Grass Valley Imagestore 750 v.3.0.1 - Manual (Page 144)

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Advanced Audio
Dolby
 Note: This option is enabled only for Dolby E.
• ‘Surround Mix Level’
This indicates the nominal down-mix level of the surround channels if they are in use.
Choices include the following:
• 0.707 (–3 dB)
• 0.500 (–6 dB)
• 0
 Note: This option is enabled only for Dolby E.
• ‘Dolby Surround Mode’
This indicates whether program has been encoded in Dolby Surround. It can take one of the
following values. Choices include the following:
• Not indicated
• Not encoded
• Encoded
 Note: This option is not used by the Dolby Digital (AC-3) decoder, but may be used by
other portions of the audio reproduction equipment.
• ‘Dialogue Normalization’
The dialogue element of program audio generally serves as a reference for the loudness of
all the other audio. When audio from different sources is reproduced, the apparent loudness
of the dialogue element frequently varies from source to source.
The ‘Dialogue Normalization’ parameter indicates the average dialogue loudness during the
program. It is used by the section of the sound reproduction system responsible for setting
the reproduction level.
• ‘Mix Level’
The mix level indicates the absolute acoustic sound pressure level of an individual program
during the final audio mixing session. The code represents a value in the range 0–31. The
peak mixing level is 80 plus the value of the mix level in dB SPL, or 80 to 111
dB SPL. The peak
mixing level is the acoustic level of a sine wave in a single channel whose peaks reach 100
percent in the PCM representation. The absolute SPL value is typically measured by means of
pink noise with an RMS value of 20 or 30
dB below the peak RMS sine wave level. The value of
the mix level is not typically used within the Dolby Digital (AC-3) decoder, but can be used
by other parts of the audio reproduction equipment.
• ‘Room Type’
The room type indicates the relative size and monitor frequency response curve of the mix-
ing room used for the final audio mixing session. The room type value is not typically used
by the AC-3 decoder, but can be used by other parts of the audio reproduction equipment.
Choices include the following:
• Not indicated.
• Large room.
• Small room.