Learning the Inner Workings of Audio Part 1: RESEARCH

For the past 48 hours, my life have been succumbed to study. I have been tasked with making a multi-platform Audio Engine for games, or simply a Audio Library whose focus will be for playing, loading, and editing sounds/music for games. To do this I will be using existing first party libraries to do the heavy lifting while the library I create will be able to reference those existing libraries when needed.

But enough about that, onto what I learned.

Generally, gaming audio files run on their own threads at run-time and usually sounds needed for a level are pre-loaded into memory prior to actually playing the file and unloaded when it is no longer needed. Have you ever noticed your game freezes but the background audio is still playing fine, this is the reason why.  One of the most commonly used file formats used in games is the .wav file due to its heavily documented and easy to read/write file format. This knowledge is needed since some api's such as XAudio2 doesn't actually handle loading the data itself but rather once the data is loaded, it accesses the necessary hardware to play that sound. This is not universally accepted as CoCos2d, another api designed specifically with games in mind, handles all the loading and playing of files itself.

Another common thing I found among different api's was the use of  Instancing and Asynchronous Callbacks. For sounds that may stay for the length of the game such as background music, an instance of sound kind of audio device is create which manages the audio specifically for the background music. A separate instance of an audio or several instances of an object might be used just to handle specific sound effects.  This way the BGM and sound effects can vary in volume and other things as the player wishes.  Callbacks are used mostly with streaming the audio so that huge music files aren't loaded into memory all at once and they are asynchronous as to not block the rest of the gameplay while its waiting for some feedback to play a sound

Well that's all for today, next time I'll be delving more into XAudio2 and how one loads and plays a sound with it. Until then, you can read up more on XAudio2 on MSDN.

In the meantime, You've activated my trap card! Goodbye!