmixing situations. In this way,
Dolby Digital, using the metadata parameters that control downmixing, is an “equal
opportunity technology,” in that every consumer who receives the Dolby Digital data
stream can enjoy the best audio reproduction possible, regardless of the playback system.
It is important to consider the output signals from each piece of equipment that can receive
a Dolby Digital program in the home. Table D‐2 shows the output types from different
equipment.
Set‐top boxes, used to receive terrestrial, cable, or satellite digital television, typically offer
an analog mono signal modulated on the RF/Antenna output, a line‐level analog stereo
signal, and an optical or coaxial digital output. DVD players offer an analog stereo and a
digital output, and some offer a six‐channel analog output (for a 5.1‐channel presentation).
Portable DVD players offer analog stereo, headphone, and digital outputs. DVD players in
computers and game consoles offer a digital output as well as analog stereo, headphone,
and possibly six‐channel analog outputs. 5.1‐channel amplifiers, decoders, and receivers
have six‐channel analog outputs and possibly six speaker‐level outputs.
In all of these cases, a Dolby Digital decoder creates the analog audio output signal.
In the case of the set‐top box or DVD player, the analog stereo output is a downmixed
version of the Dolby Digital data stream. The digital output delivers the Dolby Digital data
Table D-2 Outputs from Different Equipment Types
Equipment
Output
Digital
5.1-Channel
Analog
Two-Channel
Analog
RF
Remodulated
5.1‐channel amplifier
The standard home
theater A/V amp
r r
5.1‐channel decoder r r
High‐end DVD player r r r
DVD player r r
PC
Includes games consoles
r (some units) r
High‐end set‐top box
Often HDTV
r r r r
Set‐top box
Usually SDTV
r r r
IDTV
TV set with an integrated
digital TV tuner
r r
High‐end TV
Large screen TV with a
5.1‐channel speaker
system
r r