[JAVA][Beginning Java 8 Games Development]

Chapter 5 ■ An Introduction to Game Design: Concepts, Multimedia, and Using Scene Builder
Digital Audio Streaming: Captive Audio vs. Streaming Audio
As with digital video data, digital audio data can be either captive within the application distribution file (in the case
of Java, a .JAR file) or streamed, using remote data servers. Similar to digital video, the upside to streaming digital
audio data is that it can reduce the data footprint of the application file. The downside is reliability. Many of the same
concepts apply equally well to audio and video. Streaming audio will save the data footprint, because you do not have
to include all that heavy new media digital audio data in your .JAR files. So, if you are planning on coding a Jukebox
application, you may want to consider streaming your digital audio data; otherwise, try to optimize your digital audio
data so that you can include them (captive) inside the .JAR file. This way, the data will always be available to the
application’s users when they need it!
The downside to streaming digital audio is that if a user’s connection (or the audio data server) goes down, your
digital audio file may not always be present for your end users to play and listen to, using your game application! The
reliability and availability of digital audio data are a key factor to be considered on the other side of this streamingversus-captive
trade-off. The same would apply to digital video assets as well.
Again, as with digital video, one of the primary concepts in regard to streaming your digital audio is the bit rate of
the digital audio data. As you learned in the previous section, the bit rate is defined during the compression process.
Digital audio files that need to support lower bit-rate bandwidth are going to have more compression applied to the
audio data, which will result in lower quality. These will stream (play back) more smoothly across a greater number of
devices, because fewer bits can be quickly transferred as well as processed more easily.
Digital Audio in JavaFX: Supported Digital Audio Codecs and Data Formats
There are considerably more digital audio codecs in JavaFX than digital video codecs, as there is only one video
codec, MPEG-4 H.264 AVC. Android audio support includes .MP3 (MPEG-3) files, Windows WAVE (Pulse Code
Modulation [PCM] audio) .WAV files, .MP4 (or .M4A) MPEG-4 AAC (Advanced Audio Coding) audio, and Apple’s
AIFF (PCM) file format. The most common format supported by JavaFX (and thus Java 8) is the popular .MP3 digital
audio file format. Most of you are familiar with MP3 digital audio files, owing to music download web sites, such as
Napster or Soundcloud, and most of us collect songs in this format to use on MP3 players and in CD-ROM- or DVD-
ROM-based music collections. The MP3 digital audio file format is popular because it has a fairly good compressionto-quality
ratio and is widely supported.
MP3 is an acceptable format to use in a Java 8 application, so long as you get the highest quality level possible
out of it, using an optimal encoding work process. It is important to note that, like JPEG (used for images), MP3 is a
lossy audio file format, in which some of the audio data (and thus quality) are thrown away during your compression
process and cannot be recovered.
JavaFX does have two lossless audio compression codecs, AIFF and WAVE. Many of you are familiar with these,
as they were the original audio formats used with the Apple Macintosh and Microsoft Windows OSs, respectively.
These files use PCM audio, which is lossless (in this case, because there is no compression applied whatsoever!).
“PCM,” which, as stated, stands for “pulse code modulation,” refers to the data format it holds.
PCM audio is commonly used for CD-ROM content as well as telephony applications. This is because PCM WAVE
audio is an uncompressed digital audio format, with no CPU-intensive compression algorithms applied to the data
stream. Thus, decoding (CPU data processing) is not an issue for telephony equipment or for CD players.
For this reason, when you start compressing digital audio assets into the various file formats, you can use PCM
as your baseline file format. It allows you to look at the difference between PCM (WAVE) and MP3 and MP4 audio
compression results to get an idea of how much data footprint optimization you are getting for your JAR file; more
important, you can also see how your sample resolution and sample frequency optimization are going to affect the
system memory used for your game’s audio effects. Even if you used an MP3 or MP4 format, it would still have to be
decompressed into memory before the audio asset could be used with the AudioClip class and employed as a sound
effect in a Java 8 game.
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