JVC TH-A25 manual MP3/JPEG Introduction

MP3/JPEG Introduction

This system is incorporated with an MP3 decoder and JPEG decoder. You can play back MP3 tracks (files) and JPEG files recorded on CD-Rs and CD-RWs.

•Notice that “files” and “tracks” are used interchangeably in the MP3 explanation.

Notes:

This system can play back a disc containing both MP3 and JPEG

files.

What is MP3?

MP3 is an abbreviation of Motion Picture Experts Group (or MPEG) Audio Layer 3. MP3 is simply a file format with a data compression ratio of 1:10 (128 Kbps*). That means, by using MP3 format, one CD-R or CD-RW can contain 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 measuring unit used is Kbps (1000 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 File Compatibility

•This system can only read MP3 files that are recorded in the format that is compliant with ISO 9660 Level 1 and Level 2, and Joliet.

•The system can read or play MP3 files only with the extension code—“.mp3”.

Disc structure—How are MP3 files recorded and played back?

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

During recording, the files and directories can be arranged in a way similar to arranging files and folder/directories of computer data. “Root” is similar to the root of a tree. Every file and directory can be linked to the root.

In compliance with ISO 9660, the maximum allowable depth of nested directories—so-called “hierarchy”—is 300 (inclusive of the root).

Playback order, files search order, and directory search order of the MP3 files 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 folders/ directories and the files.

Note on MP3 discs

MP3 discs (either CD-R or CD-RW) require a longer readout time. (It differs due to the complexity of the directory/file configuration.)

What is JPEG?

A still-picture data compression system proposed by the Joint Photographic Expert Group, which features small decrease in image quality in spite of its high compression ratio.

Disc structure

On a JPEG disc, each still picture (material) is recorded as a file. Files are usually grouped into a folder. Folders can also include another folders, creating hierarchical folder layers.

•A maximum of 5 000 images can be stored on one CD.

•If there is any type of files other than JPEG files in a folder, those files are also counted in the total number of 5 000.

NOTES on JPEG discs

•JPEG discs (either CD-R or CD-RW) require a longer readout time. (It differs due to the complexity of the directory/file configuration.)

•When making a JPEG disc, select ISO 9660 Level 1, Level 2 or Joliet as the disc format.

•This system supports “multi-session” discs (up to 99 sessions).

•This system cannot play “packet write” discs.

•The system can read or play JPEG files only with the extension code—“.jpg”.

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

For in-depth information about a disc to be played back, see “Disc Introduction—DVD/VCD/SVCD/CD” on page 21.

Playback Information on the display

MP3	L R
	SW

File name

L R

SW

File No. Elapsed playing time

JPEG	L R
	SW

File No. Fixed to “0: 00: 00”

L R

SW

File name

30