User Manual

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935
Figure 84-10: The MP3 export options.
If you don’t have any specific needs or
requirements for your MP3 file, the default settings
in the MP3 export options window will give you
very good results. If you have specific needs, the
export options give you the following choices:
Channels: The choices here are Mono, Stereo or
Auto. This option lets you force the MP3 to be
either Mono or Stereo. If you want the MP3 to
automatically match the channel format (mono or
stereo) of the source material, use the Auto setting.
Mono files are about half the size of stereo files.
Mono is appropriate if you don’t have stereo
speakers or if your audio files are monaural. If
you’ll be listening to your MP3 files using your
stereo system, choose Stereo or Auto.
Stereo mode: The two choices here are Normal and
Joint Stereo. In Normal mode, your MP3 files
contain one track for the right stereo channel and
one track for the left. In many cases, the two
channels contain related information. In Joint
Stereo mode, one channel carries the information
that is identical on both channels, and the other
channel carries the unique information. At bit rates
of 128 kbps and below, this can improve the sound
quality of your converted audio. Generally, Joint
Stereo mode is the best choice.
Output Sample Rate: The choices here are Auto,
and a list of specific bit rates. The best choice is
usually the Auto setting, which makes the MP3
match the source material sample rate automati-
cally. The sample rate is the number of times per
second that the music waveforms are captured
digitally. The higher the sample rate, the higher the
quality and the larger the file size. Be sure to choose
a sample rate that is no higher than the rate used to
originally store the music, or you’ll waste disk
space and streaming bandwidth. CD quality, for
example, is 44.1 kHz, so choosing a higher rate
when you’re encoding from a CD is unnecessary.
Encoding mode: This option lets you specify the
bit rate (number of bits per second). This is an
important setting because it has a high degree of
impact on both the file size and quality of the
sound. The four choices are summarized below:
VBR (variable bit rate) quality: This option
appears if you’ve chosen one of the two VBR
encoding modes above. If so, this option lets you
control the quality of VBR encoding on a scale
from 10 (good) to 100 (best).
Bit Rate: This option appears if you’ve chosen
either the average or constant bit rate encoding
modes above. If so, this option lets you specify the
desired bit rate in kilo bits per second (kbps). The
Encoding mode What it does Explanation
Variable Bit Rate
(VBR) Standard
Varies the bit rate
as needed, depend-
ing on the material.
In general, you’ll get
the best results with
this option (the best
sound and the small-
est file).
Variable Bit Rate
(VBR) Fast
Same as above,
except that the
encoding process
will be faster.
The results will still be
good, but perhaps not
quite as good as the
standard VBR above.
Average Bit Rate The bit rate is still
variable, but the
encoder restricts
the overall average
bit rate of the entire
file to the specific
value you specify in
the Bit Rate menu.
Use this encoding
method if you need to
restrict the file size or
overall bandwidth.
Constant Bit Rate Forces the same bit
rate throughout the
file, regardless of
the material.
This gives you the
most control over the
file size and streaming
bandwidth.