239
3-2. Using the audio system
3
Inte
rior fe
atures
●
MP3 and WMA files
MP3 (MPEG Audio LAYER 3) is a standard audio compression format.
Files can be compressed to approximately 1/10 of their original size using
MP3 compression.
WMA (Windows Media Audio) is a Microsoft audio compression format.
This format compresses audio data to a size smaller than that of the MP3
format.
There is a limit to the MP3 and WMA file standards that can be used and to
the media/formats on which the files are recorded.
●
MP3 file compatibility
• Compatible standards
MP3 (MPEG1 AUDIO LAYERII, III, MPEG2 AUDIO LAYERII, III,
MPEG2.5)
• Compatible sampling frequencies
MPEG1 AUDIO LAYERII, III: 32, 44.1, 48 (kHz)
MPEG2 AUDIO LAYERII, III: 16, 22.05, 24 (kHz)
MPEG2.5: 8, 11.025, 12 (kHz)
• Compatible bit rates (compatible with VBR)
MPEG1 AUDIO LAYERII, III: 32-320 (kbps)
MPEG2 AUDIO LAYERII, III: 32-160 (kbps)
MPEG2.5: 32-160 (kbps)
• Compatible channel modes: stereo, joint stereo, dual channel and
monaural
●
WMA file compatibility
• Compatible standards
WMA Ver. 7,8,9
• Compatible sampling frequencies
HIGH PROFILE 32, 44.1, 48 (kHz)
• Compatible bit rates
HIGH PROFILE 32-320 (kbps, VBR)
●
File names
The only files that can be recognized as MP3/WMA and played are those
with the extension .mp3 or .wma.