COMPRESSED AUDIO FILES (MP3/
WMA/AAC)
Explanation of terms
.MP3 — MP3 is short for Moving Pictures
Experts Group Audio Layer 3. MP3 is the
most well-known compressed digital audio
file format. This format allows for near “CD
quality” sound, but at a fraction of the size of
normal audio files. MP3 conversion of an
audio track can reduce the file size by
approximately a 10:1 ratio (Sampling: 44.1
kHz, Bit rate: 128 kbps) with virtually no
perceptible loss in quality. The compression
reduces certain parts of sound that seem
inaudible to most people.
. WMA — Windows Media Audio (WMA) is a
compressed audio format created by Micro-
soft as an alternative to MP3. The WMA
codec offers greater file compression than
the MP3 codec, enabling storage of more
digital audio tracks in the same amount of
space when compared to MP3s at the same
level of quality.
. Bit rate — Bit rate denotes the number of bits
per second used by a digital music file. The
size and quality of a compressed digital
audio file is determined by the bit rate used
when encoding the file. .
Sampling frequency — Sampling frequency
is the rate at which the samples of a signal
are converted from analog to digital (A/D
conversion) per second.
. Multisession — Multisession is one of the
methods for writing data to media. Writing
data once to the media is called a single
session, and writing more than once is called
a multisession.
. ID3/WMA tag — The ID3/WMA tag is the
part of the encoded MP3 or WMA file that
contains information about the digital music
file such as song title, artist, album title,
encoding bit rate, track time duration, etc.
ID3 tag information is displayed on the
Album/Artist/Track title line on the display.
. AAC — Advanced Audio Coding (AAC) is a
compressed audio format. AAC offers great-
er file compression than MP3 and enables
music file creation and storage at the same
quality as MP3.
Playback order
.The folder names of folders not containing
compressed audio files are not shown on the
display.
. The playback order is the order in which the
files were written by the writing software, so
3. Audio system
3-7
COMPACT DISC (CD) PLAYER
SymptomPossible cause Possible solution
Music cannot be played back. The disc is inserted upside down. Insert a CD with the label side facing up.
Moisture condensation occurs inside the unit. Wait until the moisture evaporates (approximately 1 hour).
The cabin temperature is too high. Wait until the cabin temperature becomes moderate.
The disc is scratched or dirty. A disc is not always
playable if it is scratched. Wipe off any dirt from the disc.
Depending on the condition in which they are stored,
discs may become unreadable due to deterioration
(for example, keeping the discs in the passenger
compartment, etc.) . Change the disc with a deterioration-free disc. Do
not use a deteriorated disc. The label surface of the
disc may crack or chip, and the layer of the label
surface may eventually peel off.
The compressed audio files cannot be played back. If both music CD files (CD-DA data) and com- pressed audio files (MP3 data, etc.) are mixed on one
disc, the audio compression files cannot be played
back.Prepare a disc that includes compressed audio files
only.
The files are not named using characters that are
compliant with the specifications. Use the character codes and the number of
characters that are compliant with the specifications
for folder names and file names. In addition, always
use “.MP3”, “.WMA”, “.mp3” or “.wma” for file
extensions.
It takes a long time before the music starts playing. The disc contains a large amount of data. Some time may be required to check the files. It is
recommended that unnecessary folders or any files
other than compressed audio files should not be
recorded in a disc.
The sound quality is poor. The disc is dirty.Wipe off any dirt from the disc.
8. Troubleshooting guide
8-7
