JVC UX-J66V Disc Introduction, What is MP3?, MP3 disc structure, MP3 group/track configuration

Disc Introduction

English

This unit has been designed to playback the following CDs:

•CD (Audio CD)

•CD-R (CD-Recordable)

•CD-RW (CD-Rewritable)

•MP3 disc (MP3 files recorded on a CD-R or CD-RW)

What is MP3?

MP3 is an abbreviation of Motion Picture Experts Group 1 (or MPEG-1) Audio Layer 3. MP3 is simply a file format with a data compression ratio of 1:10 (128 kbps*). By using MP3 format, one CD-R or CD-RW can contains 10 times as much data volume as a regular CD can.

*Bit rate is the average number of bits that one second of audio data will consume. The unit uses kbps (1,000 bits per second). To get a better audio quality, choose a higher bit rate. The most popular bit rate for encoding (recording) is 128 kbps.

MP3 disc structure

On an MP3 disc, each song (material) is recorded as a file. Files are grouped into a directory (or folder). Directories can also include other directories, creating hierarchical directory layers. (See “How are MP3 files recorded and played back?” ).

This unit manages files and directories as “tracks” and “groups.” This unit can recognize up to 255 tracks, up to 64 groups per disc. The unit ignores those exceeding the maximum numbers and cannot play them back.

About MP3 discs

•MP3 discs (either CD-R or CD-RW) require a longer readout time. (It varies due to the complexity of the recording configuration.)

•When making an MP3 disc, select ISO 9660 Level 1 or Level 2 as the disc format.

•This unit does not support multisession recording.

•This unit can play MP3 files only with the following file extensions— “.MP3”, “.Mp3”, “.mP3”, and “.mp3.”

•Files other than MP3 are ignored.

•Some MP3 discs may not be played back because of their disc characteristics or recording conditions.

How are MP3 files recorded and played back?

MP3 “tracks (files)” can be recorded in “group”—folders or directories, in PC terminology.

During recording, the tracks and groups can be arranged similarly to the tracks and folders/directories of computer data. “Root” is similar to the root of a tree. Every track and group can be linked to the root.

In compliance with ISO 9660, the maximum allowable depth of nested directories—so called “hierarchy”—is eight (inclusive of the root).

Playback order, track search order, and group search order of the MP3 tracks recorded on a disc are determined by the writing (or encoding) application; therefore, playback order may be different from the one you have intended while recording the groups and the tracks.

The illustration shows an ordinary example of how MP3 tracks are recorded on a CD-R or CD-RW, how they are played back and how they are searched for on this unit.

•The numbers in circles next to the MP3 tracks ( ) indicate the playback order and search order of the MP3 tracks. Normally this unit plays back MP3 tracks in the recorded order.

•The numbers inside the groups indicate the playback order and search order of the groups on an MP3 disc. Normally this unit plays back MP3 tracks in the groups in the recorded order.

The groups marked with asterisk (*) will be skipped since they do not include any MP3 tracks.

MP3 group/track configuration:

Hierarchy

Root

1

* 2

3
4	7

*

8

* 5

6

1 Groups

MP3 tracks

14