Mercedes-Benz HERMES 2.0, Operating Instructions Manual

Page: 75 / 106

Notes on MP3 mode
General notes
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Depending on the volume and format of
the MP3 data, the length of time required
for reading the data may increase.
Permissible data carriers
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CD-R and CD-RW
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USB storage device
Permissible file systems
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ISO 9660/Joliet standard for CDs
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FAT16 or FAT32 for USB storage media
Multisession CDs
For multisession CDs, the content of the first
session determines how Audio 20 will proc-
ess the CD. Audio 20 plays only one session
and gives priority to the audio CD session.
If possible, use Audio 20 to play only CDs that
have been written in one session.
File structure of a data carrier
When you create a disc with compressed
music files, the tracks can be organized in
folders. A folder may also contain subfolders.
A disc can contain a maximum of 255 folders.
Each folder can contain a maximum of
255 tracks and 255 subfolders. A maximum
of 512 files are permitted on an MP3 CD.
The disc may contain no more than eight
directory levels. Files beyond the eighth level
will not be recognized by the system.
Track and file names
Audio 20 does not support ID3 tags. Music
files can contain meta information such as
artist, album or track names. Audio 20 dis-
plays this information during playback.
When you create a disc with compressed
music files, you can assign names to the
tracks and folders. Audio 20 displays these
names if no meta information is available.
If MP3 or WMA files are stored in the root
directory itself, the root directory will also be
treated as a folder. Audio 20 will then show
the name of the root directory as the folder
name.
You must observe the following when assign-
ing track names:
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track names must have at least one char-
acter.
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track names must have the extension
"mp3" or "wma".
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there must be a dot between the track
name and the extension.
Example of a correct track name:
"Track1.mp3".
Permissible formats
Audio 20 supports the following formats:
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MPEG1 Audio Layer 3 (MP3)
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Microsoft Windows Media Audio V2, V7, V8
and V9 (WMA)
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music files in AAC format with the aac and
m4a extension, but not copy-protected
iTunes music files with the extension m4p.
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If a disc contains other files in addition to
music files, the loading time is longer.
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The MP3 audio encoding method is under
license from Fraunhofer IIS (Institut Integ-
rierte Schaltungen – Institute for Integrated
Circuits) and Thomson.
Permissible bit and sampling rates
Audio 20 supports the following types of
MP3 files:
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fixed and variable bit rates from 32 kbit/s
to 320 kbit/s
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sampling rates of 8 kHz to 48 kHz
Audio CD and MP3 mode
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Aud
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