compression ratio Lexus GX470 2008 Navigation Manual

AUDIO/VIDEO SYSTEM
264
MP3/WMA files
DMP3 (MPEG Audio Layer 3) and WMA
(Windows Media Audio) are audio
compression standards.
DThe MP3/WMA player can play MP3
and WMA files on CD−ROM, CD −R
and CD −RW discs.
The unit can play disc recordings com-
patible with ISO 9660 level 1 and level
2 and with the Romeo and Joliet file
system.
DWhen naming an MP3 or WMA file, add
the appropriate file extension (.mp3 or
.wma).
DThe MP3/WMA player plays back files
with .mp3 or .wma file extensions as
MP3 or WMA files. To prevent noise
and playback errors, use the appropri-
ate file extensions.
DThe player can play only the first ses-
sion using multi −session compatible
CDs.
DMP3 files are compatible with the ID3
Tag Ver. 1.0, Ver. 1.1, Ver. 2.2 (front au-
dio system only), and Ver. 2.3 formats.
The unit cannot display disc title, track
title and artist name in other formats.
DWMA files can contain a WMA tag that
is used in the same way as an ID3 tag.
WMA tags carry information such as
track title, artist name.
DThe emphasis function is available
only when playing MP3/WMA files re-
corded at 32, 44.1 and 48 kHz. (The
system can play MP3 files with sam-
pling frequencies of 16, 22.05, and 24
kHz. However, the emphasis function
is not available for files recorded at
these frequencies.)
DThe sound quality of MP3/WMA files
generally improves with higher bit rate-
s. In order to achieve a reasonable lev-
el of sound quality, discs recorded with
a bit rate of at least 128 kbps are rec-
ommended.
Playable bit rates
MP3 files:
MPEG1 LAYER3—64 to 320 kbps
MPEG2 LSF LAYER3—64 to 160 kbps
WMA files:
Ver. 7, 8 CBR—48 to 192 kbps
Ver. 9 CBR—48 to 320 kbps
DThe MP3/WMA player does not play
back MP3/WMA files from discs re-
corder using packet write data transfer
(UDF format). Discs should be re-
corded using “pre −mastering” software
rather than packet −write software.
DThe m3u playlists are not compatible
with the audio player.
DMP3i (MP3 interactive) and MP3PRO
formats are not compatible with the au-
dio player.
DThe MP3 player is compatible with
VBR (Variable Bit Rate).
DWhen playing back files recorded as
VBR (Variable Bit Rate) files, the play
time will not be correctly displayed if
fast− forward or reverse operations are
used.
DIt is not possible to check folders that
do not include MP3/WMA files.
DMP3/WMA files in folders up to 8 levels
deep can be played. However, the
start of playback may be delayed when
using discs containing numerous lev-
els of folders. For this reason, we rec-
ommend creating discs with no more
than two levels of folders.
DIt is possible to play up to 192 folders or
255 files on one disc.
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AUDIO/VIDEO SYSTEM
270
TERMS
Packet write—
This is a general term that describes the
process of writing data on−demand to
CD− R, etc., in the same way that data is
written to floppy or hard discs.
ID3 Tag—
This is a method of embedding track −re-
lated information in an MP3 file. This em-
bedded information can include the track
title, the artist’s name, the album title, the
music genre, the year of production, com-
ments and other data. The contents can
be freely edited using software with ID3 tag
editing functions. Although the tags are re-
stricted to the number of characters, the in-
formation can be viewed when the track is
played back.
WMA Tag—
WMA files can contain a WMA tag that is
used in the same way as an ID3 tag. WMA
tags carry information such as track title,
artist name.
ISO 9660 format—
This is the international standard for the
formatting of CD −ROM folders and files.
For the ISO 9660 format, there are two lev-
els of regulations.
Level 1:
The file name is in 8.3 format (8 character
file names, with a 3 character file exten-
sion. File names must be composed of
one −byte capital letters and numbers. The
“_” symbol may also be included.)
Level 2:
The file name can have up to 31 characters
(including the separation mark “.” and file
extension). Each folder must contain few-
er than 8 hierarchies. m3u—
Playlists created using “WINAMP” soft-
ware have a playlist file extension (.m3u).
MP3—
MP3 is an audio compression standard de-
termined by a working group (MPEG) of
the ISO (International Standard Organiza-
tion). MP3 compresses audio data to
about 1/10 the size of that on conventional
discs.
WMA—
WMA (Windows Media Audio) is an audio
compression format developed by Micro-
soft. It compresses files into a size smaller
than that of MP3 files. The decoding for-
mats for WMA files are Ver. 7, 8, and 9.
GX470_Navi_U (OM60D58U) 07/06/16