Game Development Reference
In-Depth Information
sounds just like the 44,100 frequency rate, as does the 22,050 frequency. The 16,000 or
11,025 frequency rates do not sound as “bright” but are still usable, so I used the
11,025 rate, to get an even 4X downsample of the data. This is because downsampling
by an
even
2X (100%) or 4X (200%) will always provide the best result. This is be-
cause of the math involved leaving no “partial” samples (or pixels, since the same
concept applies with imaging).
Next, let's use the
File Export
work process. If you want to see this on a menu,
this menu sequence can be seen in
Figure 15-1
, and is shown on the File menu, above
Export Selection option. In the Export File dialog, which can be seen in
Figure 15-7
,
you can save the new version of the file using a
different file name
, so that you have
both the original uncompressed data in the left.wav file and the new compressed (ste-
reo) data in the leftstereo.wav file. Name this file
leftstereo
, and click on the
Save
but-
ton, to save it as an uncompressed
16-bit PCM WAV
file, as shown on the left side of
Figure 15-7
.
Use the File
Export dialog, name the file leftstereo, Save the file, then use File
Open to check
its file size
The next thing that we will want to do is use the same work process shown back in
Figure 15-3
,
and use the
File Open
menu sequence, to open the
Select one or
more audio files
dialog, shown on the right side of
Figure 15-7
, which will allow us to
mouse-over the
leftstereo.wav
file and see that the size is
28.0 KB
, which is four times
less data than the original 112 KB source file size, just as we expected!
Therefore, we've reduced our memory requirements for this audio file that states
the word “left” from one-ninth of a megabyte (112 KB), to one-thirty-sixth of a mega-
byte (28KB). This means that you can have
36
audio assets of this size, and still be us-
ing only one single megabyte of system memory! When I created the other five audio
assets, this one turned out to be the largest, and the smallest (up and s, as you may have
guessed) were less than 4KB each!
