448 CHAPTER 12: Digital Audio: Providing Aural Feedback for UI Designs Using SoundPool
In this chapter, we’ll utilize Android’s SoundPool digital audio sequencing class to add amazing
sound effects to the ImageButton UI elements in your SlidingPaneLayout design. We will do this to
add aural feedback for your users. We’ll learn how to implement this SoundPool engine correctly
in your Android applications, as this is no easy task. Digital audio sequencing and synthesis is an
advanced topic indeed, but a key part of an Android app.
Audacity 2: Creating Digital Audio Assets
In this section of the book, you’ll learn how to use the open source audio engineering software called
Audacity, currently at version 2.0.5. First, we will make sure that Audacity has all of the plug-ins and
codecs installed that are available (for free) for the software and which will make your audio editing
environment far more powerful. Then we’ll learn how to use the software to create digital audio
assets in some of the Android OS audio formats.
Audacity Plug-Ins: Adding Codecs and Features
Assuming that you downloaded and installed Audacity 2.0.5 back in Chapter 1, we will now need to
add in some “plug-ins” which will greatly enhance the feature set of the software. We will also add in
many of the popular codecs which are now supported in the Android OS.
Visit the audacity.sourceforge.net web site and download Audacity 2.0.5 (if you haven’t already),
and install it. Click on the Other Audacity Downloads for Windows link, shown on the left in
Figure 12-1, to access the Optional Downloads area of the web site, shown on the right side of
Figure 12-1. The most important .EXE installers to focus on are the LADSPA plug-ins, the LAME
MP3 encoder, and the FFmpeg import and export library (MPEG-4).
Figure 12-1. Visit audacity.sourceforge.net and click on Other Audacity Downloads for Windows to display the Optional
Downloads links
Algorithms that add features and codecs to Audacity are kept in the Plug-Ins folder, so adding
features to this software package is as easy as exiting the software (if it is running), copying a file or
files into this folder, and restarting the software again. Figure 12-2 shows your Audacity\Plug-Ins
folder, with 22 plug-in files installed.