Dolby Laboratories Multichannel Audio Tool DP570 - Manual (Page 111)

Parameter Definitions
Dolby ® DP570 Multichannel Audio Tool User’s Manual 95
Line Mode Compression Profile and RF Mode Compression Profile
For details of the available profiles, see Section D.4 .
RF Overmodulation Protection
This parameter is designed to protect against overmodulation when a decoded Dolby
Digital bitstream is RF modulated. When enabled, the Dolby Digital encoder includes
pre‐emphasis in its calculations for RF Mode compression. The parameter has no effect
when decoding using Line mode compression. Except in rare cases, this parameter should
be disabled.
Main M&E (ME) The bitstream is the main audio service for the program, minus a
dialogue channel. The dialogue channel, if any, is intended to be
carried by an associated dialogue service. Different dialogue services
can be associated with a single ME service to support multiple
languages.
Assc. Visual Imp. (VI) This is typically a single‐channel program intended to provide a
narrative description of the picture content to be decoded along with
the main audio service. The VI service may also be a complete mix of
all program channels, comprising up to six channels.
Assc. Hear Imp. (HI) This is typically a single‐channel program intended to convey audio
that has been processed for increased intelligibility and decoded
along with the main audio service. The HI service may also be a
complete mix of all program channels, comprising up to six channels.
Assc. Dialogue (D) This is typically a single‐channel program intended to provide a
dialogue channel for an ME service. If the ME service contains more
than two channels, the D service is limited to only one channel; if the
ME service is two channels, the D service can be a stereo pair. The
appropriate channels of each service are mixed together (requires
special decoders).
Assc. Commentary (C) This is typically a single‐channel program intended to convey
additional commentary that can be optionally decoded along with
the main audio service. This service differs from a dialogue service
because it contains an optional, rather than a required, dialogue
channel. The C service may also be a complete mix of all program
channels, comprising up to six channels.
Assc. Emergency (E) This is a single‐channel service that is given priority in reproduction.
When the E service appears in the bitstream, it is given priority in the
decoder and the main service is muted.
Assc. Voice Over (VO) This is a single‐channel service intended to be decoded and mixed to
the Center channel (requires special decoders).
Main Sv Karaoke (K) The bitstream is a special service for karaoke playback. In this case,
the Left and Right channels contain music, the Center channel has a
guide melody, and the Left Surround and Right Surround channels
carry optional backing vocals.
Table D-7 RF Overmodulation Protection Settings
RF Overmodulation
Protection Setting
Enabled
Disabled
Table D-6 Bitstream Mode Options (continued)
Bitstream Mode
Setting Definition