Dolby Laboratories Multichannel Audio Tool DP570 - Manual (Page 110)

94 Dolby ® DP570 Multichannel Audio Tool User’s Manual
A Guide to Dolby Metadata
Figure D‐3
LFE Channel
The status of the LFE Channel parameter indicates to a Dolby Digital encoder whether an
LFE channel is present within the bitstream. Channel mode determines whether the LFE
Channel parameter can be set. You must have at least three channels to be able to add an
LFE channel.
Bitstream Mode
This parameter describes the audio service contained within the Dolby Digital bitstream.
A complete audio program may consist of a main audio service (a complete mix of all the
program audio), an associated audio service comprising a complete mix, or one main
service combined with an associated service. To form a complete audio program, it may be
(but rarely is) necessary to decode both a main service and an associated service using a
maximum total bit rate of 512 kbps. Refer to the Guide to the Use of the ATSC Digital Television
Standard, Document A/54, for further information. Although a detailed description of each
option follows, in practice, most programming uses the default setting, Complete Main. An
example of an exception to this rule is a special karaoke DVD, or an emergency service
within digital television.
Table D-4 Channel Mode Definition and Data Rates
Channel Mode Setting
Definition and Data
Rate
1+1 Dual mono (not valid for
DTV broadcast or DVD
production)
1/0 Mono From 56 kbps, usually
96 kbps
2/0 Stereo From 96 kbps, usually
192 kbps
3/0 From 256 kbps
2/1 From 256 kbps
3/1 From 320 kbps
2/2 From 320 kbps
3/2 From 384 kbps, often
448 kbps
Table D-5 LFE Channel Settings
LFE Channel Setting
Enabled
Disabled
Table D-6 Bitstream Mode Options
Bitstream Mode
Setting Definition
Complete Main (CM) CM flags the bitstream as the main audio service for the program and
indicates that all elements are present to form a complete audio
program. Currently, this is the most common setting. The CM service
may contain from one (mono) to six (5.1) channels.