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Export Audio Mixdown
• Mode
The WMA encoder can use either a constant bit rate or a
variable bit rate, or it can use lossless encoding for encod-
ing to stereo. The options on this menu are as follows:
• Bit Rate/Quality
This menu allows you to set the desired bit rate. The avail-
able bit rate settings vary depending on the selected mode
and/or output channels (see above). If the Variable Bitrate
mode is used, the menu allows you to select from various
levels of quality, with 10 being the lowest and 100 the high-
est. Generally, the higher the bitrate or quality you select,
the larger the final file will be.
Advanced tab
• Dynamic Range Control
These controls allow you to define the dynamic range of
the encoded file. The dynamic range is the difference in
dB between the average loudness and the peak audio
level (the loudest sounds) of the audio. These settings af-
fect how the audio is reproduced if the file is played on a
Windows XP computer with a player from the Windows
Media series, and the “Quiet Mode” feature of the player is
activated to control the dynamic range.
The dynamic range is automatically calculated during the
encoding process, but you can specify it manually as well.
To manually specify the dynamic range, first put a check-
mark in the box to the left by clicking in it, and then enter
the desired dB values in the Peak and Average fields. You
can enter any value between 0 and -90dB. Note, how-
ever, that it is usually not recommended to change the Av-
erage value, since this affects the overall volume level of
the audio and therefore can have a negative effect on the
audio quality.
The Quiet Mode in a Windows Media player can be set to
one of three settings. Below, these settings are listed to-
gether with an explanation of how the Dynamic Range set-
tings affect them:
• Off: If Quiet Mode is off, the dynamic range settings that were
automatically calculated during the encoding will be used.
• Little Difference: If this is selected and you have not manually
changed the dynamic range settings, the peak level will be
limited to 6dB above the average level during playback. If you
have manually specified the dynamic range, the peak level will
be limited to the mean value between the peak and average
values you specified.
• Medium Difference: If this is selected and you have not manu-
ally changed the dynamic range settings, the peak level will be
limited to 12dB above the average level. If you have changed
the dynamic range, the peak level will be limited to the peak
value you specified.
Media tab
In these fields you can enter a number of text strings with
information about the file – title, author, copyright informa-
tion and a description of its contents. This information will
then be embedded in the file header and can be displayed
by some Windows Media Audio playback applications.
Mode Description
Constant Bitrate This will encode to a file with a constant bit rate (set in
the Bit Rate/Channels menu, see below). Constant bit
rate is preferably used if you want to limit the size of the
final file. The size of a file encoded with a constant bit
rate is always the bit rate times the duration of the file.
Variable Bitrate Encodes to a file with a variable bit rate, according to a
quality scale (the desired quality is set in the Bit Rate/
Quality menu, see below). When you encode with vari-
able bit rates, the bit rate fluctuates depending on the
character and intricacy of the material being encoded.
The more complex passages in the source material, the
higher the bit rate – and the larger the final file.
Lossless Encodes to a file with lossless compression.