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KW-M741BT | Audio File Compatibility

Audio File Specification

About AAC, MP3, WMA, WAV, FLAC and Vorbis

The playable AAC/MP3/WMA/WAV/FLAC/Vorbis file (hereafter called Audio file) and the media format has the following limitation. The Audio file, which is not conforming to the specification, may not play normally, or the file and folder names may not display correctly.

Playable Audio file

MP3 Extension .mp3
Format MPEG 1/2 Audio Layer 3 file
Transfer bit rate 8-320 kbps / Variable Bit Rate
Sampling frequency 16 - 48 kHz
ID3 Tag (Ver.1) Ver1.0/ 1.1 (Title/ Artist/ Album)
ID3 Tag (Ver.2) Ver2.2/ 2.3/ 2.4 (Title/ Artist/ Album)
WMA Extension .wma
Format The file in accordance with Windows Media Audio
Transfer bit rate 8-320 kbps
Sampling frequency 16 - 48 kHz
DRM file
WMA Tag (Content Description) (Title/ Artist/ Album)
AAC-LC Extension .m4a
Format AAC LC (2ch) HE-AAC (V1,V2)
Transfer bit rate 8-320 kbps / Variable Bit Rate
Sampling frequency 16 - 48 kHz
DRM file
Channel Stereo/Monaural
iTunes m4a Meta-data (Song Info.) (Title/ Artist/ Album)
WAV Extension .wav
Format RIFF waveform Audio Format (only for LinearPCM)
Sampling frequency 16 - 192 kHz
Bit count 16/ 24 bit
Channel Stereo/Monaural
FLAC Extension .flac
Format Free Lossless Audio Codec (FLAC)
Sampling frequency 16 - 192 kHz
Bit count 16/ 24 bit
Channel Stereo/Monaural
Vorbis Extension .ogg
Format vorbis
Sampling frequency 16 - 48 kHz
Bit count 16 bit

Do not attach the extensions to files other than the Audio file. If the extension is attached, the file, which is not the Audio file, will play and outputs a loud noise, causing damage to the speaker.

The files with copy protection cannot be played.

Audio files cannot be played depending on the encoding software setting, USB device type, and/or recording conditions.

The unit may not be compatible with upgrade of compression format standard and additional specifications.

There are times when play time is not displayed correctly depending on the Audio file recording conditions.

Sound of WAVE file may be interrupted depending on the performance of the recording media.

Playable storage media file system

USB device File system (Windows) *1 FAT16
File system (Macintosh)
File system (UNIX)

*1 Multi Partition : Not compatible (Some USB devices may have multiple partitions that will be invisible on Windows OS.)

Limitation of structure for the file and the folder

USB device Maximum number of folder layers 8
Maximum number of folders (per device) 999
Maximum number of files (per device) 9999

It may take time to start playing depending on the recording conditions such as file hierarchy and folder structure.

This includes the Root folder (the folder in the top level). The number of folders shown on your PC is less than it by 1.

The maximum number of characters for display

File/Folder name 255 characters
MP3 ID3 Tag 255 characters

Number of characters is based on byte unit.

File/Folder name is the number of the characters including the extensions.

This unit can display the following versions of MP3 ID3 tag: version 1.0/ 1.1/ 2.2/ 2.3/ 2.4.

AAC ID3 Tag cannot be displayed.

Video File Specification

Acceptable video files

MPEG-1 Extension .mpg, .mpeg
Format MPEG-1
Picture size 352 × 240, 352 × 288
Audio format MPEG Audio Layer 2
MPEG-2 Extension .mpg, .mpeg
Format MPEG-2
Picture size 720 × 480, 720 × 576
Audio format MPEG Audio Layer 2
MPEG-4 Extension .mp4, .avi
Format MPEG-4
Picture size 1920 × 1080
Audio format AAC-LC, MP3
H.264 Extension .mp4, .m4v, .avi, .flv
Format H.264/ MPEG-4 AVC
Picture size 1920 × 1080
Audio format AAC-LC, MP3
WMV Extension .wmv
Format WMV 9 / VC-1
Picture size 1920 × 1080
Audio format WMA
MKV Extension .mkv
Video format H.264/ MPEG-4 AVC, MPEG-4
Audio format AAC-LC, MP3

About USB device

Notes on Use of the USB device

This unit can play audio files stored in the flash memory and digital audio player that have a USB port (these devices are referred to as USB devices in this document).
The following restrictions are placed on the types and usage of available USB devices:

Available USB Devices

USB standard USB 1.1/ USB 2.0
USB class Mass storage class (MSC device)
Current supply Max. 1.5 A (iPod/iPhone)

USB Mass Storage Class:
USB devices that the PC can recognize as an external storage without using any special driver or application software.

Contact the sales agent as to whether your USB device conforms to the USB mass storage class specs.

Using an unsupported USB device can result in abnormal playback or display of the audio/video file.
Even if you use the USB device conforming to the above specs, audio/video files cannot be played normally depending on the type or condition of the USB device.

Some of the functions is are limited with a certain USB device.

Normal operation and power supply is not guaranteed against every USB devices.

About the Connection of the USB device

Normal playback is not guaranteed when a cable other than the USB compatible cable is used. Connecting a cable whose total length is longer than 5 m can result in abnormal playback.

You cannot connect a USB device via a USB hub.

Install the USB device in the place where it will not prevent you from driving your vehicle properly.

Do not leave the USB device in the vehicle for a long time. It can deform or damage due to direct sunlight, high temperature, etc.

Take backups of the audio/video files used with this unit. The files can be erased depending on the operating conditions of the USB device.
We shall have no compensation for any damage arising out of erasure of the stored data.