Dolby Laboratories DP564 - Manual (Page 85)

DP564 Multichannel Audio Decoder Appendix A: Metadata
A-15
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.
RF Overmodulation Protection
Setting
Enable
Disable
Center Downmix Level
When the encoded audio has three front channels (L, C, R), but the consumer has
only left and right front speakers, this parameter indicates the nominal downmix level
for the center channel with respect to the left and right channels. Dolby Digital
decoders use this parameter during downmixing in Lo/Ro mode when Extended BSI
parameters are not active.
Center Downmix Level
Setting
Definition
0.707 (–3 dB) default The center channel is attenuated 3 dB and
sent to the left and right channels.
0.596 (–4.5 dB) The center channel is attenuated 4.5 dB and
sent to the left and right channels.
0.500 (–6 dB) The center channel is attenuated 6 dB and
sent to the left and right channels.
Surround Downmix Level
When the encoded audio has one or more surround channels but the consumer does
not have surround speakers, this parameter indicates the nominal downmix level for
the surround channel(s) with respect to the left and right front channels. Dolby Digital
decoders use this parameter during downmixing in Lo/Ro mode when Extended BSI
parameters are not active.