Audio Formats - ZyXEL Communications DMA-1100P User Manual

Table 16 OPTION > Audio Output Settings (continued)
LABEL
Dolby Digital
WMA
Auto Volume
Control Strength
OK
CANCEL

10.8.1 Audio Formats

This section provides background information on audio formats mentioned in the previous
section.
10.8.1.1 S/PDIF
S/PDIF (Sony/Philips Digital Interface Format) is also IEC 958 type II, part of IEC-60958. S/
PDIF is a collection of low-level protocol and hardware specifications for carrying digital
audio signals between devices and stereo equipment.
10.8.1.2 AAC
AAC (Advanced Audio Coding) is a standardized digital audio compression method. Sony,
AT&T, Dolby, Nokia, Fraunhofer (FhG) and other companies cooperated to develop AAC to
provide improved performance compared to MP3 (MPEG-1 Audio Layer 3). Various products
including Apple's iTunes and iPod, the Sony PlayStation 3 and many cell phones support
AAC playback. AAC has been promoted as the successor to MP3 although at the time of
writing, MP3 still remains popular. AAC is also known as MPEG-4 AAC because it is
included in the Moving Pictures Experts Group (MPEG) MPEG-4 standard.
10.8.1.3 Dolby Digital
Dolby Digital is one of several audio compression technologies (codecs) produced by Dolby
Laboratories.
Dolby Digital (also called AC-3) is the most common version. It contains up to six discrete
channels of sound. Five channels for normal-range speakers (right front, center, left front,
right rear and left rear) and one channel for the subwoofer. This is often abbreviated as 5.1.
The Dolby Digital format also supports mono and stereo usage.
DMA-1100P User's Guide
DESCRIPTION
Select whether or not the DMA sends digital audio output through the S/PDIF audio
connector for Dolby Digital music files.
Select LPCM to turn on the channel digital output (also called left and right or
stereo) for Dolby Digital music files.
Select OFF to turn off the digital output for Dolby Digital music files.
Select whether or not the DMA sends digital audio output through the S/PDIF audio
connector for WMA music files.
Select LPCM to turn on the channel digital output (also called left and right or
stereo) for WMA music files.
Select OFF to turn off the digital output for WMA music files.
Automatic volume control averages the volume during music playback to help
smooth out the sound level. Select the amount of volume smoothing you want for
music playback.
None provides no volume smoothing.
Small provides a low degree of volume smoothing.
Moderate provides some volume smoothing.
Strong provides the greatest degree of volume smoothing.
Select this to save your changes back to the DMA.
Select this to exit this screen without saving your changes.
Chapter 10 Configuring the DMA
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